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Objectives: Focal therapy with high-intensity focused ultrasound (HIFU) is an emerging option for the treatment of prostate cancer and often followed up by MRI. Image assessment of treatment failure, however, requires proper knowledge about typical procedure-related changes in prostate MRI, which is sparse, in particular for unilateral HIFU treatment and late follow up (beyond 6 months). The goal of this study was therefore to compile the type and frequency of such MRI findings in selected patients without recurrent cancer 12 months after prostate hemiablation., Methods: Data from a prospective multicenter trial on HIFU hemiablation were reviewed retrospectively. Trial patients have had a late follow-up by MRI (at around 12 months) and either MRI/transrectal ultrasound (TRUS) fusion or standard TRUS-guided biopsy. This work deliberately included patients with non-recurrent cancer in the treated prostate lobe in per-protocol biopsy leaving 30 men with initial International Society of Urological Pathology (ISUP) Grade Group of 1 or 2. Six categories of potential HIFU-related MRI features were assessed by an expert committee and then evaluated by two readers in consensus: 1. shrinkage of the treated lobe, 2. residual prostate tissue, 3. fluid-filled cavity, 4. fibrosis, 5. hematoma residuals (in the prostate or seminal vesicles) and 6. contrast enhancement of the ablated area., Results: Shrinkage of the ablated lobe was seen in 93% of the cases with an average percent volume change of -37% (range: -70% to +108%). In the contralateral lobe, the volume remained practically the same (-2% on average, p = 0.804). In the ablated lobe, the frequency of fibrosis was 97%. Residual prostate tissue was seen in 93% of the cases. The frequency for fluid-filled cavities was 97%, with the wide majority (90%) contiguous with the urethra. Hematoma residuals in the prostate and in seminal vesicles were found in 47% and 10% of the patients, respectively. Contrast enhancement was both rim-like (50%) as well as diffuse (33%) within the ablated area., Conclusion: In our case series of HIFU hemiablation in the prostate, shrinkage, residual prostate tissue, fluid-filled cavities contiguous with the urethra and fibrosis were very common late MRI findings of the ablated lobe in non-recurrent patients. Rim-like contrast enhancement or diffuse one within the ablated area were less frequent., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Purpose: Cross-sectional imaging is increasingly used to quantify adipose tissue compartments in subjects with overweight or obesity. The lack of ionizing radiation makes magnetic resonance imaging (MRI) highly preferable to computed tomography (CT) although it is generally less standardized and time-consuming. Fat areas of single or stacks of neighboring slices have previously been considered as surrogates to avoid laborious processing of whole abdominal data-but studies are inconsistent in design and results. The present work therefore analyzed a relatively large number of overweight or obese adults and involved a total of eight landmarks and two surrogates (slice and stack). The goals were to identify the most reliable estimators of abdominal subcutaneous adipose tissue (ASAT) volume for both genders and to relate the findings to the pertinent literature., Material and Methods: Anthropometric and fat-sensitive 1.5 T MRI data of 193 patients (116 female, 77 male) from different IRB-approved studies at a single clinical research institution (IFB Adiposity Diseases, University Medicine Leipzig, Germany) were analyzed retrospectively. Mean (± SD) age and BMI were 51.5 (± 12.4) years and 33.7 (± 3.9) kg/m 2 for females versus 57.6 (± 12.4) years and 32.1 (± 3.7) kg/m 2 for males. Areas of selected axial slices (10 mm thick, 0.5 mm gap) and of stacks of five slices at common landmarks - intervertebral disc spaces L1/L2 to L5/S1, anterior superior iliac spine (ASIS), femoral head (FH) and umbilicus (UM) - were considered as estimators for ASAT volume (reference). Agreement between simple areas and reference volumes was asssessed by linear regression (coefficient of determination R 2 ) as well as standard deviations of percent differences s d% between estimated and measured volumes., Results: ASAT volumes ranged from 6.61 to 21.94 L for females (mean: 13.37 L) and from 5.42 to 17.90 L (mean: 9.89 L) for males. The smallest s d% (8.4 %-10.1 %) and largest R 2 values (0.86-0.92) for single slices were observed for three candidate slice positions that were also associated with the highest ASAT volume fraction: L4/L5, L5/S1 and UM. The stack estimates for these landmarks were overall somewhat better (7.3 %-9.7 %, 0.88-0.94, respectively). The differences in s d% between genders ranged between 0.2 % and 1.1 %., Conclusion: ASAT volume in overweight or obese patients can be readily estimated with good accuracy from a single MRI slice centered at intervertebral disc space L5/S1 for both genders. Disc space L4/L5 or the umbilicus are nearly equivalent landmarks, in particular for male subjects. The extension to stack measures may yield too little improvement to justify the extra effort. Landmarks like ASIS, FH or the remaining