78 results on '"Stephan Kannengiesser"'
Search Results
2. Volumetric Evaluation of 3D Multi-Gradient-Echo MRI Data to Assess Whole Liver Iron Distribution by Segmental R2* Analysis: First Experience
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Arthur P, Wunderlich, Holger, Cario, Stephan, Kannengießer, Veronika, Grunau, Lena, Hering, Michael, Götz, Meinrad, Beer, and Stefan Andreas, Schmidt
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Radiology, Nuclear Medicine and imaging - Abstract
Purpose MR transverse relaxation rate R2* has been shown to be useful for monitoring liver iron overload. A sequence enabling acquisition of the whole liver in a single breath hold is now available, thus allowing volumetric hepatic R2* distribution studies. We evaluated the feasibility of computer-assisted whole liver segmentation of 3 D multi-gradient-echo MRI data, and compared whole liver R2* determination to analyzing only a single slice. Also, segmental R2* differences were studied. Materials and Methods The liver of 44 patients, investigated by multi-gradient echo MRI at 1.5 T, was segmented and divided into nine segments. Segmental R2* values were examined for all patients together and with respect to two criteria: average R2* values, and reason for iron overload. Correlation of single-slice and volumetric data was tested with Spearman’s rank test, segmental and group differences were evaluated by analysis of variance. Results Whole-liver R2* values correlated excellent to single slice data (p Conclusion Our results suggest inhomogeneous hepatic iron distribution. Low R2* in S1 may be explained by its special vascularization. Key Points Citation Format
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- 2022
3. Preliminary Study of <scp>Confounder‐Corrected</scp> Fat Fraction and <scp>R2</scp> * Mapping of Bone Marrow in Children With Acute Leukemia
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Linlin Wang, Dao Wang, Jiao Chen, Mengtian Sun, Dominik Nickel, Stephan Kannengiesser, Feifei Qu, Jingxia Zhu, Cuiping Ren, Yong Zhang, and Jingliang Cheng
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Radiology, Nuclear Medicine and imaging - Published
- 2023
4. A Faster Prostate <scp>MRI</scp> : Comparing a Novel Denoised, <scp> Single‐Average T 2 </scp> Sequence to the Conventional <scp> Multiaverage T 2 </scp> Sequence Regarding Lesion Detection and <scp>PI‐RADS</scp> Score Assessment
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Colm B. Kelleher, Jacob Macdonald, Tracy A. Jaffe, Brian C. Allen, Kevin R. Kalisz, Travis H. Kauffman, Jordan D. Smith, Kimberly R. Maurer, Sarah P. Thomas, Aaron D. Coleman, Islam H. Zaki, Stephan Kannengiesser, Kyle Lafata, Rajan T. Gupta, and Mustafa R. Bashir
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Radiology, Nuclear Medicine and imaging - Published
- 2023
5. Magnetic Resonance Elastography for Assessing Fibrosis in Patients with Crohn’s Disease: A Pilot Study
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Myriam Choukour, Gabriela Hossu, Jacques Felblinger, Bénédicte Caron, Stephan Kannengiesser, Freddy Odille, Silvio Danese, Khalid Ambarki, Valérie Laurent, Laurent Peyrin-Biroulet, and François Avila
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Adult ,medicine.medical_specialty ,Physiology ,Pilot Projects ,Gastroenterology ,Crohn Disease ,Fibrosis ,Internal medicine ,Intestinal Stricture ,medicine ,Humans ,Prospective Studies ,Prospective cohort study ,Crohn's disease ,medicine.diagnostic_test ,business.industry ,Area under the curve ,Magnetic resonance imaging ,Hepatology ,equipment and supplies ,medicine.disease ,Magnetic Resonance Imaging ,Magnetic resonance elastography ,Elasticity Imaging Techniques ,business - Abstract
Patients with Crohn’s disease can develop intestinal strictures, containing various degrees of inflammation and fibrosis. Differentiation of the main component of a stricturing lesion is the key for defining the therapeutic management. We assessed for the first time the accuracy of magnetic resonance elastography in detecting intestinal fibrosis and predicting clinical course in patients with Crohn’s disease. This was a prospective study of adult patients with Crohn’s disease and magnetic resonance imaging examination, including magnetic resonance elastography, between April 2019 and February 2020. The association between the bowel stiffness value and the degree of fibrosis was evaluated. The relationship between the stiffness value and the occurrence of clinical events was also investigated. A total of 69 patients were included. The stiffness value measured by magnetic resonance elastography was correlated with the degree of fibrosis (p
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- 2021
6. A Faster Prostate MRI: Comparing a Novel Denoised, Single-Average T
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Colm B, Kelleher, Jacob, Macdonald, Tracy A, Jaffe, Brian C, Allen, Kevin R, Kalisz, Travis H, Kauffman, Jordan D, Smith, Kimberly R, Maurer, Sarah P, Thomas, Aaron D, Coleman, Islam H, Zaki, Stephan, Kannengiesser, Kyle, Lafata, Rajan T, Gupta, and Mustafa R, Bashir
- Abstract
The TTo determine whether a denoised, single-average TRetrospective.A total of 45 males (age range 60-75 years) who underwent clinically indicated prostate MRI examinations, 21 of whom had pathologically proven prostate cancer.A 3 T; TNine readers randomly assessed complete exams including TGeneralized linear mixed effects models for differences in lesion detection, image quality features, and overall preference between TThere was no significant difference between sequences regarding identification of lesions with PI-RADS ≥3 (P = 0.10) or PI-RADS score (P = 0.77). Reader agreement was excellent for lesion identification (ICC = 0.84). There was no significant overall preference between the two sequences regarding image quality (P = 0.07, 95% CI: [-0.23, 0.01]). Reader agreement was good regarding sequence preference (ICC = 0.62).Use of single-average, denoised T3.Stage 3.
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- 2022
7. Hepatic Iron Quantification Using a <scp>Free‐Breathing 3D</scp> Radial Gradient Echo Technique and Validation With a <scp>2D</scp> Biopsy‐Calibrated <scp> R 2 </scp> * Relaxometry Method
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Utsav Shrestha, Xiaodong Zhong, Chris Goode, Ralf B. Loeffler, Joseph L. Holtrop, Cara E. Morin, Shawyon Chase Rohani, Jane S. Hankins, Aaryani Tipirneni-Sajja, Ayaz Khan, Stephan Kannengiesser, and Claudia M. Hillenbrand
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Male ,Relaxometry ,Contouring ,Reproducibility ,Iron Overload ,Adolescent ,Wilcoxon signed-rank test ,business.industry ,Intraclass correlation ,Biopsy ,Iron ,Reproducibility of Results ,Magnetic Resonance Imaging ,Liver ,Statistical significance ,Linear regression ,Humans ,Female ,Radiology, Nuclear Medicine and imaging ,Analysis of variance ,Child ,Nuclear medicine ,business ,Retrospective Studies ,Mathematics - Abstract
Background Hepatic iron content (HIC) is an important parameter for the management of iron overload. Non-invasive HIC assessment is often performed using biopsy-calibrated two-dimensional breath-hold Cartesian gradient echo (2D BH GRE) R2 * -MRI. However, breath-holding is not possible in most pediatric patients or those with respiratory problems, and three-dimensional free-breathing radial GRE (3D FB rGRE) has emerged as a viable alternative. Purpose To evaluate the performance of a 3D FB rGRE and validate its R2 * and fat fraction (FF) quantification with 3D breath-hold Cartesian GRE (3D BH cGRE) and biopsy-calibrated 2D BH GRE across a wide range of HICs. Study type Retrospective. Subjects Twenty-nine patients with hepatic iron overload (22 females, median age: 15 [5-25] years). Field strength/sequence Three-dimensional radial and 2D and 3D Cartesian multi-echo GRE at 1.5 T. Assessment R2 * and FF maps were computed for 3D GREs using a multi-spectral fat model and 2D GRE R2 * maps were calculated using a mono-exponential model. Mean R2 * and FF values were calculated via whole-liver contouring and T2 * -thresholding by three operators. Statistical tests Inter- and intra-observer reproducibility was assessed using Bland-Altman and intraclass correlation coefficient (ICC). Linear regression and Bland-Altman analysis were performed to compare R2 * and FF values among the three acquisitions. One-way repeated-measures ANOVA and Wilcoxon signed-rank tests, respectively, were used to test for significant differences between R2 * and FF values obtained with different acquisitions. Statistical significance was assumed at P Results The mean biases and ICC for inter- and intra-observer reproducibility were close to 0% and >0.99, respectively for both R2 * and FF. The 3D FB rGRE R2 * and FF values were not significantly different (P > 0.44) and highly correlated (R2 ≥ 0.98) with breath-hold Cartesian GREs, with mean biases ≤ ±2.5% and slopes 0.90-1.12. In non-breath-holding patients, Cartesian GREs showed motion artifacts, whereas 3D FB rGRE exhibited only minimal streaking artifacts. Data conclusion Free-breathing 3D radial GRE is a viable alternative in non-breath-hold patients for accurate HIC estimation. Level of evidence 3 TECHNICAL EFFICACY: Stage 2.
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- 2021
8. Comparison of spin-echo echo-planar imaging magnetic resonance elastography with gradient-recalled echo magnetic resonance elastography and their correlation with transient elastography
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Jin Woo, Yoon, Eun Sun, Lee, Hyun Jeong, Park, Sung Bin, Park, Young Youn, Cho, Stephan, Kannengiesser, and Joonho, Hur
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Liver Cirrhosis ,Liver ,Echo-Planar Imaging ,Elasticity Imaging Techniques ,Humans ,Reproducibility of Results ,Original Article ,Magnetic Resonance Imaging ,Retrospective Studies - Abstract
PURPOSE: This study aimed to assess the agreement between liver stiffness (LS) values obtained by the gradient-recalled echo (GRE) magnetic resonance elastography (MRE) and spin-echo echo-planar imaging (SE-EPI) MRE with those of transient elastography (TE), respectively. METHODS: We retrospectively included 48 participants who underwent liver MRE with both GRE and SE-EPI sequences in the same session and also TE within 1 year. We obtained LS values for MRE by drawing free-hand region of interest, and TE was performed using a FibroScan device. We assessed the relationship between the mean LS values obtained by each MRE sequence and TE using the correlation coefficients and Bland–Altman plots, respectively. We also compared LS values and technical failure rates of measured values from MRE between SE-EPI and GRE sequences using the paired t-test and McNemar’s test. The MRE failure was defined as the absence of pixel value with a confidence index above 95%. RESULTS: The LS values from SE-EPI and GRE sequences strongly correlated with those from TE (GRE; r = 0.73, P < .001 vs. SE-EPI; r = 0.79, P < .001). In addition, the LS values from the 2 MRE sequences showed excellent relationship (intraclass correlation coefficient, 0.94 [0.89-0.97], P < .001). The LS values from SE-EPI and GRE MRE were not significantly different (4.14 kPa vs. 3.88 kPa, P = .19). Furthermore, the technical success rate of SE-EPI MRE was superior to that of GRE (100% vs. 83.8%, P = .031). CONCLUSION: The measured LS values obtained using TE correlated strongly with those obtained using GRE and SE-EPI MRE techniques, even though SE-EPI-MRE resulted a higher technical success rate than GRE-MRE. Therefore, we believe that TE, GRE, and SE-EPI MR elastography techniques may complement each other according to the appropriate individual situation.
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- 2022
9. Comparison of Inline R2* MRI versus FerriScan for liver iron quantification in patients on chelation therapy for iron overload: preliminary results
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Kevin H.M. Kuo, Richard Ward, Gerard M Healy, Kartik S. Jhaveri, Osvaldo Espin-Garcia, and Stephan Kannengiesser
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Liver Iron Concentration ,Iron metabolism disorder ,Relaxometry ,medicine.medical_specialty ,medicine.diagnostic_test ,Receiver operating characteristic ,business.industry ,Interclass correlation ,Magnetic resonance imaging ,General Medicine ,Linear regression ,Calibration ,Medicine ,Radiology, Nuclear Medicine and imaging ,Radiology ,business ,Nuclear medicine - Abstract
MRI quantification of liver iron concentration (LIC) using R2 or R2* relaxometry requires offline post-processing causing reporting delays, administrative overhead, and added costs. A prototype 3D multi-gradient-echo pulse sequence, with inline post-processing, allows immediate calculation of LIC from an R2* map (inline R2*-LIC) without offline processing. We compared inline R2*-LIC to FerriScan and offline R2* calibration methods. Forty patients (25 women, 15 men; age 18–82 years), prospectively underwent FerriScan and the prototype sequence, which produces two R2* maps, with and without fat modeling, as well as an inline R2*-LIC map derived from the R2* map with fat modeling, with informed consent. For each map, the following contours were drawn: ROIs, whole-axial-liver contour, and an exact copy of contour utilized by FerriScan. LIC values from the FerriScan report and those calculated using an alternative R2 calibration were the reference standards. Results were compared using Pearson and interclass correlation coefficients (PCC, ICC), linear regression, Bland-Altman analysis, and estimation of area under the receiver operator curve (ROC-AUC). Inline R2*-LIC demonstrated good agreement with the reference standards. Compared to FerriScan, inline R2*-LIC with whole-axial-liver contour, ROIs, and FerriScan contour demonstrated PCC of 94.8%, 94.8%, and 92%; ICC 93%, 92.7%, and 90.2%; regression slopes 1.004, 0.974, and 1.031; mean bias 5.54%, 10.91%, and 0.36%; and ROC-AUC estimates 0.903, 0.906, and 0.890 respectively. Agreement was maintained when adjusted for sex, age, diagnosis, liver fat content, and fat-water swap. Inline R2*-LIC provides robust and comparable quantification of LIC compared to FerriScan, without the need for offline post-processing. • In patients being treated for iron overload with chelation therapy, liver iron concentration (LIC) is regularly assessed in order to monitor and adjust therapy. • Magnetic resonance imaging (MRI) is commonly used to quantify LIC. Several R 2 and R 2 * methods are available, all of which require offline post-processing. • A novel R 2 * MRI method allows for immediate calculation of LIC and provides comparable quantification of LIC to the FerriScan and recently published alternative R 2 * methods.
