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Purpose: Adjuvant radiochemotherapy (RCHT) improves survival of patients with locally advanced gastric cancer. Conventional three-dimensional conformal radiotherapy (3D-CRT) results in ablative doses to a significant amount of the left kidney, while image-guided intensity-modulated radiotherapy (IG-IMRT) provides excellent target coverage with improved kidney sparing. Few long-term results on IMRT for gastric cancer, however, have been published. Functional magnetic resonance imaging (fMRI) at 3.0 T including blood oxygenation-level dependent (BOLD) imaging, diffusion-weighted imaging (DWI) and, for the first time, (23)Na imaging was used to evaluate renal status after radiotherapy with 3D-CRT or IG-IMRT.Patients and Methods: Four disease-free patients (2 after 3D-CRT and 2 after IMRT; FU for all patients > 5 years) were included in this feasibility study. Morphological sequences, axial DWI images, 2D-gradient echo (GRE)-BOLD images, and (23)Na images were acquired. Mean values/standard deviations for ((23)Na), the apparent diffusion coefficient (ADC), and R2* values were calculated for the upper/middle/lower parts of both kidneys. Corticomedullary (23)Na-concentration gradients were determined.Results: Surprisingly, IG-IMRT patients showed no morphological alterations and no statistically significant differences of ADC and R2* values in all renal parts. Values for mean corticomedullary (23)Na-concentration matched those for healthy volunteers. Results were similar in 3D-CRT patients, except for the cranial part of the left kidney. This was atrophic and presented significantly reduced functional parameters (p = 0.001-p = 0.033). Reduced ADC values indicated reduced cell density and reduced extracellular space. Cortical and medullary R2* values of the left cranial kidney in the 3D-CRT group were higher, indicating more deoxygenated hemoglobin due to reduced blood flow/oxygenation. ((23)Na) of the renal cranial parts in the 3D-CRT group was significantly reduced, while the expected corticomedullary (23)Na-concentration gradient was partially conserved.Conclusions: Functional MRI can assess postradiotherapeutic renal changes. As expected, marked morphological/functional effects were observed in high-dose areas (3D-CRT), while, unexpectedly, no alteration in kidney function was observed in IG-IMRT patients, supporting the hypothesis that reducing total/fractional dose to the renal parenchyma by IMRT is clinically beneficial. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the diagnostic efficacy of macrocyclic paramagnetic gadolinium (Gd) chelates gadoterate (0.5 mmol/mL) and gadobutrol (1.0 mmol/mL) for the diagnosis of clinically significant abdominal/lower limb arterial diseases at 3.0T.Materials and Methods: This study was conducted as a prospective, single-center, randomized, double-blind, intraindividual study comparing single dose (0.1 mmol/kg) gadoterate enhanced-MRA (magnetic resonance angiography) with gadobutrol enhanced-MRA at 3.0T for their diagnostic potential in patients with peripheral artery disease. A total of 20 patients were included in this trial.Results: Fourteen patients were eligible for the final efficacy analysis. The overall image quality (excellent/more than adequate) was better rated with gadoterate than with gadobutrol (100% vs. 78.6%, 100% vs. 92.9%, 100% vs. 85.7%, 100% vs. 85.7% for readers 1, 2, 3, 4, respectively). Diagnostic confidence was rated high/excellent in 100% (readers 1, 2, and 3) and 92.9% (reader 4) with gadoterate compared to 92.9% (readers 1 and 2) and 85.7% (readers 3 and 4) with gadobutrol. Higher signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) values were obtained for gadobutrol compared to gadoterate (26.1/23.4, P = 0.01, and 22.7/20.2, P = 0.01). For the secondary criteria, no differences between groups were reported. No adverse events were reported.Conclusion: Gadobutrol yielded significantly higher SNR/CNR while gadoterate was better rated in terms of overall image quality and diagnostic confidence (P > 0.05). [ABSTRACT FROM AUTHOR]

Objectives: To evaluate MRI using T1 and T2* mapping sequences in patients with suspected hepatic iron overload (HIO).Methods: Twenty-five consecutive patients with clinically suspected HIO were retrospectively studied. All underwent MRI and liver biopsy. For the quantification of liver T2* values we used a fat-saturated multi-echo gradient echo sequence with 12 echoes (TR = 200 ms, TE = 0.99 ms +  n × 1.41 ms, flip angle 20°). T1 values were obtained using a fast T1 mapping sequence based on an inversion recovery snapshot FLASH sequence. Parameter maps were analysed using regions of interest.Results: ROC analysis calculated cut-off points at 10.07 ms and 15.47 ms for T2* in the determination of HIO with accuracy 88 %/88 %, sensitivity 84 %/89.5 % and specificity 100 %/83 %. MRI correctly classified 20 patients (80 %). All patients with HIO only had decreased T1 and T2* relaxation times. There was a significant difference in T1 between patients with HIO only and patients with HIO and steatohepatitis (P = 0.018).Conclusions: MRI-based T2* relaxation diagnoses HIO very accurately, even at low iron concentrations. Important additional information may be obtained by the combination of T1 and T2* mapping. It is a rapid, non-invasive, accurate and reproducible technique for validating the evidence of even low hepatic iron concentrations.Key Points: • Hepatic iron overload causes fibrosis, cirrhosis and increases hepatocellular carcinoma risk. • MRI detects iron because of the field heterogeneity generated by haemosiderin. • T2* relaxation is very accurate in diagnosing hepatic iron overload. • Additional information may be obtained by T1 and T2* mapping. [ABSTRACT FROM AUTHOR]

Ultrasound is of great importance in the diagnosis of acute and chronic diseases in urology, such as kidney colic, testicular torsion, low-grade kidney trauma or for follow-up of vesicoureteral reflux, evaluation of infertility, measurement of residual urinary volume and the detection of cancer. An ultrasound examination is time and cost-effective without exposure to ionizing radiation and is routinely performed by practitioners as well as in the clinical daily routine. With technical innovations, such as contrast-enhanced ultrasound or real time elastography, it would for instance be possible to extend the application field of ultrasound. However, in some fields of investigation ultrasound still lacks accuracy and despite its many advantages the validity of ultrasound findings sometimes has to be verified with computed tomography (CT) or magnetic resonance imaging (MRI). [ABSTRACT FROM AUTHOR]