lumbar disc spaces are considered as unreliable., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Purpose: To evaluate the imaging pattern of pancreaticobiliary lesions in patients with treated type 1AIP, to determine the incidence of disease relapse and malignancy, and to identify the risk factors., Method: The institutional review board approval was acquired. All patients gave written informed consent. From a prospective clinico-radiological database since 2012, consecutive patients with type 1 AIP who were treated and followed up (≥18 months) were identified. The presence/absence of pancreaticobiliary lesion(s) development during follow-up were assessed. The etiology was determined and the imaging pattern was compared to the initial attack. Risk factors were identified by univariate and multivariate analysis., Results: Among 103 patients with treated type 1 AIP, 44 (42.7%) developed pancreaticobiliary lesions during follow up (median time interval to initial diagnosis: 17 months, range 3-62 months), mostly after steroid discontinuation (63.6%) or during maintenance therapy (29.5%). All lesions were disease relapse, which responded to steroid treatment. At relapse, pancreatic involvement was less frequent (81.8% vs 100%, p = 0.003), and the pancreas size was smaller (p < 0.01), whereas extra-pancreatic bile duct (ExPanBD) involvement was more severe and extensive (both p < 0.01). Multivariate analysis revealed ExPanBD involvement at initial diagnosis (hazard ratio 2.437, 95% CI 1.343-7.402, p = 0.002) and serum IgG4 response ratio at the induction phase (hazard ratio 0.357, 95% CI 0.055-0.804, p = 0.011) as significant independent predictors of relapse., Conclusions: In treated type 1 AIP, although imaging pattern may differ, pancreaticobiliary lesions are usually manifestations of disease relapse. ExPanBD involvement and poor serum response suggests high risk of relapse., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Objective: To determine the prevalence of multiple solid pancreatic lesions on dynamic enhanced CT performed for suspected pancreatic diseases, and to identify CT features of non-malignancies., Methods: We investigated 8096 consecutive patients who underwent dynamic enhanced CT pancreas protocol at a tertiary center over 40 months. The final clinical /pathological diagnosis served as reference standard. The diagnostic accuracy of dynamic enhanced CT for non-malignancies was calculated. A univariate and multivariate analysis was conducted to identify features that predict non-malignancies., Results: Multiple solid pancreatic lesions were identified in 121 patients. The prevalence of non-malignancies was 19.8% (24/121). The most common non-malignancy was autoimmune pancreatitis (n = 21; 17.4%). Common lesions with malignant potential included neuroendocrine neoplasia (n = 62; 51.2%), ductal adenocarcinoma (n = 15; 12.4%), metastasis (n = 9; 7.4%), and lymphoma (n = 7; 5.8%). Dynamic enhanced CT had a sensitivity of 79.2% and a specificity of 92.8% for diagnosing non-malignancies. Elevated serum IgG4 level (p < 0.001), hypo-enhancement in arterial phase (p = 0.001), hyper-enhancement in equilibrium phase (p = 0.009) and location in both proximal and distal pancreas (p = 0.036) were predictors of non-malignancies, whereas pancreatic duct morphology and vascular invasion status were not., Conclusion: Multiple solid pancreatic lesions were rare, with a wide spectrum. Dynamic enhanced CT provides clues for identifying non-malignancies., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Objectives: To estimate the additional value of an increased flip angle of 35° in late phase Gd-EOB-DTPA-enhanced magnetic resonance cholangiography, as compared to T2w-MRCP., Methods: 40 adult patients underwent Gd-EOB-DTPA enhanced MRI of the liver including a T2-weighted 3D TSE MRCP (T2w-MRCP) as well as a late phase T1-weighted THRIVE sequences applying a flip angle of 35° (fa35). Two experienced observers evaluated the images regarding the delineation of the different biliary regions using a three-point grading system. A five-point scale was applied to determine the readers' confidence in identifying anatomical variations of the biliary tree. ROI analysis was performed to compare the signal-to-noise (SNR) and contrast-to-noise (CNR) ratios., Results: The quality for visualizing the biliary tree differed between T2w-MRCP and fa35 (p=<0.001). Late phase EOB-MRC was rated as good for delineating the entire biliary system, whereas T2w-MRCP received an overall poor rating. Especially the depiction of the intrahepatic bile ducts was estimated as problematic in T2w-MRCP. T2w-MRCP and fa35 revealed a discordant assessment of anatomical variations in 12.5% of the cases, comprising a generally higher confidence level for fa35 (4.0 ± 1.1 vs. 2.2 ± 1.2, p=<0.001). SNR proofed to be significantly higher in fa35 (p=<0.001), whereas T2w-MRCP revealed a significantly higher CNR (<0.001)., Conclusions: Gd-EOB-DTPA enhanced magnetic resonance cholangiography acquired with a flip angle of 35° revealed a better diagnostic performance compared to T2w-MRCP and might be a valuable adjunct in assessing functional bile duct abnormalities., (Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.)