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- 2021
10. Application of deep learning-based super-resolution to T1-weighted postcontrast gradient echo imaging of the chest
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Simon Maennlin, Daniel Wessling, Judith Herrmann, Haidara Almansour, Dominik Nickel, Stephan Kannengiesser, Saif Afat, and Sebastian Gassenmaier
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Radiology, Nuclear Medicine and imaging ,General Medicine - Abstract
Objectives A deep learning-based super-resolution for postcontrast volume-interpolated breath-hold examination (VIBE) of the chest was investigated in this study. Aim was to improve image quality, noise, artifacts and diagnostic confidence without change of acquisition parameters. Materials and methods Fifty patients who received VIBE postcontrast imaging of the chest at 1.5 T were included in this retrospective study. After acquisition of the standard VIBE (VIBES), a novel deep learning-based algorithm and a denoising algorithm were applied, resulting in enhanced images (VIBEDL). Two radiologists qualitatively evaluated both datasets independently, rating sharpness of soft tissue, vessels, bronchial structures, lymph nodes, artifacts, cardiac motion artifacts, noise levels and overall diagnostic confidence, using a Likert scale ranging from 1 to 4. In the presence of lung lesions, the largest lesion was rated regarding sharpness and diagnostic confidence using the same Likert scale as mentioned above. Additionally, the largest diameter of the lesion was measured. Results The sharpness of soft tissue, vessels, bronchial structures and lymph nodes as well as the diagnostic confidence, the extent of artifacts, the extent of cardiac motion artifacts and noise levels were rated superior in VIBEDL (all P There was no significant difference in the diameter or the localization of the largest lung lesion in VIBEDL compared to VIBES. Lesion sharpness as well as detectability was rated significantly better by both readers with VIBEDL (both P Conclusion The application of a novel deep learning-based super-resolution approach in T1-weighted VIBE postcontrast imaging resulted in an improvement in image quality, noise levels and diagnostic confidence as well as in a shortened acquisition time.
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- 2022
11. Application of a Novel Iterative Denoising and Image Enhancement Technique in T1-Weighted Precontrast and Postcontrast Gradient Echo Imaging of the Abdomen
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Ahmed E. Othman, Sebastian Gassenmaier, Saif Afat, Rüdiger Hoffmann, Dominik Nickel, Stephan Kannengiesser, and Judith Herrmann
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Image quality ,Noise reduction ,Contrast Media ,030218 nuclear medicine & medical imaging ,03 medical and health sciences ,0302 clinical medicine ,Precontrast ,Interquartile range ,Abdomen ,medicine ,T1 weighted ,Humans ,Radiology, Nuclear Medicine and imaging ,Retrospective Studies ,medicine.diagnostic_test ,business.industry ,Magnetic resonance imaging ,General Medicine ,Image enhancement ,Image Enhancement ,Magnetic Resonance Imaging ,medicine.anatomical_structure ,Artifacts ,Nuclear medicine ,business ,030217 neurology & neurosurgery - Abstract
OBJECTIVES The aim of this study was to investigate the impact of a novel iterative denoising and image enhancement technique in T1-weighted precontrast and postcontrast volume-interpolated breath-hold examination (VIBE) of the abdomen on image quality, noise levels, and diagnostic confidence without change of acquisition parameters. MATERIALS AND METHODS Fifty patients were included in this retrospective, monocentric, institutional review board-approved study after clinically indicated magnetic resonance imaging of the abdomen including T1-weighted precontrast and postcontrast imaging. After acquisition of the standard VIBE (VIBES), images were processed with a novel reconstruction algorithm using the same raw data as for VIBES, resulting in a denoised and enhanced dataset (VIBEDE). Two different radiologists evaluated both datasets in a randomized order regarding sharpness of organs as well as vessels, noise levels, artifacts, overall image quality, and diagnostic confidence using a Likert scale ranging from 1 to 4 with 4 being the best. Furthermore, in the presence of focal liver lesions, the largest lesion was measured in the postcontrast dataset, and lesion detectability was analyzed using a Likert scale (1-4). RESULTS Precontrast and postcontrast sharpness of organs and sharpness of vessels were rated significantly superior by both readers in VIBEDE with a median of 4 (interquartile range, 0) compared with VIBES with a median of 3 (1) (all P's < 0.0001). Precontrast and postcontrast noise levels were also rated superior by both readers in VIBEDE with a median of 4 (0) compared with VIBES with a median of 3 (1) for precontrast and a median of 3 (0) (median of 3 [1] for reader 2) for postcontrast imaging (all P's < 0.0001).Overall image quality was also rated higher with a median of 4 (0) in VIBEDE versus 3 (1) in VIBES (P < 0.0001). Twenty-seven imaging studies contained liver lesions. There was no difference regarding the number and localization between the readers and between VIBES and VIBEDE. Lesion detectability was rated by both readers significantly better in VIBEDE with a median of 4 (0) compared with a median of 4 (1) for reader 1 and a median of 3 (1) for reader 2 (P = 0.001 for reader 1; P < 0.001 for reader 2). Consequently, diagnostic confidence was also significantly superior in VIBEDE versus VIBES with a median of 4 (0) for both (P = 0.001). Interreader agreement resulted in a Cohen κ of 0.76 for precontrast analysis as well as of 0.76 for postcontrast analysis. CONCLUSIONS Application of a novel iterative denoising and image enhancement technique in T1-weighted VIBE precontrast and postcontrast imaging of the abdomen is feasible, providing superior image quality, noise levels, and diagnostic confidence.
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- 2020
12. Combined Deep Learning-based Super-Resolution and Partial Fourier Reconstruction for Gradient Echo Sequences in Abdominal MRI at 3 Tesla: Shortening Breath-Hold Time and Improving Image Sharpness and Lesion Conspicuity
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Haidara Almansour, Judith Herrmann, Sebastian Gassenmaier, Andreas Lingg, Marcel Dominik Nickel, Stephan Kannengiesser, Simon Arberet, Ahmed E. Othman, and Saif Afat
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Radiology, Nuclear Medicine and imaging - Abstract
To investigate the impact of a prototypical deep learning-based super-resolution reconstruction algorithm tailored to partial Fourier acquisitions on acquisition time and image quality for abdominal T1-weighted volume-interpolated breath-hold examination (VIBEPatients with diverse abdominal pathologies, who underwent a clinically indicated contrast-enhanced abdominal VIBE magnetic resonance imaging at 3T between March and June 2021 were retrospectively included. Following the acquisition of the standard VIBEA total of 32 patients aged 59 ± 16 years (23 men (72%), 9 women (28%)) were included. For VIBEThe deep learning-based super-resolution reconstruction with partial Fourier in the slice phase-encoding direction enabled a reduction of breath-hold time and improved image sharpness and lesion conspicuity in T1-weighted gradient echo sequences in abdominal magnetic resonance imaging at 3 Tesla. Faster acquisition time without compromising image quality or diagnostic confidence was possible by using this deep learning-based reconstruction technique.
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- 2022
13. Free‐Breathing Volumetric Liver and Proton Density Fat Fraction Quantification in Pediatric Patients Using Stack‐of‐Radial <scp>MRI</scp> With Self‐Gating Motion Compensation
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Tsu-Chin Tsao, Houchun H. Hu, Xinzhou Li, Brian M. Dale, Holden H. Wu, Stephan Kannengiesser, Tess Armstrong, Vibhas S. Deshpande, Yu-Hsiu Lee, Marcel Dominik Nickel, Xiaodong Zhong, and Berthold Kiefer
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Motion compensation ,Intraclass correlation ,business.industry ,Region of interest ,Self gating ,Proton density fat fraction ,Medicine ,Radiology, Nuclear Medicine and imaging ,Positive bias ,business ,Nuclear medicine ,Imaging phantom ,Free breathing - Abstract
BACKGROUND Stack-of-radial multiecho gradient-echo MRI is promising for free-breathing liver R2* quantification and may benefit children. PURPOSE To validate stack-of-radial MRI with self-gating motion compensation in phantoms, and to evaluate it in children. STUDY TYPE Prospective. PHANTOMS Four vials with different R2* driven by a motion stage. SUBJECTS Sixteen pediatric patients with suspected nonalcoholic fatty liver disease or steatohepatitis (five females, 13 ± 4 years, body mass index 29.2 ± 8.6 kg/m2 ). FIELD STRENGTH/SEQUENCES Stack-of-radial, and 2D and 3D Cartesian multiecho gradient-echo sequences at 3T. ASSESSMENT Ungated and gated stack-of-radial proton density fat fraction (PDFF) and R2* maps were reconstructed without and with self-gating motion compensation. Stack-of-radial R2* measurements of phantoms without and with motion were validated against reference 2D Cartesian results of phantoms without motion. In subjects, free-breathing stack-of-radial and reference breath-hold 3D Cartesian were acquired. Subject inclusion for statistical analysis and region of interest placement were determined independently by two observers. STATISTICAL TESTS Phantom results were fitted with a weighted linear model. Demographic differences between excluded and included subjects were tested by multivariate analysis of variance. PDFF and R2* measurements were compared using Bland-Altman analysis. Interobserver agreement was assessed by the intraclass correlation coefficient (ICC). RESULTS Ungated stack-of-radial R2* inside moving phantom vials showed a significant positive bias of 64.3 s-1 (P 0.31). Subject inclusion decisions for statistical analysis from two observers were consistent. No significant differences were found between four excluded and 12 included subjects (P = 0.14). Compared to breath-hold Cartesian, ungated and gated free-breathing stack-of-radial exhibited mean R2* differences of 18.5 s-1 and 3.6 s-1 . Mean PDFF differences were 1.1% and 1.0% for ungated and gated measurements, respectively. Interobserver agreement was excellent (ICC for PDFF = 0.99, ICC for R2* = 0.90; P
- Published
- 2020
14. Liver Iron Content Determination Using a Volumetric Breath‐Hold Gradient‐Echo Sequence With In‐Line <scp> R 2 </scp> * Calculation
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Stefan Schmidt, Meinrad Beer, Stephan Kannengießer, Lena Kneller, Holger Cario, Arthur Wunderlich, and Valeria Mauro
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education.field_of_study ,medicine.diagnostic_test ,business.industry ,Intraclass correlation ,Anemia ,Content determination ,Population ,Magnetic resonance imaging ,medicine.disease ,Correlation ,Medicine ,Liver iron ,Radiology, Nuclear Medicine and imaging ,business ,education ,Nuclear medicine ,Gradient echo - Abstract
BACKGROUND Liver iron overload is a serious condition occurring in patients requiring blood transfusions (eg, in thalassemia and different forms of anemia) or with dysfunctional iron resorption, since there is no physiological mechanism to excrete iron. Above a certain level of iron concentration, chelation therapy is indicated. To monitor therapy success, liver iron content should be assessed regularly. A noninvasive method is important for patient management. Existing MRI methods suffer from long acquisition times and cost. PURPOSE To study the correlation of liver iron content (LIC) reference values to liver R2 * determined using a 3D breath-hold multigradient echo (GRE) MRI sequence, employing accelerated acquisition by parallel imaging and in-line R2 * calculation. STUDY TYPE Prospective. POPULATION In all, 117 patients (22.1 ± 14.1 years, 66 men) suspected of iron overload. SEQUENCE GRE. FIELD STRENGTH 1.5T. ASSESSMENT For comparison, a regulatory-approved method with a considerably longer scan time was used, providing LIC reference values. Participants were divided into a calibration group (65 participants), analyzed independently by two observers, and a validation group (52 participants). STATISTICAL TESTS Linear correlation parameters were evaluated for R2 * values with LIC reference values, and for LIC determined from R2 * for validation group participants with LIC reference values. Sensitivity/specificity for clinical relevant LIC thresholds were analyzed. Interobserver variability was determined by intraclass correlation coefficient (ICC). RESULTS Interobserver agreement was excellent, with an ICC of 0.99, P
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- 2020
15. Non-invasive tumor decoding and phenotyping of cerebral gliomas utilizing multiparametric 18F-FET PET-MRI and MR Fingerprinting
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Mark A. Griswold, Vikas Gulani, Ulrich Sure, Martin Glas, Karsten H. Wrede, Stephan Kannengiesser, Lale Umutlu, Ken Herrmann, Kathy Keyvani, Mathias Nittka, Aydin Demircioglu, Marcel Gratz, Gerald Antoch, Felix Nensa, Johannes Haubold, and Michael Forsting
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medicine.medical_specialty ,IDH1 ,medicine.diagnostic_test ,business.industry ,Radiogenomics ,Brain tumor ,General Medicine ,Gold standard (test) ,medicine.disease ,030218 nuclear medicine & medical imaging ,03 medical and health sciences ,0302 clinical medicine ,030220 oncology & carcinogenesis ,Glioma ,Biopsy ,medicine ,Radiology, Nuclear Medicine and imaging ,Sampling (medicine) ,Radiology ,business ,ATRX - Abstract
The introduction of the 2016 WHO classification of CNS tumors has made the combined molecular and histopathological characterization of tumors a pivotal part of glioma patient management. Recent publications on radiogenomics-based prediction of the mutational status have demonstrated the predictive potential of imaging-based, non-invasive tissue characterization algorithms. Hence, the aim of this study was to assess the potential of multiparametric 18F-FET PET-MRI including MR fingerprinting accelerated with machine learning and radiomic algorithms to predict tumor grading and mutational status of patients with cerebral gliomas. 42 patients with suspected primary brain tumor without prior surgical or systemic treatment or biopsy underwent an 18F-FET PET-MRI examination. To differentiate the mutational status and the WHO grade of the cerebral tumors, support vector machine and random forest were trained with the radiomics signature of the multiparametric PET-MRI data including MR fingerprinting. Surgical sampling served as a gold standard for histopathological reference and assessment of mutational status. The 5-fold cross-validated area under the curve in predicting the ATRX mutation was 85.1%, MGMT mutation was 75.7%, IDH1 was 88.7%, and 1p19q was 97.8%. The area under the curve of differentiating low-grade glioma vs. high-grade glioma was 85.2%. 18F-FET PET-MRI and MR fingerprinting enable high-quality imaging-based tumor decoding and phenotyping for differentiation of low-grade vs. high-grade gliomas and for prediction of the mutational status of ATRX, IDH1, and 1p19q. These initial results underline the potential of 18F-FET PET-MRI to serve as an alternative to invasive tissue characterization.