Objectives: To compare 3D non-enhanced ECG-gated inflow-dependent MRA (NE-MRA) vs. continuous table movement (CTM) MR-angiography and time-resolved TWIST-MRA in the calf station at 3.0 T in a clinical patient collective.Methods: 36 patients (27 male/9 female, 66.1 ± 14.4 years) with PAOD (stage II-IV) underwent during a single MRI: NE-MRA, contrast-enhanced CTM-MRA and TWIST-MRA with a single dose of a gadolinium-based contrast agent. The image quality (IQ) and the degree of stenoses were rated on a four-point scale. Positive (PPV) and negative predictive values (NPV), sensitivity (SS) and specificity (SP) for stenoses detection were calculated for NE-MRA vs. CTM-MRA and vs. TWIST-MRA. Values were obtained for overall graduation of wall changes and for severe stenoses (>70%).Results: With NE-MRA 122/288 segments were not assessable. Compared with CTM-MRA and TWIST-MRA the IQ was significantly inferior (p < 0.0001 to p = 0.0426). CTM-MRA/TWIST-MRA detected stenoses in 44.9%/46.1% of the segments, NE-MRA in 53.5%. SS/NPV of the NE-MRA ranged from 97.8 to 100%. The SP and PPV ranged from 72.7 to 85.5% and 66.7 to 78.2%.Conclusion: Contrast-enhanced MRA techniques are superior to NE-MRA regarding IQ and correct identification of stenoses. If technically successful, NE-MRA is characterised by high NPV and overestimation of the degree of stenoses. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the effect of the number of readers on the statistical results in peripheral MRA.Materials and Methods: 40 patients with peripheral arterial occlusive disease were included as a sample dataset in this study, randomly separated into two matched groups with n = 20 patients (group 1--gadobutrol, group 2--gadoterate meglumine) who underwent a continuous table movement MRA of the peripheral vessels at 3 T. Image quality (IQ) of 17 vessel segments was evaluated by 5 independent readers. The effect of the number of readers on significance and statistical power was statistically analyzed.Results: Image quality in group 1 (gadobutrol) ranks significantly higher compared to group 2 (gadoterade meglumine) with a diagnostic IQ in 97% vs. 78% (p < 0.0001). For the diagnostic/non-diagnostic IQ assessment significance was reached with one reader 1/5 times (20%), with two readers in 4/10 (40%), with three readers in 6/10 (60%), with four readers in 4/5 (80%), with five readers in 1/1 (100%). Power considerations showed considerable gain when increasing the number of readers.Conclusion: Increasing the number of readers in a diagnostic MRA-study can be used to achieve a higher power or to decrease the number of subjects included with maintained statistical validity. [ABSTRACT FROM AUTHOR]

Objective: To compare the image quality of contrast-enhanced magnetic resonance angiography (CE-MRA) of the supra-aortic vessels at 0.05 mmol/kg bw and 0.1 mmol/kg bw, between gadobutrol, Gd-DTPA and Gd-BOPTA quantitatively and qualitatively a total of eight pigs were evaluated intraindividually at 1.5 T.Methods: Each pig was examined using 0.1 mmol/kg gadobutrol, Gd-DTPA and Gd-BOPTA on day one and 0.05 mmol/kg on day two. MRA datasets for the carotid artery and the infraorbital artery were qualitatively assessed regarding overall image quality on an ordinal four-point scale (4-excellent, 1-non-diagnostic). The signal-to noise-ratio (SNR) was measured.Results: The qualitative assessment of the carotid artery showed a higher median image quality for the 0.1 mmol dose than for the 0.05 mmol dose for all three compounds. No difference was found for the infraorbital artery. Mean SNR of Gd-BOPTA, Gd-DTPA, gadobutrol at 0.05 mmol/kg were 36.0 ± 13.4/37.9 ± 16.3/43.7 ± 0.4 and at 0.1 mmol/kg they were 50.1 ± 12.4/46.6 ± 6.5 / 54.6 ± 10.2. Gd-BOPTA 0.05 revealed a significantly lower SNR than all other agents at normal dose.Conclusions: Full-dose gadolinium MRA results in higher image quality and significantly higher SNR compared with the half dose. Gadobutrol and Gd-BOPTA have similar enhancement properties at full dose but at half dose, gadobutrol appears superior. [ABSTRACT FROM AUTHOR]

Objectives: To evaluate a whole body (WB) continuous-table-movement (CTM) MR protocol for the assessment of multiple myeloma (MM) in comparison to a step-by-step WB protocol.Methods: Eighteen patients with MM were examined at 1.5T using a WB CTM protocol (axial T2-w fs BLADE, T1-w GRE sequence) and a step-by-step WB protocol including coronal/sagittal T1-w SE and STIR sequences as reference. Protocol time was assessed. Image quality, artefacts, liver/spleen assessability, and the ability to depict bone marrow lesions less than or greater than 1 cm as well as diffuse infiltration and soft tissue lesions were rated. Potential changes in the Durie and Salmon Plus stage and the detectability of complications were assessed.Results: Mean protocol time was 6:38 min (CTM) compared to 24:32 min (standard). Image quality was comparable. Artefacts were more prominent using the CTM protocol (P = 0.0039). Organ assessability was better using the CTM protocol (P < 0.001). Depiction of bone marrow and soft tissue lesions was identical without a staging shift. Vertebral fractures were not detected using the CTM protocol.Conclusions: The new protocol allows a higher patient throughput and facilitates the depiction of extramedullary lesions. However, as long as vertebral fractures are not detectable, the protocol cannot be safely used for clinical routine without the acquisition of an additional sagittal sequence. [ABSTRACT FROM AUTHOR]