Purpose: To retrospectively analyze the degree of artefacts in CT and MRI scans caused by coils and vascular plugs used for portal vein embolization (PVE)., Materials and Methods: All patients who underwent PVE between July 2011 and December 2012 and received either plug or coil embolization additional to particle embolization were retrospectively analyzed. Artefacts causes by embolization materials were measured in CT and MRI scans following PVE., Results: The sum of the artefact diameters caused from coils was significantly higher in CT (188.3 ± 26.1 mm) than in MRI T1 (50.5 ± 6.5 mm) or T2 imaging (39.5 ± 9.7 mm) (P<0.05). In MRI, the diameter in T1 and T2 sequences did not differ significantly (P=0.977). The sum of the artefact diameters from vascular plugs in MRI T1 sequences (62.5 ± 8.7 mm) was significantly higher than in CT (46.6 ± 4.8 mm; P<0.05) and MRI T2 sequences (52.8 ± 3.8 mm; P<0.05)., Conclusion: PVE with particles and vascular plug causes significantly fewer artefacts than PVE with particles and coils on CT scans following embolization, which can be important in the event of vascular complications or in follow-up scans, should the patient become unresectable., (Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.)

Objective: To compare different three-dimensional volumetric algorithms (3D-algorithms) and RECIST for size measurement and response assessment in liver metastases from colorectal and pancreatic cancer., Methods: The volumes of a total of 102 liver metastases in 45 patients (pancreatic cancer, n=22; colon cancer, n=23) were estimated using three volumetric methods (seeded region growing method, slice-based segmentation, threshold-based segmentation) and the RECIST 1.1 method with volume calculation based on the largest axial diameter. Each measurement was performed three times by one observer. All four methods were applied to follow-up on 55 liver metastases in 29 patients undergoing systemic treatment (median follow-up, 3.5 months; range, 1-10 months). Analysis of variance (ANOVA) with post hoc tests was performed to analyze intraobserver variability and intermethod differences., Results: ANOVA showed significant higher volumes calculated according to the RECIST guideline compared to the other measurement methods (p<0.001) with relative differences ranging from 0.4% to 41.1%. Intraobserver variability was significantly higher (p<0.001) for RECIST and threshold based segmentation (3.6-32.8%) compared with slice segmentation (0.4-13.7%) and seeded region growing method (0.6-10.8%). In the follow-up study, the 3D-algorithms and the assessment following RECIST 1.1 showed a discordant classification of treatment response in 10-21% of the patients., Conclusions: This study supports the use of volumetric measurement methods due to significant higher intraobserver reproducibility compared to RECIST. Substantial discrepancies in tumor response classification between RECIST and volumetric methods depending on applied thresholds confirm the requirement of a consensus concerning volumetric criteria for response assessment., (Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.)

Purpose: There are different therapeutic options in non-functional well to moderately differentiated (G1 and G2) pancreatic neuroendocrine tumors (pNET) with unresectable hepatic metastases including systemic chemotherapy and novel molecular targeted therapies. Treatment with somatostatin analogs (SSA) as antiproliferative agents is optional. At initial diagnosis watchful waiting until tumor progression is a well-established approach. Goal of this study was to evaluate imaging features as potential prognostic factors predicting early tumor progression in order to select patients that might benefit from an earlier initiation of medical treatment., Patients and Methods: In 44 patients we correlated tumor grade, chromogranin A (CgA) levels, treatment with SSA and imaging features of hepatic metastases on contrast-enhanced multiphase CT and MR imaging with time to tumor progression (TTP) according to RECIST 1.0., Results: In the total patient cohort none of the tested imaging features was found to be a statistically significant prognostic factor for TTP. Since treatment with SSA was associated with an increased TTP we also analyzed a subgroup of 30 patients not treated with SSA. In this subgroup of patients hypoenhancement of hepatic metastases during early contrast phases was found to be a negative prognostic factor for early tumor progression within 12 months (p=0.039). The other evaluated parameters including hepatic tumor load, number of metastases, and presence of regressive morphological changes did not reveal significant results., Conclusion: Hypovascularization of liver metastases from G1 and G2 pNET reflected by hypoenhancement during the early contrast phases seems to be associated with early tumor progression. In patients with hypoenhancing metastases repeated biopsy for reassessment of grading of these metastases, and early initiation of therapy should be considered., (Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.)