- Published
- 2019
16. Technical success rates and reliability of spin-echo echo-planar imaging (SE-EPI) MR elastography in patients with chronic liver disease or liver cirrhosis
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Sung Bin Park, Hyun Jeong Park, Ara Ko, Eun Sun Lee, Byung Ihn Choi, Young Youn Cho, Sang Lim Choi, and Stephan Kannengiesser
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Adult ,Liver Cirrhosis ,Male ,medicine.medical_specialty ,Cirrhosis ,Chronic liver disease ,030218 nuclear medicine & medical imaging ,03 medical and health sciences ,Liver disease ,0302 clinical medicine ,Ascites ,medicine ,Humans ,Radiology, Nuclear Medicine and imaging ,Expiration ,Retrospective Studies ,medicine.diagnostic_test ,Echo-Planar Imaging ,business.industry ,Liver Diseases ,Ultrasound ,Reproducibility of Results ,Magnetic resonance imaging ,General Medicine ,Middle Aged ,medicine.disease ,Liver ,030220 oncology & carcinogenesis ,Female ,Elastography ,Radiology ,medicine.symptom ,business - Abstract
To determine the technical success rates of MR elastography (MRE) according to established gradient-recalled echo (GRE) and spin-echo echo-planar imaging (SE-EPI) sequences and to compare liver stiffness (LS) values between the sequences during expiratory and inspiratory phases in patients with chronic liver disease or liver cirrhosis.One hundred and eight patients who underwent MRE were included in this retrospective study. MRE was performed at 3 T based on both sequences during expiration as well as inspiration. Technical failure of MRE was determined if there was no pixel value with a confidence index higher than 95% and/or no apparent shear waves imaged. LS measurements were performed using free-drawing region of interest. To evaluate clinical factors related to the technical success rate of MRE, we assessed etiology of liver disease, ascites, body habitus, iron deposition, and liver morphology of patients. Statistical analysis was performed with the Wilcoxon test, Bland-Altman plot, independent t test, Mann-Whitney test, and McNemar test.The technical success rate of MRE in SE-EPI was significantly higher than that of GRE (98.1% vs. 80.7%, p0.0001). On the basis of univariate analysis, height, weight, and BMI were significantly associated with failure of MRE (p0.05). There was no significant difference in LS values between GRE and SE-EPI (2.82 kPa vs. 2.92 kPa (p0.05)). However, the LS values were significantly higher during inspiration than expiration with both GRE and SE-EPI (p0.0001).MRE in SE-EPI during expiratory breath-hold can be used as a reliable examination to evaluate liver fibrosis.• The technical success rate of MR elastography in spin-echo echo-planar imaging (SE-EPI) was significantly higher than that in gradient-recalled echo (GRE) during both the inspiratory and expiratory phases. • Liver stiffness values were significantly higher during inspiration than during expiration in both GRE and SE-EPI. • MR elastography in SE-EPI during expiratory breath-hold can be used as a reliable examination in patients with liver fibrosis.
- Published
- 2019
17. Effect of respiratory motion on free‐breathing 3D stack‐of‐radial liver relaxometry and improved quantification accuracy using self‐gating
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Holden H. Wu, Stephan Kannengiesser, Tess Armstrong, Li Pan, Vibhas S. Deshpande, Berthold Kiefer, Xiaodong Zhong, Marcel Dominik Nickel, and Brian M. Dale
- Subjects
Physics ,Mixed model ,Relaxometry ,Motion compensation ,Self gating ,Attenuation ,Respiratory motion ,030218 nuclear medicine & medical imaging ,03 medical and health sciences ,0302 clinical medicine ,Nuclear magnetic resonance ,Stack (abstract data type) ,Radiology, Nuclear Medicine and imaging ,030217 neurology & neurosurgery ,Free breathing - Abstract
Purpose To develop an accurate free-breathing 3D liver R 2 ∗ mapping approach and to evaluate it in vivo. Methods A free-breathing multi-echo stack-of-radial sequence was applied in 5 normal subjects and 6 patients at 3 Tesla. Respiratory motion compensation was implemented using the inherent self-gating signal. A breath-hold Cartesian acquisition was the reference standard. Proton density fat fraction and R 2 ∗ were measured and compared between radial and Cartesian methods using Bland-Altman plots. The normal subject results were fitted to a linear mixed model (P Results Free-breathing stack-of-radial without self-gating exhibited signal attenuation in echo images and artifactually elevated apparent R 2 ∗ values. In the Bland-Altman plots of normal subjects, compared to breath-hold Cartesian, free-breathing stack-of-radial acquisitions of 22, 30, 36, and 44 slices, had mean R 2 ∗ differences of 27.4, 19.4, 10.9, and 14.7 s-1 with 800 radial views, and they had 18.4, 11.9, 9.7, and 27.7 s-1 with 404 views, which were reduced to 0.4, 0.9, -0.2, and -0.7 s-1 and to -1.7, -1.9, -2.1, and 0.5 s-1 with self-gating, respectively. No substantial proton density fat fraction differences were found. The linear mixed model showed free-breathing radial R 2 ∗ results without self-gating were significantly biased by 17.2 s-1 averagely (P = .002), which was eliminated with self-gating (P = .930). Proton density fat fraction results were not different (P > .234). For patients, Bland-Altman plots exhibited mean R 2 ∗ differences of 14.4 and 0.1 s-1 for free-breathing stack-of-radial without self-gating and with self-gating, respectively, but no substantial proton density fat fraction differences. Conclusion The proposed self-gating method corrects the respiratory motion bias and enables accurate free-breathing stack-of-radial quantification of liver R 2 ∗ .
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- 2019
18. Accelerated Three-dimensional T2-Weighted Turbo-Spin-Echo Sequences with Inner-Volume Excitation and Iterative Denoising in the Setting of Pelvis MRI at 1.5T: Impact on Image Quality and Lesion Detection
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Haidara Almansour, Elisabeth Weiland, Bernd Kuehn, Stephan Kannengiesser, Sebastian Gassenmaier, Judith Herrmann, Rüdiger Hoffmann, Ahmed E. Othman, and Saif Afat
- Subjects
Radiology, Nuclear Medicine and imaging - Abstract
To investigate image quality and rate of lesion detection in a novel three-dimensional T2-weighted turbo-spin-echo sequence with inner-volume excitation (zoomed imaging) and iterative denoising processing in pelvic MRI at 1.5T. Two-dimensional T2-weighted turbo-spin-echo sequences were used as the clinical reference standard (2D-T2-TSE).This is a prospective study of patients with various pelvic pathologies. Each patient underwent standard 2D-T2-TSE in three planes with two-fold acceleration as well as a single three-dimensional T2-TSE in the sagittal plane with four-fold acceleration known as Sampling-Perfection-with-Application-optimized-Contrast-using-different-flip-angle-Evolutions (3D-T2-SPACE). The 3D-T2-SPACE images were reconstructed in three orthogonal planes at a slice thickness of 2 mm (vs. 2D-T2-TSE at 4 mm). Two radiologists conducted a qualitative image analysis on standard 2D-T2-TSE and multiplanar reconstructed 3D-T2-SPACE images. These parameters were compared and inter-reader agreement was computed. Furthermore, each reader documented the observed lesions of various pelvic organs. The rate of lesion detection was compared between readers and sequences. Inter-reader and inter-sequence agreement were computed.Forty patients (25 females) were included. Mean patient age was 58 ± 13 years. 3D-T2-SPACE enabled an approximate 22% reduction of acquisition time and 50% of reconstructed slice thickness. 3D-T2-SPACE showed fewer artifacts than 2D-T2-TSE (p0.001). However, 2D-T2-TSE was rated to have significantly higher signal intensity than 3D-T2-SPACE (p0.001). There were no significant differences between the two sequences regarding all other parameters. Inter-reader agreement regarding image quality parameters was substantial (Kappa = 0.772). For all analyzed pelvic anatomic structures, inter-reader and inter-sequence agreement for lesion detection was excellent (Kappa0.80).3D-T2-SPACE with the inner-volume excitation and iterative denoising is clinically feasible at 1.5 T, enabling faster imaging, thinner slices, and significant reduction of artifacts. Despite that signal intensity was inferior in the SPACE images, overall image quality, diagnostic confidence and lesion detection were not compromised. This prospective study sets the stage for further clinical implementation and future investigations tailored to specific indications in pelvis MRI.
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- 2021
19. Free-breathing MR elastography of the lungs: An in vivo study
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Yevgeniya Gokun, Josef Pfeuffer, Arunark Kolipaka, Faisal Fakhouri, and Stephan Kannengiesser
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Male ,Article ,medicine ,Humans ,Radiology, Nuclear Medicine and imaging ,Lung volumes ,Lung ,Tidal volume ,Reproducibility ,medicine.diagnostic_test ,business.industry ,Echo-Planar Imaging ,Stiffness ,Reproducibility of Results ,Repeatability ,respiratory system ,Magnetic Resonance Imaging ,respiratory tract diseases ,body regions ,Concordance correlation coefficient ,medicine.anatomical_structure ,Elasticity Imaging Techniques ,Female ,Elastography ,medicine.symptom ,business ,Nuclear medicine - Abstract
PURPOSE Lung stiffness alters with many diseases; therefore, several MR elastography (MRE) studies were performed earlier to investigate the stiffness of the right lung during breathhold at residual volume and total lung capacity. The aims of this study were 1) to estimate shear stiffness of the lungs using MRE under free breathing and demonstrate the measurements' repeatability and reproducibility, and 2) to compare lung stiffness under free breathing to breathhold and as a function of age and gender. METHODS Twenty-five healthy volunteers were scanned on a 1.5 Tesla MRI scanner. Spin-echo dual-density spiral and a spin-echo EPI MRE sequences were used to measure shear stiffness of the lungs during free breathing and breathhold at midpoint of tidal volume, respectively. Concordance correlation coefficient and Bland-Altman analyses were performed to determine the repeatability and reproducibility of the spin-echo dual-density spiral-derived shear stiffness. Repeated measures analyses of variances were used to investigate differences in shear stiffness between spin-echo dual-density spiral and spin-echo EPI, right and left lungs, males and females, and different age groups. RESULTS Free-breathing MRE sequence was highly repeatable and reproducible (concordance correlation coefficient > 0.86 for both lungs). Lung stiffness was significantly lower in breathhold than in free breathing (P < .001), which can be attributed to potential stress relaxation of lung parenchyma or breathhold inconsistencies. However, there was no significant difference between different age groups (P = .08). The left lung showed slightly higher stiffness values than the right lung (P = .14). There is no significant difference in lung stiffness between genders. CONCLUSION This study demonstrated the feasibility of free-breathing lung MRE with excellent repeatability and reproducibility. Stiffness changes with age and during the respiratory cycle. However, gender does not influence lungs stiffness.
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- 2021
20. MR elastography of liver at 3 Tesla: comparison of gradient-recalled echo (GRE) and spin-echo (SE) echo-planar imaging (EPI) sequences and agreement across stiffness measurements
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Justin M. Ream, Matthias Fenchel, Chenyang Zhan, Krishna Shanbhogue, Stephan Kannengiesser, and Hersh Chandarana
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Liver Cirrhosis ,Male ,Biopsy ,Urology ,Liver fibrosis ,Sensitivity and Specificity ,Article ,030218 nuclear medicine & medical imaging ,Diagnosis, Differential ,03 medical and health sciences ,Liver disease ,0302 clinical medicine ,Gradient recalled echo ,polycyclic compounds ,medicine ,Humans ,Radiology, Nuclear Medicine and imaging ,Echo-planar imaging ,Reproducibility ,Radiological and Ultrasound Technology ,medicine.diagnostic_test ,Echo-Planar Imaging ,business.industry ,Liver Diseases ,Gastroenterology ,Reproducibility of Results ,Stiffness ,Middle Aged ,medicine.disease ,Magnetic Resonance Imaging ,030220 oncology & carcinogenesis ,Spin echo ,Elasticity Imaging Techniques ,Female ,Elastography ,medicine.symptom ,Nuclear medicine ,business - Abstract
PURPOSE: To compare 2D gradient-recalled echo (GRE) and 2D spin-echo (SE) echo-planar imaging (EPI) MR elastography (MRE) for measurement of hepatic stiffness in adult patients with known or suspected liver disease at 3 Tesla. MATERIALS AND METHODS: Three hundred and eighty-seven consecutive patients underwent MRE of the liver at 3 Tesla with 2D-GRE and 2D-SE-EPI sequences. ‘Mean liver stiffness (LS)’ calculated by averaging 3 ROIs in the right lobe, ‘Maximum LS’ calculated by an ROI in the right lobe; and ‘Freehand LS’ calculated by an ROI in the entire liver were measured by two independent readers. Inter-observer and inter-class variability in stiffness measurements were assessed. Stiffness values were correlated with degree of liver fibrosis (METAVIR scores) in 97 patients who underwent biopsy. The diagnostic performance was compared by a receiver-operating characteristic analysis. RESULTS: The technical failure rate was 2.8% for 2D-SE-EPI (11/387) and 4.1% for 2D-GRE (16/387, 9 had R(2)* > 80 s(−1) indicating iron overload). There is high reproducibility for both GRE and SE-EPI variants (ICC = 0.84–0.94 for both GRE and SE-EPI MRE). The highest sensitivity, specificity, and accuracy of differentiating mild fibrosis (F0–F2) from advanced fibrosis (F3–F4) are 0.84 (GRE Freehand measurement), 0.92 (GRE Maximum stiffness measurement), and 0.88 (GRE Freehand measurement), respectively. CONCLUSIONS: High intra-class correlation and intra-reader correlation are seen on measured hepatic stiffness for both 2D-GRE and 2D-SE-EPI MRE. 2D-SE-EPI has lower failure rate. Diagnostic performance of both sequences is equivalent, with highest sensitivity for 2D-GRE Freehand stiffness measurement, and highest specificity 2D-GRE Maximum stiffness measurement.