The purpose of this study was to investigate the influence of different injection rates on the maximum signal intensity and the arterio-venous transit time of dynamic gadofosveset-enhanced first pass MR angiography (MRA). Twenty-one healthy male volunteers were examined with a time-resolved echo-shared MRA at 1.5 T. The volunteers were assigned into three groups using injection rates of either 1, 2 or 4 ml/s. The maximal signal enhancement and peak signal-to-noise ratio in the pulmonary trunk, the aortic arch, the abdominal aorta as well as both kidneys and lung parenchyma were analyzed. The arterio-venous transit time was determined. The time between maximal enhancement of the pulmonary trunk and the aortic arch was higher with the slow injection rate of 1 ml/s, while there were no differences in the time between maximal enhancement of the aortic arch and the abdominal aorta above or below the origin of the renal veins with all three injection rates. With the slow injection protocol of 1 ml/s a longer purely arterial phase of 10.5 s was achieved compared to 7.7 s with higher injection rates (p = 0.045). The time between maximal aortic signal intensity and maximal renal enhancement was equal for all injection protocols. [ABSTRACT FROM AUTHOR]

The purpose was to evaluate the image quality of high-spatial resolution MRA of the renal arteries at 1.5 T after contrast-agent injection of 0.2 mmol/kg body weight (BW) in an interindividual comparison to 3.0 T after contrast-agent injection of 0.1 mmol/kg BW contrast agent (CA). After IRB approval and informed consent, 40 consecutive patients (25 men, 15 women; mean age 53.9 years) underwent MRA of the renal arteries either at a 1.5-T MR system with 0.2 mmol/kg BW gadobutrol or at a 3.0-T MR scanner with 0.1 mmol/kg BW gadobenate dimeglumine used as CA in a randomized order. A constant volume of 15 ml of these contrast agents was applied. The spatial resolution of the MRA sequences was 1.0 x 0.8 x 1.0 mm(3) at 1.5 T and 0.9 x 0.8 x 0.9 mm(3) at 3.0 T, which was achieved by using parallel imaging acceleration factors of 2 at 1.5 T and 3 at 3.0 T, respectively. Two radiologists blinded to the administered CA and the field strength assessed the image quality and the venous overlay for the aorta, the proximal and distal renal arteries independently on a four-point Likert-type scale. Phantom measurements were performed for a standardized comparison of SNR at 1.5 T and 3.0 T. There was no significant difference (p > 0.05) between the image quality at 3.0 T with 0.1 mmol/kg BW gadobenate dimeglumine compared to the exams at 1.5 T with 0.2 mmol/kg BW gadobutrol. The median scores were between 3 and 4 (good to excellent vessel visualization) for the aorta (3 at 1.5 T/4 at 3.0 T for reader 1 and 2). For the proximal renal arteries, median scores were 3 for the left and right renal artery at 1.5 T for both readers. At 3.0 T, median scores were 3 (left proximal renal artery) and 4 (right proximal renal artery) for reader 1 and 3 (left/right) for reader 2 at 3.0 T. For the distal renal arteries, median scores were between 2 and 3 at both field strengths (moderate and good) for both readers. The kappa values for both field strengths were comparable and ranged between 0.571 (moderate) for the distal renal arteries and 0.905 (almost perfect) for the proximal renal arteries. In the phantom measurements, a 40% higher SNR was found for the measurements at 3 T with gadobenate dimeglumine. High-spatial resolution renal MRA at 3.0 T with 0.1 mmol/kg BW gadobenate dimeglumine yields at least equal image quality compared with renal MRA at 1.5 T with 0.2 mmol/kg BW gadobutrol. [ABSTRACT FROM AUTHOR]

A case of a patient in his early 60s with a portal vein stenosis after liver transplantation (LTx) detected by sonography in B-flow mode is reported. Two weeks after LTx, the patient developed ascites and severe alteration of liver function tests. Color Doppler (CD) demonstrated a stenosis in the portal vein with a maximum flow of 340 cm/sec. Due to aliasing, correct assessment of stenosis diameter was not possible by means of CD. However, by using the B-flow imaging technique, slow and fast velocities in the pre-, intra-, and poststenotic segment could be detected without aliasing or overwriting. In addition, a second stenosis in the portal vein was identified. For the follow-up outcome of patients, it is essential to detect and treat this complication. After surgical intervention, graft function recovered and postoperative flow measurements showed a normal portal vein flow of 70 cm/sec in the poststenotic segment. [ABSTRACT FROM AUTHOR]

Renal magnetic resonance (MR) imaging has undergone major improvements in the past several years. This review focuses on the technical basics and clinical applications of MR angiography (MRA) with the goal of enabling readers to acquire high-resolution, high quality renal artery MRA. The current role of contrast agents and their safe use in patients with renal impairment is discussed. In addition, an overview of promising techniques on the horizon for renal MR is provided. The clinical value and specific applications of renal MR are critically discussed. [ABSTRACT FROM AUTHOR]

Abstract: Purpose: To assess the interobserver agreement in a semi-automated quantification approach of MR-renal perfusion and filtration parameters with a two-compartment model analysis. Materials and methods: Twelve consecutive patients underwent renal perfusion measurements after intravenous injection of 7ml Gd-BOPTA at 4ml/s at 3.0T. Two independent observers placed two regions of interest (ROI) manually on the axial slice, one in the abdominal aorta to determine the arterial input function (AIF), and one at the tissue–air interface for retrospective triggering. The data were fitted on a pixel-by-pixel basis to the two-compartment model, producing maps of the perfusion parameters F P (plasma flow), T P (plasma mean transit time) and of the tubular filtration parameters F T (tubular flow) and T T (tubular mean transit time). A cortical ROI was segmented by selecting those pixels with plasma volume V P >10ml/100ml, and the model fit was repeated on a ROI basis to produce the cortical averages. Results: The average values (observer 1/observer 2) were F P (226.2/187.3ml/100ml/min), T P (9.0/9.1s), F T (23.5/20.8ml/100ml/min), T T (142.1/140.0s). The correlation coefficients between both observers were 0.90 (F P), 0.80 (T P), 0.80 (F T), 0.78 (T T). Correlations of all values were significant (p <0.05). A paired t-test yielded significant differences for F P (p =0.004). Discussion/conclusion: The data demonstrate a significant systematic difference for the parameter F P, while T P seems to be most stable. Further decrease of the residual variability of all parameters seems desirable to improve the robustness of the method for clinical routine. [Copyright &y& Elsevier]