Purpose: To evaluate technical feasibility and clinical outcome of computed tomography-guided high-dose-rate-brachytherapy (CT-HDRBT) ablation of metastases adjacent to the liver hilum., Materials and Methods: Between November 2007 and May 2012, 32 consecutive patients with 34 metastases adjacent to the liver hilum (common bile duct or hepatic bifurcation ≤5 mm distance) were treated with CT-HDRBT. Treatment was performed by CT-guided applicator placement and high-dose-rate brachytherapy with an iridium-192 source. MRI follow-up was performed 6 weeks and every 3 months post intervention. The primary endpoint was local tumor control (LTC); secondary endpoints included time to progression (TTP) and overall survival (OS)., Results: Patients were available for MRI evaluation for a mean follow-up time of 18.75 months (range: 3-56 months). Mean tumor diameter was 4.3 cm (range: 1.3-10.7 cm). One major complication was observed. Four (11.8%) local recurrences were observed after a local tumor control of 5, 8, 9 and 10 months, respectively. Twenty-two patients (68.75%) experienced a systemic tumor progression during the follow up period. Mean TTP was 12.9 months (range: 2-56 months). Nine patients died during the follow-up period. Median OS was 20.24 months., Conclusion: Minimally invasive CT-HDRBT is a safe and effective option also for unresectable liver metastases adjacent to the liver hilum that would have been untreatable by thermal ablation., (Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.)

Objectives: To assess the improvement of bile duct visualization in Gd-EOB-DTPA enhanced MR-cholangiography (EOB-MRC) by using an increased flip angle., Methods: 35 patients underwent Gd-EOB-DTPA enhanced MRI of the liver including T2-weighted MRCP and hepatobiliary phase EOB-MRC using a flip angle of 10° (FA10) and of 35° (FA35), respectively. Images were evaluated regarding the delineation of biliary ducts, the order of branching and anatomic visualization of the biliary tree. ROI analysis was performed to estimate the signal-to-noise (SNR) and contrast-to-noise (CNR) ratios., Results: Applying the FA35 resulted in a significantly better SNR and CNR as compared to FA10. The overall image quality was rated as good for both, FA10 and FA35. The overall rating for regional delineation of the biliary system was rated significantly better for FA35 than for FA10 (p=0.02). Classification of bile duct anatomy variations, however, was equivalent in both techniques., Conclusions: Increasing the flip angle of a T1-weighted 3D-sequence from 10° to 35° during the hepatobiliary phase of Gd-EOB enhanced MRI visually and quantitatively improved the visualization of the biliary ducts., (Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.)

Purpose: The purpose of this study was to retrospectively evaluate whether computed tomography (CT) findings have prognostic value for the prediction of mortality and severity of the clinical course in patients presenting with early stage of acute respiratory distress syndrome (ARDS) due to swine-origin influenza A (S-OIV)., Materials and Methods: Chest CT (16-/64-row multidetector CT) of 23 patients (of whom 9 patients died) were retrospectively reviewed by three independent blinded observers. The CT findings were graded on a 3-point scale (1: normal attenuation, 2: ground-glass attenuation, 3: consolidation). The extent of each abnormality was determined by visually estimating the percentage (to the nearest 10%) of the affected lung parenchyma in each zone and multiplied by the CT-score described above., Results: All patients presented with a mixture of bilateral patchy consolidations and ground glass opacities. Spearman rank correlation in evaluation of the presence and extent of lung abnormalities by the three different observers was good (correlation coefficient, 0.876-0.922; p < 0.001). The overall CT-score in survivors (mean, 96.0 (± 26.2); range, 53-158) was significantly lower than that in non-survivors (mean, 116.2 (± 14.0); range, 101-139). ROC analysis revealed an area under curve of 0.79 (p = 0.021) for the CT score with an optimal cutoff value of a CT-score of 100 for prediction of survival, with a sensitivity of 100% and a specificity of 64% (accuracy, 78%). For this optimal cutoff, Kaplan-Meier estimator showed a significant difference for the survival ratio (p = 0.011)., Conclusion: In patients with severe ARDS due to S-OIV-infection, the CT-score has a prognostic value in the prediction of mortality., (Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.)