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- 2019
21. Verbesserung der Bildqualität bei der dynamischen kontrastverstärkten Gradienten-Echo-Magnetresonanztomographie des Abdomens durch iteratives Denoising und Edge Enhancement
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Sebastian Gassenmaier, Saif Afat, Ahmed E. Othman, Rüdiger Hoffmann, Ferdinand Seith, Stephan Kannengiesser, Judith Herrmann, and Dominik Nickel
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- 2021
22. Image Quality Improvement of Dynamic Contrast-Enhanced Gradient Echo Magnetic Resonance Imaging by Iterative Denoising and Edge Enhancement
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Dominik Nickel, Ferdinand Seith, Rüdiger Hoffmann, Stephan Kannengiesser, Ahmed E. Othman, Judith Herrmann, Sebastian Gassenmaier, and Saif Afat
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Image quality ,Noise reduction ,media_common.quotation_subject ,Contrast Media ,030218 nuclear medicine & medical imaging ,Breath Holding ,03 medical and health sciences ,0302 clinical medicine ,Contrast (vision) ,Medicine ,Humans ,Radiology, Nuclear Medicine and imaging ,media_common ,Retrospective Studies ,medicine.diagnostic_test ,business.industry ,Magnetic resonance imaging ,General Medicine ,Edge enhancement ,Image Enhancement ,Magnetic Resonance Imaging ,Quality Improvement ,Noise ,Dynamic contrast ,Nuclear medicine ,business ,030217 neurology & neurosurgery ,Algorithms ,Gradient echo - Abstract
OBJECTIVES The aim of this study was to investigate the impact of a novel edge enhancement and iterative denoising algorithm in 1.5-T T1-weighted dynamic contrast-enhanced (DCE) gradient echo (GRE) magnetic resonance imaging of the abdomen on image quality, noise levels, diagnostic confidence, and lesion detectability. MATERIALS AND METHODS Fifty patients who underwent a clinically indicated magnetic resonance imaging with DCE imaging of the abdomen between June and August 2020 were included in this retrospective, monocentric, institutional review board-approved study. For DCE imaging, a series of 3 volume interpolated breath-hold examinations (VIBEs) was performed. The raw data of all DCE imaging studies were processed twice, once using standard reconstruction (DCES) and again using an edge enhancement and iterative denoising approach (DCEDE). All imaging studies were randomly reviewed by 2 radiologists independently regarding noise levels, arterial contrast, sharpness of vessels, overall image quality, and diagnostic confidence using a Likert scale ranging from 1 to 4, with 4 being the best. Furthermore, lesion detectability was evaluated using the same ranking system. RESULTS All 50 imaging studies were successfully reconstructed with both methods. Interreader agreement (Cohen κ) was substantial to perfect for both readers. Arterial contrast and sharpness of vessels were rated superior by both readers with a median of 4 in DCEDE versus a median of 3 in DCES (P < 0.001). Furthermore, noise levels as well as overall image quality were rated higher with a median of 4 in DCEDE compared with a median of 3 in DCES (P < 0.001). Lesion detectability was evaluated to be superior in DCEDE with a median of 4 versus DCES with a median of 3 (P < 0.001). Consequently, diagnostic confidence was also rated to be superior in DCEDE with a median of 4 versus DCES with a median of 3 (P < 0.001). CONCLUSIONS Iterative denoising and edge enhancement are feasible in DCE imaging of the abdomen providing superior arterial contrast, noise levels, and overall image quality. Furthermore, lesion detectability and diagnostic confidence were significantly improved using this novel reconstruction method. Further reduction of acquisition time might be possible via reduction of increased noise levels using this presented method.
- Published
- 2021
23. Deep Learning-Based Superresolution Reconstruction for Upper Abdominal Magnetic Resonance Imaging: An Analysis of Image Quality, Diagnostic Confidence, and Lesion Conspicuity
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Rüdiger Hoffmann, Sebastian Gassenmaier, Dominik Nickel, Saif Afat, Haidara Almansour, Jakob Weiss, Stephan Kannengiesser, and Ahmed E. Othman
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Deblurring ,Magnetic Resonance Spectroscopy ,medicine.diagnostic_test ,Post hoc ,Image quality ,business.industry ,Deep learning ,Contrast Media ,Magnetic resonance imaging ,General Medicine ,Image Enhancement ,Superresolution ,Magnetic Resonance Imaging ,Lesion ,Precontrast ,Deep Learning ,Abdomen ,medicine ,Humans ,Radiology, Nuclear Medicine and imaging ,Artificial intelligence ,medicine.symptom ,business ,Nuclear medicine ,Artifacts - Abstract
The aim of this study was to investigate the impact of a deep learning-based superresolution reconstruction technique for T1-weighted volume-interpolated breath-hold examination (VIBESR) on image quality in comparison with standard VIBE images (VIBESD).Between May and August 2020, a total of 46 patients with various abdominal pathologies underwent contrast-enhanced upper abdominal VIBE magnetic resonance imaging (MRI) at 1.5 T. After data acquisition, the precontrast and postcontrast T1-weighted VIBE raw data were processed by a deep learning-based prototype algorithm for deblurring and denoising the images as well as for enhancing their sharpness (VIBESR). In a randomized and blinded manner, 2 radiologists independently analyzed the image data sets using the unprocessed images VIBESD as a standard reference. Outcome measures were as follows: overall image quality, anatomic clarity of organ borders, sharpness of vessels, artifacts, noise, and diagnostic confidence. All ratings were performed on an ordinal 4-point Likert scale. If the MRI examination encompassed a hepatic lesion, the maximum diameter of the largest hepatic lesion was quantified, and lesion sharpness and conspicuity were evaluated on an ordinal 4-point Likert scale. In addition, a post hoc regression analysis for lesion evaluation was computed. Finally, interrater/intrarater agreement was analyzed.The overall image quality, anatomic clarity of organ borders, and sharpness of vessels in both precontrast and postcontrast images were rated significantly higher in VIBESR than in VIBESD (P0.001). Similarly, diagnostic confidence was higher in VIBESR than in VIBESD (P0.001). Furthermore, VIBESR images were rated to have significantly less noise and fewer artifacts in comparison with VIBESD (P0.001). The interreader agreement was substantial with a Cohen κ of 0.72 for the precontrast analysis and a κ of 0.74 for the postcontrast analysis. A total of 28 hepatic lesions were analyzed. For both readers, lesion sharpness and conspicuity were rated significantly better in VIBESR than in VIBESD in both the precontrast and postcontrast data sets (P0.01), which was consistent with the post hoc regression analysis (for every 1-point increase in sharpness/conspicuity, the odds ratio revealed a positive relation with VIBESR of 13-fold to 17-fold in comparison with VIBESD; P0.001). In terms of lesion size, there was no significant difference between the precontrast VIBESD and VIBESR or between the postcontrast VIBESD and VIBESR for both readers. Similarly, there was an excellent interreader agreement regarding lesion size (intraclass correlation coefficient,0.9).The data-driven superresolution reconstruction (VIBESR) is clinically feasible for precontrast and postcontrast upper abdominal VIBE MRI, providing improved image quality, diagnostic confidence, and lesion conspicuity compared with standard VIBESD images.
- Published
- 2021
24. Effect of hepatic steatosis on native T1 mapping of 3T magnetic resonance imaging in the assessment of T1 values for patients with non-alcoholic fatty liver disease
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Ji Hye Huh, Sang Baek Koh, Jong Han Lee, Jang Young Kim, Jae Seung Chang, Kyu Sang Park, Marcel Dominik Nickel, Seong Hee Kang, Moon Young Kim, Jhii Hyun Ahn, Stephan Kannengiesser, and Jeong-Sik Yu
- Subjects
medicine.medical_specialty ,Population ,Biomedical Engineering ,Biophysics ,Gastroenterology ,030218 nuclear medicine & medical imaging ,Cohort Studies ,03 medical and health sciences ,0302 clinical medicine ,Non-alcoholic Fatty Liver Disease ,Internal medicine ,Nonalcoholic fatty liver disease ,Medicine ,Humans ,Radiology, Nuclear Medicine and imaging ,Prospective Studies ,education ,education.field_of_study ,medicine.diagnostic_test ,business.industry ,Fatty liver ,Magnetic resonance imaging ,medicine.disease ,Magnetic Resonance Imaging ,Magnetic resonance elastography ,Liver ,Steatosis ,business ,Hepatic fibrosis ,Body mass index ,030217 neurology & neurosurgery - Abstract
This study investigated whether T1 values in native T1 mapping of 3T magnetic resonance imaging (MRI) of the liver were affected by the fatty component.This prospective study involved 340 participants from a population-based cohort study between May 8, 2018 and August 8, 2019. Data obtained included: (1) hepatic stiffness according to magnetic resonance elastography (MRE); (2) T1 value according to T1 mapping; (3) fat fraction and iron concentration from multi-echo Dixon; and (4) clinical indices of hepatic steatosis including body mass index, waist circumference, history of diabetes, aspartate aminotransferase, alanine aminotransferase, gamma-glutamyl transpeptidase, and triglycerides. The correlations between T1 value and fat fraction, and between T1 value and liver stiffness were assessed using Pearson's correlation coefficient. The independent two-sample t-test was used to evaluate the differences in T1 values according to the presence or absence of hepatic steatosis, and the one-way analysis of variance was used to evaluate the difference in T1 value by grading of hepatic steatosis according to MRI-based proton density fat fraction (PDFF). In addition, univariate and multivariate linear regression analyses were performed to determine whether other variables influenced the T1 value.T1 value showed a positive correlation with the fat fraction obtained from PDFF (r = 0.615, P 0.001) and with the liver stiffness obtained from MRE (r = 0.370, P 0.001). Regardless of the evaluation method, the T1 value was significantly increased in subjects with hepatic steatosis (P 0.001). When comparing hepatic steatosis grades based on MRI-PDFF, the mean T1 values were significantly different in all grades, and the T1 value tended to increase as the grade increased (P 0.001, P for trend0.001). On multiple linear regression analysis, the T1 value was influenced by MRI-PDFF, calculated liver iron concentration, liver stiffness, and serum aspartate aminotransferase level.The T1 value obtained by current T1 mapping of 3T MRI was affected by the liver fat component and several other factors such as liver stiffness, iron concentration, and inflammation.
- Published
- 2020
25. Magnetic resonance elastography for estimating in vivo stiffness of the abdominal aorta using cardiac‐gated spin‐echo echo‐planar imaging: a feasibility study
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Stephan Kannengiesser, Brian Raterman, Arunark Kolipaka, Ning Jin, Richard D. White, and Huiming Dong
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Coefficient of variation ,Cardiac-Gated Imaging Techniques ,Signal-To-Noise Ratio ,030218 nuclear medicine & medical imaging ,03 medical and health sciences ,Vascular Stiffness ,0302 clinical medicine ,Reference Values ,In vivo ,medicine.artery ,medicine ,Humans ,Radiology, Nuclear Medicine and imaging ,Aorta, Abdominal ,Spectroscopy ,Reproducibility ,Echo-Planar Imaging ,business.industry ,Respiration ,Abdominal aorta ,Reproducibility of Results ,Magnetic Resonance Imaging ,Magnetic resonance elastography ,Concordance correlation coefficient ,Spin echo ,Elasticity Imaging Techniques ,Feasibility Studies ,Molecular Medicine ,Aortic stiffness ,business ,Nuclear medicine ,030217 neurology & neurosurgery - Abstract
Introduction Magnetic resonance elastography (MRE)-derived aortic stiffness is a potential biomarker for multiple cardiovascular diseases. Currently, gradient-recalled echo (GRE) MRE is a widely accepted technique to estimate aortic stiffness. However, multi-slice GRE MRE requires multiple breath-holds (BHs), which can be challenging for patients who cannot consistently hold their breath. The aim of this study was to investigate the feasibility of a multi-slice spin-echo echo-planar imaging (SE-EPI) MRE sequence for quantifying in vivo aortic stiffness using a free-breathing (FB) protocol and a single-BH protocol. Method On Scanner 1, 25 healthy subjects participated in the validation of FB SE-EPI against FB GRE. On Scanner 2, another 15 healthy subjects were recruited to compare FB SE-EPI with single-BH SE-EPI. Among all volunteers, five participants were studied on both scanners to investigate the inter-scanner reproducibility of FB SE-EPI aortic MRE. Bland-Altman analysis, Lin's concordance correlation coefficient (LCCC) and coefficient of variation (COV) were evaluated. The phase-difference signal-to-noise ratios (PD SNR) were compared. Results Aortic MRE using FB SE-EPI and FB GRE yielded similar stiffnesses (paired t-test, P = 0.19), with LCCC = 0.97. The FB SE-EPI measurements were reproducible (intra-scanner LCCC = 0.96) and highly repeatable (LCCC = 0.99). The FB SE-EPI MRE was also reproducible across different scanners (inter-scanner LCCC = 0.96). Single-BH SE-EPI scans yielded similar stiffness to FB SE-EPI scans (LCCC = 0.99) and demonstrated a low COV of 2.67% across five repeated measurements. Conclusion Multi-slice SE-EPI aortic MRE using an FB protocol or a single-BH protocol is reproducible and repeatable with advantage over multi-slice FB GRE in reducing acquisition time. Additionally, FB SE-EPI MRE provides a potential alternative to BH scans for patients who have challenges in holding their breath.
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- 2020
26. Liver Iron Content Determination Using a Volumetric Breath-Hold Gradient-Echo Sequence With In-Line R
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Arthur P, Wunderlich, Stefan A, Schmidt, Valeria, Mauro, Lena, Kneller, Stephan, Kannengießer, Meinrad, Beer, and Holger, Cario
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Male ,Iron Overload ,Liver ,Iron ,Humans ,Prospective Studies ,Magnetic Resonance Imaging - Abstract
Liver iron overload is a serious condition occurring in patients requiring blood transfusions (eg, in thalassemia and different forms of anemia) or with dysfunctional iron resorption, since there is no physiological mechanism to excrete iron. Above a certain level of iron concentration, chelation therapy is indicated. To monitor therapy success, liver iron content should be assessed regularly. A noninvasive method is important for patient management. Existing MRI methods suffer from long acquisition times and cost.To study the correlation of liver iron content (LIC) reference values to liver RProspective.In all, 117 patients (22.1 ± 14.1 years, 66 men) suspected of iron overload.GRE.1.5T.For comparison, a regulatory-approved method with a considerably longer scan time was used, providing LIC reference values. Participants were divided into a calibration group (65 participants), analyzed independently by two observers, and a validation group (52 participants).Linear correlation parameters were evaluated for RInterobserver agreement was excellent, with an ICC of 0.99, P 0.001. Good correlation (RMRI acquisition times for determination of LIC can be significantly reduced by the use of comprehensive in-line R1 TECHNICAL EFFICACY STAGE: 2.