Prostate cancer detection with magnetic resonance imaging is based on a standardized MRI-protocol according to the PI-RADS guidelines including morphologic imaging, diffusion weighted imaging, and perfusion. To facilitate data acquisition and analysis the contrast-enhanced perfusion is often omitted resulting in a biparametric prostate MRI protocol. The intention of this review is to analyze the current value of biparametric prostate MRI in combination with methods of machine-learning and deep learning in the detection, grading, and characterization of prostate cancer; if available a direct comparison with human radiologist performance was performed. PubMed was systematically queried and 29 appropriate studies were identified and retrieved. The data show that detection of clinically significant prostate cancer and differentiation of prostate cancer from non-cancerous tissue using machine-learning and deep learning is feasible with promising results. Some techniques of machine-learning and deep-learning currently seem to be equally good as human radiologists in terms of classification of single lesion according to the PIRADS score.

Clinical/methodical Issue: Radiological emergencies or incidental findings that require rapid treatment are part of the daily routine of radiological units in clinics-but also in outpatient radiology. What is special about the care of these patients in the outpatient radiological area?, Standard Radiological Methods: An acute or incidental diagnosis of an emergency situation generally occurs with CT or MRI. Outpatient radiology serves as a gatekeeper by preselecting critical cases and then, in close cooperation with all those involved, providing optimal therapy., Methodological Innovations: Use of CT and MRI to assess the emergency situation allows optimal therapy for the patient to be initiated. In outpatient radiology, close cooperation in the team with the patient and the referring physicians means achieving an optimal result, which can be a great opportunity., Achievements: Close personal collaboration in the team with the referring physician and the patient is a decisive strength of outpatient radiology and can guarantee optimum care for the patient, especially in the case of acute emergencies or incidental findings which turn out to be clinical-radiological emergencies. The largest challenge in outpatient radiology is to select the critical cases of the many noncritical cases in the face of growing time and cost pressure in a time-economic manner., Practical Recommendations: Outpatient radiology should be aware of the chance for close cooperation and communication with referring physician and patient, especially in emergency situations-for the well-being of the patient, but also to increase the acceptance and significance of the field of radiology.

Systemic mastocytosis (SM) is broadly subcategorized according to mast cell (MC) burden and organ involvement into indolent (ISM), smoldering (SSM), and advanced SM (AdvSM). However, the pattern and extent of bone involvement remains controversial. In this institutional review board (IRB)-approved study, 115 patients with different forms of SM (ISM (n = 37, 32%), SSM (n = 9, 8%), and AdvSM (n = 69, 60%)) underwent a whole-body magnetic resonance imaging including sagittal and coronal T1 and turbo inversion recovery magnitude (TIRM) sequences of the spine. The evaluation included the pattern and extent of pathologic bone marrow (BM) signals in the spine and extremities, osteolytic lesions, and vertebral fractures. A pathologic BM pattern was observed in 4/37 (11%), 8/9 (89%), and 66/69 (96%); affection of the appendicular skeleton in 3/37 (8%), 8/9 (89%), and 67/69 (97%); and vertebral fractures in 7/37 (19%), 0/9, and 13/69 (19%) patients with ISM, SSM, and AdvSM, respectively. In AdvSM, pathologic BM pattern included activated (62%), diffuse sclerotic (25%), and small-spotted BM (9%), respectively. Only activated/sclerotic BM was associated with significantly higher MC burden, organ damage, and inferior median survival (2.9 years, p = 0.04). Vertebral fractures resembled classical multi-segmental osteoporotic fractures in ISM but not in AdvSM in which they were only found in activated/sclerotic BM. Only one patient with AdvSM had a focal osteolytic lesion in the femur. Activated/sclerotic BM changes of the spine and affection of the appendicular skeleton are indicative for SSM or AdvSM. Osteolytic lesions, which are very rare, and osteoporotic fractures are ineligible for the diagnosis of AdvSM.

Objective: The aim of this study was to assess the potential risk of gadobutrol-enhanced magnetic resonance imaging (MRI) in patients with moderate to severe renal impairment for the development of nephrogenic systemic fibrosis (NSF)., Materials and Methods: We performed a prospective, international, multicenter, open-label study in 55 centers. Patients with moderate to severe renal impairment scheduled for any gadobutrol-enhanced MRI were included. All patients received a single intravenous bolus injection of gadobutrol at a dose of 0.1 mmol/kg body weight. The primary target variable was the number of patients who develop NSF within a 2-year follow-up period., Results: A total of 908 patients were enrolled, including 586 with moderate and 284 with severe renal impairment who are at highest risk for developing NSF. The mean time since renal disease diagnosis was 1.83 and 5.49 years in the moderate and severe renal impairment cohort, respectively. Overall, 184 patients (20.3%) underwent further contrast-enhanced MRI with other gadolinium-based contrast agents within the 2-year follow-up. No patient developed symptoms conclusive of NSF., Conclusions: No safety concerns with gadobutrol in patients with moderate to severe renal impairment were identified. There were no NSF cases., Competing Interests: and source of funding: M.A., H.D., G.B., M.G., R.W., W.K., and F.D.C. have no conflicts of interest to disclose. H.M., B.E.-W., and R.H. received honoraria and/or research grants from Bayer. M.R., T.B., and J.E. are Bayer employees. The study was funded by Bayer Pharma AG.