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- 2020
27. Simultaneous Multislice Diffusion-Weighted Imaging of the Kidneys at 3 T
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Stephan Kannengiesser, John N. Morelli, Dominik Nickel, Philipp Riffel, UIrike I Attenberger, Andrej Tavakoli, Julia Krammer, Stefan O. Schoenberg, Johannes Budjan, and Alto Stemmer
- Subjects
Male ,Wilcoxon signed-rank test ,Image quality ,Signal-To-Noise Ratio ,Kidney ,030218 nuclear medicine & medical imaging ,Cohort Studies ,03 medical and health sciences ,0302 clinical medicine ,medicine ,Effective diffusion coefficient ,Humans ,Radiology, Nuclear Medicine and imaging ,cardiovascular diseases ,Prospective Studies ,Prospective cohort study ,Retrospective Studies ,medicine.diagnostic_test ,business.industry ,Echo-Planar Imaging ,Reproducibility of Results ,Magnetic resonance imaging ,General Medicine ,Middle Aged ,Diffusion Magnetic Resonance Imaging ,Signal-to-noise ratio (imaging) ,Feasibility Studies ,Female ,Kidney Diseases ,business ,Nuclear medicine ,Artifacts ,030217 neurology & neurosurgery ,Student's t-test ,Diffusion MRI - Abstract
PURPOSE The aim of this study was to compare respiratory-triggered diffusion-weighted imaging with simultaneous-multislice acceleration (SMS-RT-DWI) to a standard free-breathing echoplanar DWI (s-DWI) for 3 T renal imaging with respect to image quality and artifacts. MATERIALS AND METHODS A total of 40 patients who had undergone renal magnetic resonance imaging were included in this retrospective analysis of a prospectively planned cohort study. All examinations were performed on a 3 T whole-body magnetic resonance system. Both s-DWI and SMS-RT-DWI were obtained and images were independently reviewed by 2 radiologists on a 5-point Likert scale with respect to overall preference and image quality, renal edge and parenchymal sharpness, cortico-medullary differentiation, and sequence-related artifacts. Furthermore, discernibility of renal lesions was assessed. The signal-to-noise ratio (SNR) was measured from SNR maps. The derived mean apparent diffusion coefficients were also compared. Qualitative parameters were assessed with the Wilcoxon rank-sum test, and quantitative parameters, with the Student t test. RESULTS Overall image quality, renal edge, and parenchymal sharpness of SMS-RT-DWI were rated as superior to s-DWI by the readers, with fewer sequence-related artifacts (P < 0.01 for all). Lesion discernibility was significantly improved for SMS-RT-DWI (P < 0.01). Both readers preferred SMS-RT-DWI to s-DWI in all cases (40/40). The acquisition time for SMS-RT-DWI was 30% shorter than for s-DWI. Mean SNR heterogeneity of SMS-RT-DWI at b = 800 s/mm was statistically significantly lower than s-DWI, whereas mean SNR was significantly higher for SMS-RT-DWI. Mean apparent diffusion coefficient values from both sequences were comparably homogeneous throughout the kidneys. CONCLUSION Simultaneous multislice DWI of the kidney at 3 T with respiratory triggering yields substantially improved image quality and lesion discernibility compared with standard single-shot echoplanar DWI with a 30% reduction in scan acquisition time.
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- 2020
28. Prospective Evaluation of an R2* Method for Assessing Liver Iron Concentration (LIC) Against FerriScan: Derivation of the Calibration Curve and Characterization of the Nature and Source of Uncertainty in the Relationship
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Stephan Kannengiesser, Marshall S. Sussman, Kevin H.M. Kuo, Richard Ward, and Kartik S Jhaveri
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Liver Iron Concentration ,Calibration curve ,Study Type ,Prospective evaluation ,030218 nuclear medicine & medical imaging ,03 medical and health sciences ,0302 clinical medicine ,Linear relationship ,Homoscedasticity ,Statistics ,Radiology, Nuclear Medicine and imaging ,Multislice ,Mathematics ,Statistical hypothesis testing - Abstract
Background FerriScan is the method-of-choice for noninvasive liver iron concentration (LIC) quantification. However, it has a number of drawbacks including cost and expediency. Purpose/hypothesis To characterize an R2*-based MRI technique that may potentially be used as an alternative to FerriScan. This was accomplished through the derivation of a calibration curve that characterized the relationship between FerriScan-derived LIC and R2*. The nature and source of uncertainty in this curve were investigated. It was hypothesized that the source of uncertainty is heterogeneity of LIC across the liver. Study type Prospective. Subjects In all, 125 patients (69 women, 56 men) undergoing chelation treatment for iron overload prospectively underwent FerriScan and R2* MRI during the same exam. Field strength/sequence Pulse sequences included 2D multislice spin-echo pulse for FerriScan, and a prototype 3D 6-echo gradient echo acquisition for R2* mapping at 1.5T. Assessment A linear calibration curve was derived from the relationship between FerriScan-derived LIC estimates and R2* through least-squares fitting. Statistical tests The nature of the uncertainty in the curve was characterized through tests of normality and homoscedasticity. The source of uncertainty was tested by comparing the magnitude of LIC variation over the FerriScan ROI to the observed uncertainty in the R2*-derived LIC estimates. Results A linear relationship between logarithmically transformed FerriScan-derived LIC and R2* (log{FerriScan-derived LIC} = 1.029 log{R2*} - 3.822) was confirmed. Uncertainty was random, with a behaviour that was normal and homoscedastic. The source of uncertainty was confirmed as iron heterogeneity across the liver. The nontransformed calibration curve was: FerriScan-derived LIC = 0.0266⋅R2*, with a constant coefficient-of-variation of 0.32. Data conclusion FerriScan and R2* techniques were found to provide equivalent quantification of LIC in this study. Any difference in accuracy or precision was at a level lower than the uncertainty caused by variation in LIC over the liver. Level of evidence 1 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2019;49:1467-1474.
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- 2018
29. Liver MR Elastography at 3 T: Agreement Across Pulse Sequences and Effect of Liver R2* on Image Quality
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Steven S. Raman, David S.K. Lu, Kang-Sun Choi, Kyung hyun Sung, Bradley D. Bolster, Ely R Felker, Holden H. Wu, Stephan Kannengiesser, and Kari Sorge
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Adult ,Liver Cirrhosis ,Male ,Adolescent ,Image quality ,030218 nuclear medicine & medical imaging ,Young Adult ,03 medical and health sciences ,0302 clinical medicine ,Nuclear magnetic resonance ,medicine ,Humans ,Radiology, Nuclear Medicine and imaging ,Aged ,Retrospective Studies ,Aged, 80 and over ,medicine.diagnostic_test ,Echo-Planar Imaging ,Pulse (signal processing) ,business.industry ,Echo (computing) ,General Medicine ,Middle Aged ,Magnetic Resonance Imaging ,Elasticity Imaging Techniques ,Female ,030211 gastroenterology & hepatology ,Elastography ,business - Abstract
The objectives of our study were to compare MR elastography (MRE) based on gradient-recalled echo (GRE) imaging with spin-echo echo-planar imaging (SEEPI) and rapid fractional (RF)-GRE MRE sequences at 3 T in terms of liver stiffness (LS) and image quality and to evaluate the effect of liver R2* on image quality.Eighty-one patients underwent 3-T liver MRE with GRE, SE-EPI, and RF-GRE sequences performed in variable order in this study. LS and ROI areas on the LS 95% confidence maps were compared among the three sequences. The relationship between liver R2* and ROI area was investigated.There was no significant difference in mean LS among the three sequences (p = 0.49). Mean ROI area was significantly larger for RF-GRE (18,213 ± 9292 [SD] mmSE-EPI-and RF-GRE-based MRE sequences provide equivalent measures of LS compared with GRE-based MRE, and both have lower technical failure rates. The RF-GRE sequence yielded the largest measurable area of LS. Among patients with iron overload, there was a trend toward larger measurable area of LS for the SE-EPI sequence.
- Published
- 2018
30. Validation of intimate correlation between visceral fat and hepatic steatosis: Quantitative measurement techniques using CT for area of fat and MR for hepatic steatosis
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Jae Young Byun, Joon-Il Choi, Stephan Kannengiesser, Soon Nam Oh, Michael Yong Park, Yohan Son, Moon Hyung Choi, Seung Eun Jung, and Sung Eun Rha
- Subjects
Adult ,Male ,medicine.medical_specialty ,Pathology ,Adolescent ,Computed tomography ,Intra-Abdominal Fat ,Critical Care and Intensive Care Medicine ,Gastroenterology ,Body Mass Index ,Correlation ,Young Adult ,03 medical and health sciences ,0302 clinical medicine ,Internal medicine ,medicine ,Humans ,Obesity ,Total fat ,Visceral fat ,Aged ,Nutrition and Dietetics ,medicine.diagnostic_test ,business.industry ,Middle Aged ,University hospital ,medicine.disease ,Magnetic Resonance Imaging ,Abdomen ct ,Fatty Liver ,Liver ,030220 oncology & carcinogenesis ,Female ,030211 gastroenterology & hepatology ,Steatosis ,Tomography, X-Ray Computed ,business - Abstract
Summary Background & aim The relationship between obesity and hepatic steatosis is well known, and there are many methods to measure obesity and severity of hepatic steatosis. Because of advances in radiologic techniques, the areas of certain body components can be measured on computed tomography (CT) while the severity of hepatic steatosis can be measured by magnetic resonance spectroscopy (MRS) with high accuracy. The aim of this study is to investigate the relationship between degree of fatty infiltration of the liver measured by MRS and body composition measured from CT images. Materials and methods We evaluated 95 potential liver donors who underwent abdomen CT and liver MRI (including MRS) between February 2014 and September 2015 in a tertiary university hospital. Body composition analysis was performed on CT images using commercial software. The areas of subcutaneous fat, visceral fat and abdominal circumference were measured automatically and the area of muscle was measured semi-automatically. The degree of hepatic steatosis was measured by MRS. Results The degree of hepatic steatosis showed a significant correlation with total fat area, visceral fat area, subcutaneous fat area, muscle area, abdominal circumference, BMI, and ratio of visceral fat to total fat. The strongest correlation was between hepatic steatosis and the area of visceral fat in all subjects ( r =0.569). Multivariate regression analysis showed that male gender and visceral fat area were significantly associated with hepatic steatosis ( P = 0.031, Conclusions The area of visceral fat has the most intimate correlation to the severity of hepatic steatosis among all significantly correlated parameters associated with body habitus. Accurate and quantitative body composition measurement and degree of hepatic steatosis can be noninvasively performed using advanced radiological techniques.
- Published
- 2018
31. Accuracy of Automated Liver Contouring, Fat Fraction, and R2* Measurement on Gradient Multiecho Magnetic Resonance Images
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Daniel Stocker, Mustafa R. Bashir, Stephan Kannengiesser, Cäcilia S. Reiner, University of Zurich, and Reiner, Cäcilia S
- Subjects
Adult ,Male ,Adolescent ,Liver volume ,610 Medicine & health ,Liver segmentation ,030218 nuclear medicine & medical imaging ,Young Adult ,03 medical and health sciences ,0302 clinical medicine ,Image Processing, Computer-Assisted ,2741 Radiology, Nuclear Medicine and Imaging ,Humans ,Medicine ,Radiology, Nuclear Medicine and imaging ,In patient ,Aged ,Retrospective Studies ,Fat fraction ,Aged, 80 and over ,Contouring ,medicine.diagnostic_test ,10042 Clinic for Diagnostic and Interventional Radiology ,business.industry ,Reproducibility of Results ,Proton density fat fraction ,Magnetic resonance imaging ,Middle Aged ,Magnetic Resonance Imaging ,Fatty Liver ,Adipose Tissue ,Liver ,Radiology Nuclear Medicine and imaging ,030220 oncology & carcinogenesis ,Female ,business ,Nuclear medicine ,Liver pathology - Abstract
OBJECTIVE: This study aimed to evaluate the performance of an automated workflow of volumetric liver proton density fat fraction (PDFFvol) and R2* quantification with automated inline liver volume (LV) segmentation. METHODS: Dual-echo and multiecho Dixon magnetic resonance images were evaluated in 74 consecutive patients (group A, PDFF < 10%; B, PDFF ≥ 10%; C, R2* ≥ 100 s; D, post-hemihepatectomy). The values of PDFFvol and R2*vol measurements across the LV were generated on multiecho images in an automated fashion based on inline liver segmentation on dual-echo images. Similar measurements were performed manually. RESULTS: Using the inline algorithm, the mis-segmented LV was highest in group D (80%). There were no significant differences between automated and manual measurements of PDFFvol. Automated R2*vol was significantly lower than manual R2*vol in group A (P = 0.004). CONCLUSIONS: Inline LV segmentation performed well in patients without and with hepatic steatosis. In cases with iron overload and post-hemihepatectomy, extrahepatic areas were erroneously included to a greater extent, with a tendency toward overestimation of PDFFvol.
- Published
- 2018
32. MR elastography in patients with suspected diffuse liver disease at 1.5T: Intraindividual comparison of gradient-recalled echo versus spin-echo echo-planar imaging sequences and investigation of potential confounding factors
- Author
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Benjamin Henninger, Christian Kremser, Michaela Plaikner, Stephan Kannengiesser, and Heinz Zoller
- Subjects
Male ,Concordance ,Correlation ,Liver disease ,medicine ,Humans ,Radiology, Nuclear Medicine and imaging ,medicine.diagnostic_test ,Echo-Planar Imaging ,business.industry ,Liver Diseases ,Confounding ,Reproducibility of Results ,General Medicine ,Middle Aged ,medicine.disease ,Magnetic Resonance Imaging ,Magnetic resonance elastography ,Liver ,Spin echo ,Elasticity Imaging Techniques ,Female ,Elastography ,Steatosis ,Nuclear medicine ,business - Abstract
Purpose To compare liver stiffness (LS) in patients with suspected diffuse liver disease between gradient-recalled-echo magnetic resonance elastography (GRE-MRE) and different spin-echo echo-planar imaging (SE-EPI-MRE) sequences and to investigate confounding factors including fat, iron, age, and sex. Method LS was measured at 1.5T using GRE-MRE, SE-EPI-MRE and short-TE-SE-EPI-MRE (hiSE-EPI-MRE) sequences and compared using Bland-Altman-plots together with concordance correlation coefficients (CCC). Success gradings were evaluated considering possible confounding factors. Results 305 patients (225 male, 80 females, mean age 51.12 years) were included. 109/305 showed hepatic iron overload, 183 hepatic steatosis. The mean difference (bias) in stiffness values between GRE-MRE and SE-EPI-MRE/hiSE-EPI-MRE was 0.15/0.2 kPa (LOA: −0.72,0.41 kPa/-0.94,0.55 kPa), between SE-EPI-MRE and hiSE-EPI-MRE 0.04 kPa (LOA: −0.62,0.53 kPa). The CCC for agreement between stiffness values for GRE-MRE and SE-EPI-MRE was 0.94 (0.92–0.95), 0.89 (0.86–0.91) for hiSE-EPI-MRE and GRE-MRE and 0.94 (0.92–0.95) for SE-EPI-MRE and hiSE-EPI-MRE. Using GRE-MRE, 72/305 showed unusable results whereby all these patients had high iron levels (mean R2*=209.7 1/s). For SE-EPI-MRE and hiSE-EPI-MRE only 10/305 and 8/305 were inconclusive respectively, corresponding to a significantly higher iron load (mean R2*= 549.2 1/s for SE-EPI-MRE and 570.7 1/s for hiSE-EPI-MRE). Concerning fat, age or sex no significant influence on success was observed for all sequences. Conclusions Good agreement of LS values was observed between GRE-MRE and SE-EPI-MRE sequences. The number of successful exams, however, was considerably lower for GRE-MRE, mainly due to iron content. Study reference number: AN5093.