Objectives: Ferumoxytol, an intravenous iron supplement, can be used in off-label mode as a contrast agent in magnetic resonance imaging. The aim of this study was to assess whether ferumoxytol can be used as a marker of inflammation in animal models of acute and chronic inflammatory kidney diseases., Material and Methods: The institutional animal care committee approved this study. A total of 18 rats were examined: 6 healthy Sprague Dawley rats as a control group; 6 rats with polycystic kidney disease (PKD) as a model for chronic inflammatory disease; Thy-1, an antibody triggering glomerulonephritis, was injected in 6 rats as a model for acute inflammation. Each rat was examined directly before and 24 hours after intravenous administration of ferumoxytol at a dose of 30 mg Fe/kg body weight. T2* times of renal tissue were approximated using a multiecho sequence. Changes in relative T2* times and T2 signal intensity after ferumoxytol injection were calculated., Results: Statistically significant differences between the 3 groups were found: the T2* times of both, Thy-1 and PKD rats were statistically significant different compared with the control group (T2* time ratio after/before: Thy-1, 0.21; PKD, 0.19, control, 0.28; P = 0.002). The highest T2 signal loss in the renal cortex was observed in the Thy-1 rats (T2 signal intensity ratio after/before: Thy-1, 0.49; PKD, 0.79; control, 0.78; P = 0.0005)., Conclusions: Ferumoxytol-enhanced magnetic resonance imaging allows detection and differentiation of acute and chronic inflammatory kidney disease based on different patterns of parenchymal ferumoxytol depositions. Ferumoxytol thus might help to differentiate between different types of inflammation in various kidney diseases.

Purpose: The purpose of this study was to determine the value of dynamic pelvic floor MRI relative to standard clinical examinations in treatment decisions made by an interdisciplinary team of specialists in a center for pelvic floor dysfunction., Methods: 60 women were referred for dynamic pelvic floor MRI by an interdisciplinary team of specialists of a pelvic floor center. All patients were clinically examined by an urologist, gynecologist, a proctological, and colorectal surgeon. The specialists assessed individually and in consensus, whether (1) MRI provides important additional information not evident by physical examination and in consensus whether (2) MRI influenced the treatment strategy and/or (3) changed management or the surgical procedure., Results: MRI was rated essential to the treatment decision in 22/50 cases, leading to a treatment change in 13 cases. In 12 cases, an enterocele was diagnosed by MRI but was not detected on physical exam. In 4 cases an enterocele and in 2 cases a rectocele were suspected clinically but not confirmed by MRI. In 4 cases, MRI proved critical in assessment of rectocele size. Vaginal intussusception detected on MRI was likewise missed by gynecologic exam in 1 case., Conclusion: MRI allows diagnosis of clinically occult enteroceles, by comprehensively evaluating the interaction between the pelvic floor and viscera. In nearly half of cases, MRI changed management or the surgical approach relative to the clinical evaluation of an interdisciplinary team. Thus, dynamic pelvic floor MRI represents an essential component of the evaluation for pelvic floor disorders.

Rationale and Objectives: The purpose of this study was to evaluate the feasibility and technical quality of a zoomed three-dimensional (3D) turbo spin-echo (TSE) sampling perfection with application optimized contrasts using different flip-angle evolutions (SPACE) sequence of the lumbar spine., Materials and Methods: In this prospective feasibility study, nine volunteers underwent a 3-T magnetic resonance examination of the lumbar spine including 1) a conventional 3D T2-weighted (T2w) SPACE sequence with generalized autocalibrating partially parallel acquisition technique acceleration factor 2 and 2) a zoomed 3D T2w SPACE sequence with a reduced field of view (reduction factor 2). Images were evaluated with regard to image sharpness, signal homogeneity, and the presence of artifacts by two experienced radiologists. For quantitative analysis, signal-to-noise ratio (SNR) values were calculated., Results: Image sharpness of anatomic structures was statistically significantly greater with zoomed SPACE (P < .0001), whereas the signal homogeneity was statistically significantly greater with conventional SPACE (cSPACE; P = .0003). There were no statistically significant differences in extent of artifacts. Acquisition times were 8:20 minutes for cSPACE and 6:30 minutes for zoomed SPACE. Readers 1 and 2 selected zSPACE as the preferred sequence in five of nine cases. In two of nine cases, both sequences were rated as equally preferred by both the readers. SNR values were statistically significantly greater with cSPACE., Conclusions: In comparison to a cSPACE sequences, zoomed SPACE imaging of the lumbar spine provides sharper images in conjunction with a 25% reduction in acquisition time., (Copyright © 2015 AUR. Published by Elsevier Inc. All rights reserved.)

Purpose: CAIPIRINHA-Dixon-TWIST (CDT)-VIBE is a robust method for abdominal magnetic resonance imaging providing both high spatial and high temporal resolution. The purpose of this study was to examine the influence of different gadolinium based contrast agents (GBCA) on image quality (IQ) with CDT-VIBE., Materials and Methods: In this IRB-approved, retrospective, inter-individual comparison study, 86 patients scanned at 3T were included. Within 28s, 14 high-resolution 3D datasets were acquired using CDT-VIBE. 37 patients received 0.1mmol/kg gadoterate meglumine, 28 patients 0.1mmol/kg gadobutrol, and 19 patients 0.1mL/kg gadoxetic acid. Two blinded, board-certified radiologists assessed the image quality on a 5 point scale, as well as the number of hepatic arterial dominant (HAD) phases., Results: Regardless of the GBCA utilized, CDT-VIBE resulted in good IQ in terms of best IQ achieved among all 14 datasets (gadobutrol 4.3, gadoterate meglumine 3.9, gadoxetic acid 3.7). With respect to worst IQ, the three groups showed statistically significant differences with gadobutrol receiving the highest rating (3.6) and gadoxetic acid the lowest (2.4) (gadoterate meglumine 3.0; 0.0014

Objectives: To evaluate the feasibility of zoomed diffusion-weighted EPI (z-EPI) in the head and neck in a healthy volunteer population and to compare to conventional single-shot EPI (c-EPI)., Material and Methods: Nine volunteers were included in this prospective, IRB-approved study. Examinations were performed on a 3 T-MR system equipped with a two-channel, fully-dynamic parallel transmit array. The acquired sequences consisted of a T2w-TSE, a c-EPI, and two z-EPI acquisitions. For quantitative assessment of distortion artefacts, DW images were fused with T2-TSE images. Misregistration of DW images with T2-TSE images was assessed in the cervical spine. For qualitative assessment, two readers ranked c-EPI and z-EPI sequences in terms of susceptibility artefacts, image blur, and overall imaging preference. ADC values of several anatomical regions were calculated and compared between sequences., Results: Mean maximum distortion with the c-EPI was 5.9 mm ± 1.6 mm versus 2.4 mm ± 1 mm (p < 0.05) with z-EPI. Both readers found more blur and susceptibility artefacts in every case with c-EPI. No statistically significant differences in calculated ADC values were observed., Conclusion: z-EPI of the head and neck leads to substantial image quality improvements relative to c-EPI due to a reduction in susceptibility artefacts and image blur., Key Points: • Zoomed DWI is feasible in the head and neck. • Image quality improves substantially with zoomed DWI of the neck. • Zoomed DWI exhibits markedly reduced susceptibility artefacts.