- Published
- 2021
33. Comparison of spin-echo echoplanar imaging and gradient recalled echo-based MR elastography at 3 Tesla with and without gadoxetic acid administration
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Yong Seek Kim, Seung Young Seo, Ji Soo Song, and Stephan Kannengiesser
- Subjects
Adult ,Gadolinium DTPA ,Liver Cirrhosis ,Male ,Gadoxetic acid ,medicine.medical_specialty ,Cirrhosis ,Contrast Media ,Esophageal and Gastric Varices ,Risk Assessment ,030218 nuclear medicine & medical imaging ,03 medical and health sciences ,0302 clinical medicine ,polycyclic compounds ,medicine ,Humans ,Radiology, Nuclear Medicine and imaging ,Endoscopy, Digestive System ,Aged ,Neuroradiology ,Aged, 80 and over ,medicine.diagnostic_test ,Echo-Planar Imaging ,business.industry ,Ultrasound ,Reproducibility of Results ,General Medicine ,Middle Aged ,medicine.disease ,Magnetic Resonance Imaging ,Magnetic resonance elastography ,Liver ,ROC Curve ,030220 oncology & carcinogenesis ,Spin echo ,Elasticity Imaging Techniques ,Female ,Elastography ,Radiology ,business ,Varices ,medicine.drug - Abstract
To compare spin-echo echoplanar imaging (SE-EPI) and gradient recalled echo (GRE) MR elastography (MRE) at 3 T with and without gadoxetic acid administration. We included 84 patients who underwent MRE before and after gadoxetic acid administration, each time using SE-EPI and GRE sequences. Diagnostic performance for predicting clinical liver cirrhosis and high-risk oesophageal varices was assessed using the area under the receiver-operating characteristic curve (AUC). The relationships between T2* and success of MRE, and correlations of liver stiffness (LS) values between the two sequences or before and after gadoxetic acid administration, were investigated. SE-EPI-MRE resulted in a significantly lower failure rate than GRE-MRE (1.19% vs. 10.71%, P = 0.018). Increased T2* was related to higher probability of successful LS measurement (odds ratio, 1.426; P = 0.004). The AUC of SE-EPI-MRE was comparable to that of GRE-MRE for the detection of clinical liver cirrhosis (0.938 vs. 0.948, P = 0.235) and high-risk oesophageal varices (0.839 vs. 0.752, P = 0.354). LS values were not significantly different before and after gadoxetic acid administration. SE-EPI-MRE can substitute for GRE-MRE for the detection of clinical liver cirrhosis and high-risk oesophageal varices. SE-EPI-MRE is particularly useful in patients with iron deposition, with lower failure rates than GRE-MRE. • LS values are comparable between SE-EPI-MRE and GRE-MRE. • Administration of gadoxetic acid does not influence LS measurement. • The failure rate of SE-EPI-MRE is significantly lower than that of GRE-MRE.
- Published
- 2017
34. 3D Multiecho Dixon for the Evaluation of Hepatic Iron and Fat in a Clinical Setting
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Xiaodong Zhong, Werner Jaschke, Benjamin Henninger, Heinz Zoller, Stephan Kannengiesser, and Christian Kremser
- Subjects
Relaxometry ,medicine.diagnostic_test ,business.industry ,Mean age ,Magnetic resonance imaging ,030218 nuclear medicine & medical imaging ,03 medical and health sciences ,0302 clinical medicine ,030220 oncology & carcinogenesis ,Linear regression ,medicine ,Radiology, Nuclear Medicine and imaging ,Hepatic iron ,Stage (cooking) ,Nuclear medicine ,business - Abstract
Purpose To prospectively evaluate a new 3D-multiecho-Dixon (3D-ME-Dixon) sequence for the quantification of hepatic iron and fat in a clinical setting. Materials and Methods In all, 120 patients underwent 1.5T magnetic resonance imaging of the liver between December 2013 and June 2015 including the following three sequences: 3D-ME-Dixon with inline calculation of R2* and proton-density fat-fraction (PDFF) maps, single-voxel-spectroscopy (SVS), 2D multigradient-echo sequence (2D-ME-GRE). SVS and 2D-ME-GRE were used as reference for PDFF and R2*, respectively. R2*- and PDFF-values from 3D-ME-Dixon were compared with those of the reference. Linear regression analysis, Bland–Altman plots, and agreement parameters were calculated. Results In total, 103 patients were finally included (87 men and 16 women; mean age, 50.51 years); 17/120 were excluded due to fat/water-swaps or R2*-values exceeding the constraint of 400 1/s for 3D-ME-Dixon. A strong correlation (r = 0.992, P < 0.001) between R2* of 3D-ME-Dixon and the reference 2D-ME-GRE was found. Bland–Altman analysis revealed systematically lower values for 3D-ME-Dixon (16.499%). Using an adapted threshold of 57 1/s, 3D-ME-Dixon obtained a positive/negative percentage agreement (PPA/NPA) of 84.4%/91.4% for detecting hepatic iron overload. For hepatic fat the correlation between 3D-ME-Dixon and the reference SVS was strong (r = 0.957, P < 0.001); PPA/NPA was 88.3%/91.4%. Conclusion The 3D-ME-Dixon sequence is a valuable tool for the evaluation of hepatic iron and fat in a clinical setting. Fat/water-swaps remain a drawback requiring improvements to the implementation and making it necessary to have proven conventional sequences at hand in case of an eventual occurrence. Level of Evidence: 1. Technical Efficacy: Stage 2 J. MAGN. RESON. IMAGING 2017;46:793–800
- Published
- 2017
35. Differentiation of focal indeterminate marrow abnormalities with multiparametric MRI
- Author
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Jun Seung Baik, Yang Guk Chung, Sun Ki Kim, Seung Han Shin, Won-Hee Jee, Stephan Kannengiesser, Chang-Woo Chun, Chan Kwon Jung, YoHan Sohn, and Joon-Yong Jung
- Subjects
medicine.medical_specialty ,medicine.diagnostic_test ,Receiver operating characteristic ,business.industry ,Intraclass correlation ,Magnetic resonance imaging ,030218 nuclear medicine & medical imaging ,Intensity (physics) ,03 medical and health sciences ,0302 clinical medicine ,medicine ,Effective diffusion coefficient ,Radiology, Nuclear Medicine and imaging ,Radiology ,Stage (cooking) ,Indeterminate ,business ,Nuclear medicine ,030217 neurology & neurosurgery ,Intravoxel incoherent motion - Abstract
PURPOSE To explore magnetic resonance imaging (MRI) parameters from intravoxel incoherent motion diffusion-weighted imaging (IVIM-DWI), multiecho Dixon imaging (ME-Dixon), and dynamic contrast-enhanced imaging (DCE) for differentiating focal indeterminate marrow abnormalities MATERIALS AND METHODS: Forty-two patients with 14 benign and 28 malignant focal marrow abnormalities were included. The following were independently analyzed by two readers: signal intensity (SI), contour, and margin on conventional MR images; SI on b-800 images (SIb-800 ), apparent diffusion coefficient (ADC), IVIM parameters (Dslow, Dfast , and f), fat fraction (Ff), and DCE parameters (time-to-signal intensity curve pattern, iAUC, Ktrans , kep , and ve ). The MR characteristics and parameters from benign and malignant lesions were compared with a chi-squared test and the Mann-Whitney U-test, respectively. The area under receiver operating characteristic (ROC) curves (AUC) of each sequence were also compared. Interobserver agreements were assessed with Cohen's κ, and intraclass correlation coefficient (ICC). RESULTS ADC, Dslow , and Ff demonstrated a significant difference between benign and malignant marrow abnormalities for both readers (P < 0.001). SIb-800 and perfusion-related parameters from IVIM-DWI and DCE were not significantly different between the two groups (P = 0.145, 0.439, and 0.337 for reader 1, P = 0.378, 0.368, and 0.343 for reader 2, respectively). The AUCs of ADC, Dslow , and Ff were significantly higher for differentiating indeterminate marrow abnormalities in both readers (P < 0.001). Interobserver agreements were substantial in SIb-800 , and ICCs were almost perfect for ADC, Dslow , f, and Ff, and substantial for iAUC, kep , Ktrans , ve , and Dfast . CONCLUSION ADC, Dslow , and Ff may provide information for differentiating focal indeterminate abnormalities. LEVEL OF EVIDENCE 3 Technical Efficacy: Stage 2 J. MAGN. RESON. IMAGING 2017;46:49-60.
- Published
- 2016
36. Correlation between incidental fat deposition in the liver and pancreas in asymptomatic individuals
- Author
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Pegah Khoshpouri, Mounes Aliyari Ghasabeh, Xiaodong Zhong, Mohammadreza Shaghaghi, Stephan Kannengiesser, Li Pan, Pallavi Pandy, Ankur Pandy, and Ihab R. Kamel
- Subjects
In vivo magnetic resonance spectroscopy ,Adult ,Male ,medicine.medical_specialty ,Magnetic Resonance Spectroscopy ,Urology ,Fat quantification ,Asymptomatic ,Cohort Studies ,Reference Values ,Internal medicine ,medicine ,Living Donors ,Humans ,Radiology, Nuclear Medicine and imaging ,Prospective Studies ,Pancreas ,Incidental Findings ,Radiological and Ultrasound Technology ,business.industry ,Fatty liver ,Gastroenterology ,Reproducibility of Results ,Hepatology ,medicine.disease ,Single sequence ,Magnetic Resonance Imaging ,medicine.anatomical_structure ,Adipose Tissue ,Liver ,Female ,Steatohepatitis ,medicine.symptom ,Nuclear medicine ,business - Abstract
To explore the utility of two different fat quantification methods in the liver and pancreas and to test the accuracy of multi-echo Dixon as a single sequence in detecting early stage of fat deposition. 58 healthy potential liver donors underwent abdominal 3T MRI, prospectively. Single-voxel MR Spectroscopy (MRS), dual-echo Dixon, and multi-echo Dixon were performed. Two independent readers obtained proton density fat fraction (PDFF) of the liver and pancreas by placing ROIs on the 2 Dixon sequences. Correlation between the two PDFF measurements was assessed in the liver and pancreas. Values in the liver were also compared to those obtained by MRS. PDFF in the liver was 6.3 ± 4.2%, 5.5 ± 3.9%, and 5.1 ± 4.1% by MRS, dual-echo Dixon, and multi-echo Dixon, respectively. Dual-echo Dixon and multi-echo Dixon showed good correlation in PDFF quantification of the liver (r = 0.82, p
- Published
- 2019
37. Non-invasive tumor decoding and phenotyping of cerebral gliomas utilizing multiparametric
- Author
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Johannes, Haubold, Aydin, Demircioglu, Marcel, Gratz, Martin, Glas, Karsten, Wrede, Ulrich, Sure, Gerald, Antoch, Kathy, Keyvani, Mathias, Nittka, Stephan, Kannengiesser, Vikas, Gulani, Mark, Griswold, Ken, Herrmann, Michael, Forsting, Felix, Nensa, and Lale, Umutlu
- Subjects
Brain Neoplasms ,Positron-Emission Tomography ,Humans ,Tyrosine ,Glioma ,Magnetic Resonance Imaging - Abstract
The introduction of the 2016 WHO classification of CNS tumors has made the combined molecular and histopathological characterization of tumors a pivotal part of glioma patient management. Recent publications on radiogenomics-based prediction of the mutational status have demonstrated the predictive potential of imaging-based, non-invasive tissue characterization algorithms. Hence, the aim of this study was to assess the potential of multiparametric42 patients with suspected primary brain tumor without prior surgical or systemic treatment or biopsy underwent anThe 5-fold cross-validated area under the curve in predicting the ATRX mutation was 85.1%, MGMT mutation was 75.7%, IDH1 was 88.7%, and 1p19q was 97.8%. The area under the curve of differentiating low-grade glioma vs. high-grade glioma was 85.2%.
- Published
- 2019
38. Detection of hepatic steatosis and iron content at 3 Tesla: comparison of two-point Dixon, quantitative multi-echo Dixon, and MR spectroscopy
- Author
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Sonja Olsen, Krishna Shanbhogue, Hoi Cheung Zhang, Hersh Chandarana, Chenyang Zhan, and Stephan Kannengiesser
- Subjects
In vivo magnetic resonance spectroscopy ,Adult ,Optimal cutoff ,Iron Overload ,Magnetic Resonance Spectroscopy ,Adolescent ,Urology ,Sensitivity and Specificity ,030218 nuclear medicine & medical imaging ,03 medical and health sciences ,Liver disease ,Young Adult ,0302 clinical medicine ,Liver fat ,Image Interpretation, Computer-Assisted ,medicine ,Humans ,Radiology, Nuclear Medicine and imaging ,Aged ,Retrospective Studies ,Aged, 80 and over ,Radiological and Ultrasound Technology ,business.industry ,Gastroenterology ,Middle Aged ,medicine.disease ,Magnetic Resonance Imaging ,Fatty Liver ,Liver ,Evaluation Studies as Topic ,030220 oncology & carcinogenesis ,Iron content ,Steatosis ,Siderosis ,business ,Nuclear medicine ,Multi echo - Abstract
To compare qualitative results obtained from computer-aided dual-ratio analysis on T1-weighted two-point Dixon, with T2*-corrected multi-echo Dixon and T2-corrected multi-echo single-voxel MR spectroscopy sequence (MRS) for evaluation of liver fat and iron at 3T. This retrospective, HIPAA-compliant, IRB-approved study included 479 patients with known or suspected liver disease. Two-point Dixon, multi-echo Dixon, and MR spectroscopy sequences were performed for each patient at 3T. A receiver-operating characteristic analysis was performed to compare the diagnostic performance in 80 patients using biopsy as the standard. Sensitivity, specificity, PPV, and NPV of qualitative two-point Dixon results, multi-echo Dixon (PDFF and R2*), and MRS (fat fraction and R2 water) for detection of hepatic steatosis and siderosis were assessed. Fat fractions obtained from MRS and multi-echo Dixon have equivalent accuracy for detection of hepatic steatosis (AUC, sensitivity and specificity: 0.90 vs 0.88, 0.77 vs. 0.82, and 0.90 vs. 0.82), but the optimal cutoff value is higher for MRS (6.05% vs. 3.4%). The dual-ratio Dixon discrimination technique showed high negative predictive value for detection of hepatic steatosis and siderosis (0.90 and 0.94, respectively). R2* from multi-echo Dixon and R2water from MRS have equivalent accuracy for detection of iron overload at 3T (AUC 0.89 vs. 0.88). The optimal cutoff for R2* and R2water are 60.5 s−1 and 40.85 s−1, respectively. The computer-aided dual-ratio discrimination with two-point Dixon is a useful qualitative screening tool with high negative predictive value for hepatic steatosis and iron overload. Multi-echo Dixon and MRS have similar accuracy for detection of hepatic steatosis and iron overload at 3 Tesla.