Objectives: After allogeneic stem cell transplantation (SCT), a reliable diagnosis of acute graft versus host disease (aGvHD) is essential for an early and successful treatment. It is the aim of this analysis to assess intestinal aGvHD by magnetic resonance imaging (MRI)., Methods: Prior to allogeneic SCT, 64 consecutive patients underwent abdominal MRI examination on a 3 T MR system, including axial and coronal T2w sequences and a three-dimensional dynamic T1w, contrast enhanced sequence. After SCT, 20 patients with suspected aGvHD received a second MRI as well as an endoscopic examination., Results: Nine patients suffered from histologically proven intestinal aGvHD. In eleven patients intestinal aGvHD was excluded. In all aGvHD patients typical MRI findings with long-segment bowel wall thickening--always involving the terminal ileum--with profound submucosal oedema, were detected. The bowel wall was significantly thickened in patients with intestinal aGvHD. Bowel contrast enhancement spared the submucosa while demonstrating strong mucosal hyperemia., Conclusions: In intestinal aGvHD, a characteristic MR-appearance can be detected. This MRI pattern might facilitate an early and non-invasive diagnosis of intestinal aGvHD. MRI might thus be used as a sensitive tool to rule out or support the clinical diagnosis of aGvHD., Key Points: • Acute intestinal graft versus host disease (aGvHD) can be assessed by MRI. • The aGvHD of the bowel demonstrates a characteristic MR imaging pattern. • Bowel wall shows extensive long-segment wall thickening with profound submucosal oedema. • Terminal ileum seems invariably affected; other bowel segments show variable involvement. • Colonoscopy in suspected aGvHD should include inspection of terminal ileum.

Purpose: The purpose of this study is two-fold. First, to evaluate, whether functional rectal MRI techniques can be analyzed in a reproducible manner by different readers and second, to assess whether different clinical and pathologic T and N stages can be differentiated by functional MRI measurements., Materials and Methods: 54 patients (38 men, 16 female; mean age 63.2 ± 12.2 years) with pathologically proven rectal cancer were included in this retrospective IRB-approved study. All patients were referred for a multi-parametric MRI protocol on a 3 Tesla MR-system, consisting of a high-resolution, axial T2 TSE sequence, DWI and perfusion imaging (plasma flow -s PFTumor) prior to any treatment. Two experienced radiologists evaluated the MRI measurements, blinded to clinical data and outcome. Inter-reader correlation and the association of functional MRI parameters with c- and p-staging were analyzed., Results: The inter-reader correlation for lymph node (ρ 0.76-0.94; p<0.0002) and primary tumor (ρ 0.78-0.92; p<0.0001) apparent diffusion coefficient and plasma flow (PF) values was good to very good. PFTumor values decreased with cT stage with significant differences identified between cT2 and cT3 tumors (229 versus 107.6 ml/100ml/min; p=0.05). ADCTumor values did not differ significantly. No substantial discrepancies in lymph node ADCLn values or short axis diameter were found among cN1-3 stages, whereas PFLn values were distinct between cN1 versus cN2 stages (p=0.03). In the patients without neoadjuvant RCT no statistically significant differences in the assessed functional parameters on the basis of pathologic stage were found., Conclusion: This study illustrates that ADC as well as MR perfusion values can be analyzed with good interobserver agreement in patients with rectal cancer. Moreover, MR perfusion parameters may allow accurate differentiation of tumor stages. Both findings suggest that functional MRI parameters may help to discriminate T and N stages for clinical decision making., (Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.)

Purpose: To compare enhancement characteristics and image quality of two macrocyclic gadolinium chelates, gadoterate meglumine and gadobutrol, in low-dose, time-resolved MRA of the calf station., Materials and Methods: 100 consecutive patients with peripheral arterial disease (stages II-IV) were retrospectively analysed. Fifty patients were included in each group - 32 men and 18 women for gadobutrol (mean age 67 years) and 34 men, 16 women for gadoterate meglumine (mean age 64 years). 0.03 mmol/kg bw of either gadobutrol or gadoterate meglumine was injected. Gadobutrol was diluted 1 ∶ 1 with normal saline (0.9% NaCl) to provide similar injection volume and bolus geometry compared to the undiluted 0.5 M dose of gadoterate meglumine. Signal-to-noise-ratio (SNR), contrast-to-noise-ratio (CNR) and image quality were analysed and compared between the two groups., Results: Mean SNR ranged from 83.0 ± 46.7 (peroneal artery) to 96.4 ± 64.5 (anterior tibial artery) for gadobutrol, and from 37.6 ± 13.8 (peroneal artery) to 45.3 ± 16.4 (anterior tibial artery) for the gadoterate meglumine group (p<0.0001). CNR values ranged from 30.1 ± 20.1 (peroneal artery) to 37.6 ± 26.0 (anterior tibial artery) for gadobutrol and from 14.9 ± 8.0 (peroneal artery) to 18.6 ± 16.4 (anterior tibial artery) for gadoterate meglumine (p<0.0001). No significant difference in image quality was found except for the peroneal arteries (p = 0.006 and p = 0.04). Interreader agreement was excellent (kappa 0.87-0.93)., Conclusion: The significantly better enhancement as assessed by SNR and CNR provided by gadobutrol compared to gadoterate meglumine does not translate into substantial differences in image quality in an equimolar, low-dose, time-resolved MRA protocol of the calves.

Purpose: To evaluate the diagnostic accuracy of a nonenhanced electrocardiograph-gated quiescent-interval single shot MR-angiography (QISS-MRA) at 3 Tesla with contrast-enhanced MRA (CE-MRA) and digital subtraction angiography (DSA) serving as reference standard., Materials and Methods: Following institutional review board approval, 16 consecutive patients with peripheral arterial disease underwent a combined peripheral MRA protocol consisting of a large field-of-view QISS-MRA, continuous table movement MRA, and an additional time-resolved MRA of the calves. DSA correlation was available in eight patients. Image quality and degree of stenosis was assessed. Sensitivity and specificity of QISS-MRA was evaluated with CE-MRA and DSA serving as the standards of reference and compared using the Fisher exact test., Results: With the exception of the calf station, image quality with QISS-MRA was rated statistically significantly less than that of CE-MRA (P < 0.05, P = 0.17, and P = 0.6, respectively). A greater percentage of segments were not accessible with QISS-MRA (19.5-20.1%) in comparison to CE-MRA (10.9%). Relative to DSA, sensitivity for QISS-MRA was high (100% versus 91.2% for CE-MRA, P = 0.24) in the evaluated segments; however, specificity (76.5%) was substantially less than that of CE-MRA (94.6%, P = 0.003)., Conclusion: Overall image quality and specificity of QISS-MRA at 3T are diminished relative to CE-MRA. However, when image quality is adequate, QISS-MRA has high sensitivity and, thus, has potential use in patients with contraindications to gadolinium., (Copyright © 2013 Wiley Periodicals, Inc.)

Background: Implementation of DWI in the abdomen is challenging due to artifacts, particularly those arising from differences in tissue susceptibility. Two-dimensional, spatially-selective radiofrequency (RF) excitation pulses for single-shot echo-planar imaging (EPI) combined with a reduction in the FOV in the phase-encoding direction (i.e. zooming) leads to a decreased number of k-space acquisition lines, significantly shortening the EPI echo train and potentially susceptibility artifacts., Purpose: To assess the feasibility and image quality of a zoomed diffusion-weighted EPI (z-EPI) sequence in MR imaging of the pancreas. The approach is compared to conventional single-shot EPI (c-EPI)., Material and Methods: 23 patients who had undergone an MRI study of the abdomen were included in this retrospective study. Examinations were performed on a 3T whole-body MR system (Magnetom Skyra, Siemens) equipped with a two-channel fully dynamic parallel transmit array (TimTX TrueShape, Siemens). The acquired sequences consisted of a conventional EPI DWI of the abdomen and a zoomed EPI DWI of the pancreas. For z-EPI, the standard sinc excitation was replaced with a two-dimensional spatially-selective RF pulse using an echo-planar transmit trajectory. Images were evaluated with regard to image blur, respiratory motion artifacts, diagnostic confidence, delineation of the pancreas, and overall scan preference. Additionally ADC values of the pancreatic head, body, and tail were calculated and compared between sequences., Results: The pancreas was better delineated in every case (23/23) with z-EPI versus c-EPI. In every case (23/23), both readers preferred z-EPI overall to c-EPI. With z-EPI there was statistically significantly less image blur (p<0.0001) and respiratory motion artifact compared to c-EPI (p<0.0001). Diagnostic confidence was statistically significantly better with z-EPI (p<0.0001). No statistically significant differences in calculated ADC values were observed between the two sequences., Conclusion: Zoomed diffusion-weighted EPI leads to substantial image quality improvements with reduction of susceptibility artifacts in pancreatic DWI.

Purpose: To compare a fast 3D VIBE sequence with Dixon fat saturation and CAIPIRINHA acceleration techniques (3D VIBE(CAIPI-DIXON)) to a standard 2D FLASH sequence with spectral fat saturation and conventional GRAPPA acceleration technique (2D Flash(GRAPPA-fs)) for non-enhanced imaging of the pancreas., Methods and Materials: In this retrospective, institutional review board-approved intra-individual comparison study, 29 patients (7 female, 22 male; mean age 60.4 ± 20.9 years) examined on a 48-channel 3.0-T MR system (MAGNETOM Skyra VD 13, Siemens Healthcare Sector, Germany) were included. 3D VIBE(CAIPI-DIXON) (TR/TE-3.95/2.5+1.27 ms; spatial resolution-1.2 × 1.2 × 3.0 mm(3); CAIPIRINHA 2 × 2 [1], acquisition time-0:12 min) and 2D Flash(GRAPPA-fs) (TR/TE-195/3.69 ms; 1.2 × 1.2 × 3.0 mm(3); GRAPPA 2, 3 × 0:21 min) sequences were performed in each subject in random order prior to the administration of an intravenous contrast agent. Two radiologists evaluated the images with regard to diagnostic preference. Semi-quantitative signal ratios were calculated for the pancreas versus the liver, spleen, muscle, and visceral fat. Inter-reader agreement was calculated using unweighted Cohen's kappa. Signal ratio results were analyzed using a univariate analysis of variance. Additional signal-to-noise (SNR) measurements were performed in a phantom., Results: 3D VIBE(CAIPI-DIXON) was preferred in 72.4% (both readers) and 2D Flash(GRAPPA-fs) in 3.4%/6.9% (reader 1/2) of cases with a kappa value of 0.756. The main reasons for this preference were homogenous fat saturation with 3D VIBE(CAIPI-DIXON) and reduced motion artifacts due to a faster acquisition, leading to improved delineation of the pancreas. Signal ratios of pancreatic to fat signal for 3D VIBE(CAIPI-DIXON) (10.08 ± 3.48) and 2D Flash(GRAPPA-fs) (6.53 ± 3.07) were statistically different (P<.001). However, no additional statistically significant differences in signal ratios were identified (range: 0.73 ± 0.18 to 1.37 ± 0.40; .514