- Published
- 2019
39. Full utilization of conjugate symmetry: combining virtual conjugate coil reconstruction with partial Fourier imaging for g‐factor reduction in accelerated MRI
- Author
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Zoltán Vidnyánszky, Kawin Setsompop, Martin Blaimer, Felix A. Breuer, Stephan Kannengiesser, and Adam O. Kettinger
- Subjects
Physics ,Time Factors ,Fourier Analysis ,Computation ,Brain ,Signal-To-Noise Ratio ,Magnetic Resonance Imaging ,030218 nuclear medicine & medical imaging ,Reduction (complexity) ,03 medical and health sciences ,Noise ,Acceleration ,Direct-conversion receiver ,0302 clinical medicine ,Electromagnetic coil ,Image Processing, Computer-Assisted ,Humans ,Radiology, Nuclear Medicine and imaging ,Projection (set theory) ,Algorithm ,Algorithms ,030217 neurology & neurosurgery ,Conjugate - Abstract
Purpose In this study we propose a method to combine the parallel virtual conjugate coil (VCC) reconstruction with partial Fourier (PF) acquisition to improve reconstruction conditioning and reduce noise amplification in accelerated MRI where PF is used. Methods Accelerated measurements are reconstructed in k-space by GRAPPA, with a VCC reconstruction kernel trained and applied in the central, symmetrically sampled part of k-space, while standard reconstruction is performed on the asymmetrically sampled periphery. The two reconstructed regions are merged to form a full reconstructed dataset, followed by PF reconstruction. The method is tested in vivo using T1-weighted spin-echo and T2*-weighted gradient-echo echo planar imaging (EPI) sequences, using both in-plane and simultaneous multislice (SMS) acceleration, at 1.5T and 3T field strengths. Noise amplification is estimated with theoretical calculations and pseudo-multiple-replica computations, for different PF factors, using zero-filling, homodyne, and projection onto convex sets (POCS) PF reconstruction. Results Depending on the PF algorithm and the inherent benefit of VCC reconstruction without PF, approximately 35% to 80%, 15% to 60%, and 5% to 30% of that intrinsic SNR gain can be retained for PF factors 7/8, 6/8, and 5/8, respectively, by including the VCC signals in the reconstruction. Compared with VCC-reconstructed acquisitions of higher acceleration, without PF, but having the same net acceleration, the combined method can provide a higher SNR if the inherent benefit of VCC is low or moderate. Conclusion The proposed technique enables the partial application of VCC reconstruction to measurements with PF using either in-plane or SMS acceleration, and therefore can reduce the noise amplification of such acquisitions.
- Published
- 2019
40. Improved accuracy of apparent diffusion coefficient quantification using a fully automatic noise bias compensation method: Preliminary evaluation in prostate diffusion weighted imaging
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Xiaodong Zhong, Berthold Kiefer, Brian M. Dale, Stephan Kannengiesser, Mustafa R. Bashir, and Marcel Dominik Nickel
- Subjects
Male ,Nuclear and High Energy Physics ,Scanner ,Polynomial ,Computer science ,Biophysics ,Signal-To-Noise Ratio ,010402 general chemistry ,01 natural sciences ,Biochemistry ,Imaging phantom ,030218 nuclear medicine & medical imaging ,03 medical and health sciences ,0302 clinical medicine ,Effective diffusion coefficient ,Humans ,Prospective Studies ,Diffusion (business) ,Aged ,Protocol (science) ,Phantoms, Imaging ,Prostatic Neoplasms ,Condensed Matter Physics ,Image Enhancement ,0104 chemical sciences ,Noise ,Diffusion Magnetic Resonance Imaging ,Algorithm ,Monte Carlo Method ,Algorithms ,Diffusion MRI - Abstract
Noise in diffusion magnetic resonance imaging can introduce bias in apparent diffusion coefficient (ADC) quantification. Previous studies proposed methods that are site-specific techniques as research tools with limited availability and typically require manual intervention, not completely ready to use in the clinical environment. The purpose of this study was to develop a fully automatic computational method to correct noise bias in ADC quantification and perform a preliminary evaluation in the clinical prostate diffusion weighted imaging (DWI). Using a pseudo replica approach for the noise map calculation as well as a direct mapping and a stepwise Chebychev polynomial modelling approach for the ADC fitting, a fully automatic noise-bias-compensated ADC calculation method was proposed and implemented both on the scanner and offline. The proposed method was validated in a computer simulation and a standardized diffusion phantom with ground-truth values. Two in vivo studies were performed to evaluate the proposed method in the clinical environment. The first in vivo study performed acquisitions using a clinically routine prostate DWI protocol on 29 subjects to evaluate the consistency between simulated and empirical results. In the second in vivo study, prostate ADC values of 14 subjects were compared between data acquired with external coils only and reconstructed with the proposed method vs. acquired with external combined with endorectal coils and reconstructed with the conventional method. In statistical analyses, p 0.05 was regarded as significantly different. In the computer simulation, the proposed method showed smaller error percentage than the other methods and was significantly different (p 2.2 × 10
- Published
- 2019
41. Nichtinvasive Tumordekodierung und Phänotypisierung zerebraler Gliome unter Verwendung von multiparametrischem 18F-FET-PET-MRT und MR-Fingerprinting
- Author
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Karsten H. Wrede, M Forsting, L Umutlu, U Sure, F Meise, Johannes Haubold, M Stuschke, J Pfeufer, Martin Glas, M Gratz, A Demircioglu, Stephan Kannengiesser, K Herrmann, and Felix Nensa
- Published
- 2019
42. Pancreatic Steatosis and Fibrosis: Quantitative Assessment with Preoperative Multiparametric MR Imaging
- Author
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Jeong Min Lee, Byung Ihn Choi, Jeong Hee Yoon, Stephan Kannengiesser, Sun Whe Kim, Joon Koo Han, Mee Joo Kang, Kyung Bun Lee, and Jin-Young Jang
- Subjects
Male ,medicine.medical_specialty ,030218 nuclear medicine & medical imaging ,03 medical and health sciences ,0302 clinical medicine ,Fibrosis ,medicine ,Humans ,Radiology, Nuclear Medicine and imaging ,Intravoxel incoherent motion ,Aged ,Retrospective Studies ,Aged, 80 and over ,medicine.diagnostic_test ,business.industry ,Pancreatic Diseases ,Magnetic resonance imaging ,Middle Aged ,medicine.disease ,Magnetic Resonance Imaging ,Mr imaging ,medicine.anatomical_structure ,Adipose Tissue ,Pancreatic fistula ,030220 oncology & carcinogenesis ,Preoperative Period ,Female ,Radiology ,Steatosis ,Pancreas ,Nuclear medicine ,business ,Perfusion - Abstract
To evaluate the diagnostic performance of multiparametric pancreatic magnetic resonance (MR) imaging, including the T2*-corrected Dixon technique and intravoxel incoherent motion (IVIM) diffusion-weighted (DW) imaging, in the quantification of pancreatic steatosis and fibrosis, with histologic analysis as the reference standard, and to determine the relationship between MR parameters and postoperative pancreatic fistula.This retrospective study was approved by the institutional review board, and the informed consent requirement was waived. A total of 165 patients (93 men, 72 women; mean age, 62 years) underwent preoperative 3-T MR imaging and subsequent pancreatectomy (interval, 0-77 days). Fat fractions, IVIM DW imaging parameters (true diffusion coefficient [D], pseudodiffusion coefficient [D*], and perfusion fraction [f]), pancreas-to-muscle signal intensity ratios on unenhanced T1-weighted images, and pancreatic duct sizes were compared with the fat fractions and fibrosis degrees (F0-F3) of specimens. In 95 patients who underwent pancreatoenteric anastomosis, MR parameters were compared between groups with clinically relevant postoperative pancreatic fistula and those without. The relationship between postoperative pancreatic fistula and MR parameters was evaluated by using logistic regression analysis.Fat fractions at MR imaging showed a moderate relationship with histologic findings (r = 0.71; 95% confidence interval: 0.63, 0.78). Patients with advanced fibrosis (F2-F3) had lower D*([39.72 ± 13.64] ×10(-3)mm(2)/sec vs [32.50 ± 13.09] ×10(-3)mm(2)/sec [mean ± standard deviation], P = .004), f (29.77% ± 8.51 vs 20.82% ± 8.66, P.001), and unenhanced T1-weighted signal intensity ratio (1.43 ± 0.26 vs 1.21 ± 0.30, P.001) than did patients with F0-F1 disease. Clinically relevant fistula developed in 14 (15%) of 95 patients, and f was significantly associated with postoperative pancreatic fistula (odds ratio, 1.17; 95% confidence interval: 1.05, 1.30).Multiparametric MR imaging of the pancreas, including imaging with the T2*-corrected Dixon technique and IVIM DW imaging, may yield quantitative information regarding pancreatic steatosis and fibrosis, and f was shown to be significantly associated with postoperative pancreatic fistulas.
- Published
- 2016
43. Comparison of phase‐constrained parallel MRI approaches: Analogies and differences
- Author
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Marius Heim, Peter M. Jakob, Felix A. Breuer, Stephan Kannengiesser, Daniel Neumann, and Martin Blaimer
- Subjects
Sampling scheme ,Computer science ,Image quality ,Signal Processing, Computer-Assisted ,Iterative reconstruction ,Magnetic Resonance Imaging ,030218 nuclear medicine & medical imaging ,03 medical and health sciences ,0302 clinical medicine ,Electromagnetic coil ,Robustness (computer science) ,Image Processing, Computer-Assisted ,Radiology, Nuclear Medicine and imaging ,Conjugate symmetry ,Algorithm ,Algorithms ,030217 neurology & neurosurgery - Abstract
Purpose Phase-constrained parallel MRI approaches have the potential for significantly improving the image quality of accelerated MRI scans. The purpose of this study was to investigate the properties of two different phase-constrained parallel MRI formulations, namely the standard phase-constrained approach and the virtual conjugate coil (VCC) concept utilizing conjugate k-space symmetry. Methods Both formulations were combined with image-domain algorithms (SENSE) and a mathematical analysis was performed. Furthermore, the VCC concept was combined with k-space algorithms (GRAPPA and ESPIRiT) for image reconstruction. In vivo experiments were conducted to illustrate analogies and differences between the individual methods. Furthermore, a simple method of improving the signal-to-noise ratio by modifying the sampling scheme was implemented. Results For SENSE, the VCC concept was mathematically equivalent to the standard phase-constrained formulation and therefore yielded identical results. In conjunction with k-space algorithms, the VCC concept provided more robust results when only a limited amount of calibration data were available. Additionally, VCC-GRAPPA reconstructed images provided spatial phase information with full resolution. Conclusions Although both phase-constrained parallel MRI formulations are very similar conceptually, there exist important differences between image-domain and k-space domain reconstructions regarding the calibration robustness and the availability of high-resolution phase information. Magn Reson Med, 2015. © 2015 Wiley Periodicals, Inc.
- Published
- 2016
44. Clinical Feasibility of Gadoxetic Acid-Enhanced Isotropic High-Resolution 3-Dimensional Magnetic Resonance Cholangiography Using an Iterative Denoising Algorithm for Evaluation of the Biliary Anatomy of Living Liver Donors
- Author
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Berthold Kiefer, Jae Seok Bae, Jeong Min Lee, Kyung-Suk Suh, Su Joa Ahn, Hyo-Jin Kang, and Stephan Kannengiesser
- Subjects
Adult ,Gadolinium DTPA ,Male ,Gadoxetic acid ,Materials science ,Adolescent ,Denoising algorithm ,High resolution ,Contrast Media ,030218 nuclear medicine & medical imaging ,03 medical and health sciences ,Young Adult ,0302 clinical medicine ,Cholangiography ,Nuclear magnetic resonance ,Imaging, Three-Dimensional ,medicine ,Image Processing, Computer-Assisted ,Living Donors ,Humans ,Radiology, Nuclear Medicine and imaging ,Biliary Tract ,Retrospective Studies ,medicine.diagnostic_test ,Isotropy ,Magnetic resonance imaging ,General Medicine ,Middle Aged ,Image Enhancement ,Magnetic Resonance Imaging ,Liver Transplantation ,Biliary anatomy ,Liver donors ,Feasibility Studies ,Female ,030217 neurology & neurosurgery ,Algorithms ,medicine.drug - Abstract
The aim of this study was to evaluate the clinical feasibility of gadoxetic acid-enhanced isotropic high-resolution (IHR) 3-dimensional (3D) T1-weighted (T1W) magnetic resonance cholangiography (MRC) using an iterative denoising (ID) algorithm for evaluation of the biliary anatomy of living liver donors in comparison with conventional 3D multislice T2-weighted (T2W) MRC.In this institutional review board-approved retrospective study, a total of 75 living liver donors who underwent conventional 3D multislice T2W-MRC and IHR-3D-T1W-MRC on a 3 T scanner and subsequent right hepatectomy for liver donation were included. Isotropic high-resolution T1W-MRCs were obtained in both axial and coronal planes using the 3D VIBE Dixon sequence and an ID algorithm implemented with wavelet thresholding of 3D complex-valued data of the noise level, g-factor, and k-space filtering. Thereafter, 3 board-certified radiologists independently reviewed the examinations for visibility and sharpness of the bile ducts (BDs), as well as overall image quality on a 5-point scale. For diagnostic performance, anatomic variations of the BD, length of right hepatic duct, and the expected number of BD openings at right hepatectomy were also recorded. As the reference standard, BD variation was determined by surgeons in consensus using intraoperative real-time fluorescent cholangiography.Mean acquisition times of 3D-T2W-MRC and IHR-T1W-MRC were 367 seconds and 17 seconds (P0.001), respectively. Compared with 3D-T2W-MRCs, IHR-T1W-MRCs yielded significantly improved visibility and sharpness of all evaluated intrahepatic bile ducts (all Ps0.05), and higher overall image quality (P0.01). The IHR-T1W-MRCs also demonstrated significantly higher agreement in BD variation (87.6% vs 81.3%, P = 0.03) and expected BD openings (76.9% vs 70.2%, P = 0.006) than 3D-T2W-MRC compared with the reference standard. Interobserver agreement in estimating the length of right hepatic duct, IHR-T1W-MRC showed excellent interobserver agreement (intraclass correlation coefficient, 0.94), whereas 3D-T2W-MRC showed good interobserver agreement (intraclass correlation coefficient, 0.78).Isotropic high-resolution T1W-MRCs with ID provided significantly improved BD image quality and more accurate depiction of the BD anatomy and BD openings at right donor hemihepatetomy than 3D-T2W-MRC.
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- 2018
45. Correction to: Correlation between incidental fat deposition in the liver and pancreas in asymptomatic individuals
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Xiaodong Zhong, Li Pan, Mounes Aliyari Ghasabeh, Mohammadreza Shaghaghi, Stephan Kannengiesser, Pegah Khoshpouri, Pallavi Pandey, Ankur Pandey, and Ihab R. Kamel
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medicine.medical_specialty ,Radiological and Ultrasound Technology ,business.industry ,Urology ,Gastroenterology ,Hepatology ,Asymptomatic ,medicine.anatomical_structure ,Internal medicine ,medicine ,Radiology, Nuclear Medicine and imaging ,medicine.symptom ,Pancreas ,business ,Deposition (chemistry) - Abstract
Unfortunately the article was published with a spell error in the co-author names “Ankur Pandy and Pallavi Pandy”. The correct co-author names should be Ankur Pandey and Pallavi Pandey”.
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- 2019
46. Quantitative analysis of hepatic iron in patients suspected of coexisting iron overload and steatosis using multi-echo single-voxel magnetic resonance spectroscopy: Comparison with fat-saturated multi-echo gradient echo sequence
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Stephan Kannengiesser, Jun Shen, Huimin Lin, Shu Cheng, Haipeng Dong, Fuhua Yan, and Caixia Fu
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In vivo magnetic resonance spectroscopy ,Adult ,Male ,Liver Iron Concentration ,Cirrhosis ,Iron Overload ,Magnetic Resonance Spectroscopy ,Adolescent ,Iron ,Population ,030218 nuclear medicine & medical imaging ,03 medical and health sciences ,Young Adult ,0302 clinical medicine ,Nuclear magnetic resonance ,medicine ,Humans ,Radiology, Nuclear Medicine and imaging ,education ,Aged ,Retrospective Studies ,Aged, 80 and over ,education.field_of_study ,Receiver operating characteristic ,Chemistry ,Area under the curve ,Middle Aged ,medicine.disease ,Magnetic Resonance Imaging ,Adipose Tissue ,Liver ,ROC Curve ,030220 oncology & carcinogenesis ,Area Under Curve ,Spin echo ,Disease Progression ,Regression Analysis ,Female ,Steatosis - Abstract
Background The coexistence of hepatic iron and fat is common in patients with hyperferritinemia, which plays an interactive and aggressive role in the progression of diseases (fibrosis, cirrhosis, and hepatocellular carcinomas). Purpose To evaluate a modified high-speed T2 -corrected multi-echo, single voxel spectroscopy sequence (HISTOV) for liver iron concentration (LIC) quantification in patients with hyperferritinemia, with simultaneous fat fraction (FF) estimation. Study type Retrospective cohort study. Population Thirty-eight patients with hyperferritinemia were enrolled. Field strength/sequence HISTOV, a fat-saturated multi-echo gradient echo (GRE) sequence, and a spin echo sequence (FerriScan) were performed at 1.5T. Assessment R2 of the water signal and FF were calculated with HISTOV, and R2* values were derived from the GRE sequence, with R2 and LIC from FerriScan serving as the references. Statistical tests Linear regression, correlation analyses, receiver operating characteristic analyses, and Bland-Altman analyses were conducted. Results Abnormal hepatic iron load was detected in 32/38 patients, of whom 10/32 had coexisting steatosis. Strong correlation was found between R2* and FerriScan-LIC (R2 = 0.861), and between HISTOV-R2_ water and FerriScan-R2 (R2 = 0.889). Furthermore, HISTOV-R2_ water was not correlated with HISTOV-FF. The area under the curve (AUC) for HISTOV-R2_ water was 0.974, 0.971, and 1, corresponding to clinical FerriScan-LIC thresholds of 1.8, 3.2, and 7.0 mg/g dw, respectively. No significant difference in the AUC was found between HISTOV-R2_ water and R2* at any of the LIC thresholds, with P-values of 0.42, 0.37, and 1, respectively. HISTOV-LIC showed excellent agreement with FerriScan-LIC, with a mean bias of 0.00 ± 1.18 mg/g dw, whereas the mean bias between GRE-LIC and FerriScan-LIC was 0.53 ± 1.49 mg/g dw. Data conclusion HISTOV is useful for the quantification and grading of liver iron overload in patients with hyperferritinemia, particularly in cases with coexisting steatosis. HISTOV-LIC showed no systematic bias compared with FerriScan-LIC, making it a promising alternative for iron quantification. Level of evidence 3 Technical Efficacy Stage 2 J. Magn. Reson. Imaging 2018.
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- 2017
47. Interplatform reproducibility of liver and spleen stiffness measured with MR elastography
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Mathilde Wagner, Cecilia Besa, Bachir Taouli, Octavia Bane, Stephan Kannengiesser, T.K. Yasar, Maggie Fung, Richard L. Ehman, and James S. Babb
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Reproducibility ,Pathology ,medicine.medical_specialty ,medicine.diagnostic_test ,Intraclass correlation ,business.industry ,Coefficient of variation ,Magnetic resonance imaging ,Imaging phantom ,030218 nuclear medicine & medical imaging ,Magnetic resonance elastography ,03 medical and health sciences ,0302 clinical medicine ,medicine ,030211 gastroenterology & hepatology ,Radiology, Nuclear Medicine and imaging ,Multislice ,Elastography ,business ,Nuclear medicine - Abstract
Purpose To assess interplatform reproducibility of liver stiffness (LS) and spleen stiffness (SS) measured with magnetic resonance elastography (MRE) based on a 2D gradient echo (GRE) sequence. Materials and Methods This prospective Health Insurance Portability and Accountability Act (HIPAA)-compliant and Institutional Review Board (IRB)-approved study involved 12 subjects (five healthy volunteers and seven patients with liver disease). A multislice 2D-GRE-based MRE sequence was performed using two systems from different vendors (3.0T GE and 1.5T Siemens) on the same day. Two independent observers measured LS and SS on confidence maps. Bland–Altman analysis (with coefficient of reproducibility, CR), coefficient of variability (CV), and intraclass correlation (ICC) were used to analyze interplatform, intra- and interobserver variability. Human data were validated using a gelatin-based phantom. Results There was excellent reproducibility of phantom stiffness measurement (CV 4.4%). Mean LS values were 3.44–3.48 kPa and 3.62–3.63 kPa, and mean SS values were 7.54–7.91 kPa and 8.40–8.85 kPa at 3.0T and 1.5T for observers 1 and 2, respectively. The mean CVs between platforms were 9.2%–11.5% and 13.1%–14.4% for LS and SS, respectively, for observers 1 and 2. There was excellent interplatform reproducibility (ICC >0.88 and CR 0.99, CV 0.97, CV and CR
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- 2015
48. Feasibility of a three-step magnetic resonance imaging approach for the assessment of hepatic steatosis in an asymptomatic study population
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Holger Hetterich, Christa Meisinger, Sigrid Auweter, Birgit Ertl-Wagner, Stephan Kannengießer, Annette Peters, Fabian Bamberg, Margit Heier, Birgit Linkohr, Christian Bayerl, and Harald Kramer
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Adult ,Male ,medicine.medical_specialty ,Population ,Asymptomatic ,030218 nuclear medicine & medical imaging ,03 medical and health sciences ,0302 clinical medicine ,medicine ,Humans ,Radiology, Nuclear Medicine and imaging ,Prospective Studies ,Prospective cohort study ,education ,Aged ,Neuroradiology ,education.field_of_study ,medicine.diagnostic_test ,business.industry ,Fatty liver ,Reproducibility of Results ,Magnetic resonance imaging ,General Medicine ,Middle Aged ,medicine.disease ,Magnetic Resonance Imaging ,Fatty Liver ,Liver ,Asymptomatic Diseases ,Feasibility Studies ,Population study ,Female ,030211 gastroenterology & hepatology ,Radiology ,Steatosis ,medicine.symptom ,business - Abstract
To determine the feasibility of a multi-step magnetic resonance imaging (MRI) approach for comprehensive assessment of hepatic steatosis defined as liver fat content of ≥5 % in an asymptomatic population. The study was approved by the institutional review board and written informed consent of all participants was obtained. Participants of a population-based study cohort underwent a three-step 3-T MRI-based assessment of liver fat. A dual-echo Dixon sequence was performed to identify subjects with hepatic steatosis, followed by a multi-echo Dixon sequence with proton density fat fraction estimation. Finally, single-voxel T2-corrected multi-echo spectroscopy was performed. A total of 215 participants completed the MRI protocol (56.3 % male, average age 57.2 ± 9.4 years). The prevalence of hepatic steatosis was 55 %. Mean liver proton density fat fraction was 9.2 ± 8.5 % by multi-echo Dixon and 9.3 ± 8.6 % by multi-echo spectroscopy (p = 0.51). Dual-echo Dixon overestimated liver fat fraction by 1.4 ± 2.0 % (p
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- 2015
49. Liver fat quantification: Comparison of dual-echo and triple-echo chemical shift MRI to MR spectroscopy
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Octavia Bane, Bachir Taouli, Janakan Satkunasingham, Wesley D. Gilson, Cecilia Besa, Andre de Oliveira, Ami Shah, and Stephan Kannengiesser
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Adult ,Male ,In vivo magnetic resonance spectroscopy ,Magnetic Resonance Spectroscopy ,Concordance ,Coefficient of variation ,Liver fat ,medicine ,Humans ,Radiology, Nuclear Medicine and imaging ,Prospective Studies ,Prospective cohort study ,Aged ,medicine.diagnostic_test ,business.industry ,Fatty liver ,Reproducibility of Results ,Magnetic resonance imaging ,General Medicine ,Middle Aged ,medicine.disease ,Magnetic Resonance Imaging ,Fatty Liver ,Adipose Tissue ,Liver ,Female ,Dual echo ,business ,Nuclear medicine - Abstract
Purpose To assess the diagnostic value of MRI using dual-echo (2PD) and triple-echo (3PD) chemical shift imaging for liver fat quantification against multi-echo T2 corrected MR spectroscopy (MRS) used as the reference standard, and examine the effect of T2* imaging on accuracy of MRI for fat quantification. Materials and methods Patients who underwent 1.5 T liver MRI that incorporated 2PD, 3PD, multi-echo T2* and MRS were included in this IRB approved prospective study. Regions of interest were placed in the liver to measure fat fraction (FF) with 2PD and 3PD and compared with MRS-FF. A random subset of 25 patients with a wide range of MRS-FF was analyzed with an advanced FF calculation method, to prove concordance with the 3PD. The statistical analysis included correlation stratified according to T2*, Bland-Altman analysis, and calculation of diagnostic accuracy for detection of MRS-FF > 6.25%. Results 220 MRI studies were identified in 217 patients (mean BMI 28.0 ± 5.6). 57/217 (26.2%) patients demonstrated liver steatosis (MRS-FF > 6.25%). Bland-Altman analysis revealed strong agreement between 3PD and MRS (mean ± 1.96 SD: −0.5% ± 4.6%) and weaker agreement between 2PD and MRS (4.7% ± 16.0%). Sensitivity of 3PD for diagnosing FF> 6.25% was higher than that of 2PD. 3PD-FF showed minor discrepancies (coefficient of variation
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- 2015
50. Hepatic fat quantification using the proton density fat fraction (PDFF): utility of free-drawn-PDFF with a large coverage area
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Stephan Kannengiesser, Ji Soo Song, Kun Young Kim, and Young Min Han
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Adult ,Male ,In vivo magnetic resonance spectroscopy ,Magnetic Resonance Spectroscopy ,Adolescent ,Fat quantification ,Fats ,medicine ,Humans ,Radiology, Nuclear Medicine and imaging ,Child ,Aged ,Aged, 80 and over ,medicine.diagnostic_test ,business.industry ,Ultrasound ,Proton density fat fraction ,Magnetic resonance imaging ,General Medicine ,Middle Aged ,Reference Standards ,medicine.disease ,Magnetic Resonance Imaging ,Mr imaging ,Lobe ,Fatty Liver ,medicine.anatomical_structure ,Liver ,Female ,Steatosis ,business ,Nuclear medicine - Abstract
To evaluate the diagnostic performance of magnetic resonance imaging-estimated proton density fat fraction (MRI-PDFF) using a free-drawn region-of-interest (ROI) measurement of hepatic fat deposition compared to MR spectroscopy (MRS) as the reference standard. A total of 156 patients underwent 3T MR imaging with a multi-step adaptive fitting approach, multi-echo volume interpolated breath-hold examination (VIBE) acquisition and single-voxel high-speed T2-corrected multiple-echo 1H-MR spectroscopy (SVS). Seven ROI measurements were performed in each segment of the fat percentage maps (“segmental-PDFF”). Three ROIs were placed at the same level as the SVS (“VOI-PDFF”). Free-hand-drawn ROIs were placed at three different levels along the entire liver (“free-drawn-PDFF”) and separately along the right and left lobes (“free-drawn-PDFF-2”). A strong correlation was found between VOI-PDFF and SVS (r = 0.977). The right lobe had greater fat content than the left lobe (p
- Published
- 2015
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