Objective: To evaluate the feasibility of in vivo (23)Na imaging of the corticomedullary (23)Na gradient and to measure (23)Na transverse relaxation times (T2*) in human kidneys., Methods: In this prospective, IRB-approved study, eight healthy volunteers (4 female, 4 male; mean age 29.4 ± 3.6 years) were examined on a 7-T whole-body MR system using a (23)Na-only spine-array coil. For morphological (23)Na-MRI, a 3D gradient echo (GRE) sequence with a variable echo time scheme (vTE) was used. T2* times were calculated using a multiecho 3D vTE-GRE approach. (23)Na signal-to-noise ratios (SNR) were given on a pixel-by-pixel basis for a 20-mm section from the cortex in the direction of the medulla. T2* maps were calculated by fitting the (23)Na signal decay monoexponentially on a pixel-by-pixel basis, using least squares fit., Results: Mean corticomedullary (23)Na-SNR increased from the cortex (32.2 ± 5.6) towards the medulla (85.7 ± 16.0). The SNR increase ranged interindividually from 57.2% to 66.3%. Mean (23)Na-T2* relaxation times differed statistically significantly (P < 0.001) between the cortex (17.9 ± 0.8 ms) and medulla (20.6 ± 1.0 ms)., Conclusion: The aim of this study was to evaluate the feasibility of in vivo (23)Na MRI of the corticomedullary (23)Na gradient and to measure the (23)Na T2* relaxation times of human kidneys at 7 T., Key Points: • High field MR offers new insights into renal anatomy and physiology. • (23) Na MRI of healthy human kidneys is feasible at ultra-high field. • Renal (23) Na concentration increases from the cortex in the medullary pyramid direction. • In vivo measurements of renal (23) Na-T2* times are demonstrated at 7.0 T.

Purpose: The purpose of this prospective study was to assess physiologic changes in the renal corticomedullary (23)Na-concentration ([(23)Na]) gradient with (23)Na-MRI at 3.0T in patients with central diabetes insipidus (CDI) before and after intranasal administration of 20 μg desmopressin (DDAVP)., Methods and Materials: Four patients with CDI (all male, mean age 60.2 years) were included in this IRB-approved study. For (23)Na-imaging, a 3D density adapted, radial GRE-sequence (TE = 0.55 ms; TR = 120 ms; projections = 8,000; spatial resolution = 5 × 5 × 5 mm(3)) was used in combination with a dedicated (23)Na-coil and reference phantoms. The corticomedullary [(23)Na] gradient (in mmol/L/mm) was calculated pixel-by-pixel along a linear region-of-interest (ROI) spanning from the renal cortex in the direction of the medulla. Mean ± SDs of [(23)Na] were calculated for each patient as well as for the entire group., Results: Mean [(23)Na] increased along the corticomedullary gradient from the cortex (pre-DDAVP 38.0 ± 6.3 mmol/L vs. post-DDAVP 30.7 ± 3.5 mmol/L) to the medulla (pre-DDAVP 71.6 ± 14.8 mmol/L vs. post-DDAVP 59.7 ± 10.8 mmol/L). The overall mean decrease of [(23)Na] after DDAVP administration was 17.1 ± 1.1 %., Conclusion: (23)Na-MRI with state-of-the-art techniques at 3T depicts the physiologic renal response to the administration of desmopressin in patients with central diabetes insipidus.

Objectives: Contrast-enhanced MRI can only distinguish to a limited extent between malignant and benign focal renal lesions. The aim of this meta-analysis is to review renal diffusion-weighted imaging (DWI) to compare apparent diffusion coefficient (ADC) values for different renal lesions that can be applied in clinical practice., Methods: A PubMed search was performed to identify relevant articles published 2004-2011 on renal DWI of focal renal lesions. ADC values were extracted by lesion type to determine whether benign or malignant. The data table was finalised in a consensus read. ADC values were evaluated statistically using meta-regression based on a linear mixed model. Two-sided P value <5 % indicated statistical significance., Results: The meta-analysis is based on 17 studies with 764 patients. Renal cell carcinomas have significant lower ADC values than benign tissue (1.61 ± 0.08 × 10(-3) mm(2)/s vs 2.10 ± 0.09 × 10(-3) mm(2)/s; P < 0.0001). Uroepithelial malignancies can be differentiated by lowest ADC values (1.30 ± 0.11 × 10(-3) mm(2)/s). There is a significant difference between ADC values of renal cell carcinomas and oncocytomas (1.61 ± 0.08 × 10(-3) mm(2)/s vs 2.00 ± 0.08 × 10(-3) mm(2)/s; P < 0.0001)., Conclusions: Evaluation of ADC values can help to determine between benign and malignant lesions in general but also seems able to differentiate oncocytomas from malignant tumours, hence potentially reducing the number of unnecessarily performed nephrectomies., Key Points: • This meta-analysis assesses the role of diffusion-weighted MRI in renal lesions. • ADC values obtained by DW MRI have been compared for different renal lesions. • ADC values can help distinguish between benign and malignant tumours. • Differentiating oncocytomas from malignant tumours can potentially reduce inappropriate nephrectomies.

This study compared features of the metabolic syndrome between healthy controls and depressed patients without activation of the hypothalamus-pituitary-adrenal (HPA) system. After exclusion of non-suppressors to 1mg dexamethasone, we included 20 depressed inpatients and 34 healthy controls in the analyses. We assessed HPA system activity (diurnal saliva cortisol profile, cortisol excretion), normetanephrine excretion as well as fasting glucose, lipid profile and blood pressure. With regard to body composition, we measured waist circumference as well as visceral fat and adrenal volume by magnetic resonance (MR) imaging. Five depressed patients (25%) and five healthy controls (15%) fulfilled the criteria of the metabolic syndrome according NCEP-ATP-III. Depression was significantly related with fasting glucose and negatively associated with mean blood pressure (BP) and, by trend, with low HDL-cholesterol. We conclude that depressed patients may have modest metabolic disturbances even in the complete absence of activation of stress-responsive systems. Hence some metabolic disturbances in depressed patients may not be explicable by HPA activation. Additional factors are required to mediate the link between affective and metabolic disorders., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

Objectives: The purpose of this prospective study was to assess the normal physiologic ranges of the renal corticomedullary 23Na-concentration ([23Na]) gradient at 3.0T in healthy volunteers. The corticomedullary [23Na] gradient was correlated with other functional MR imaging parameters--blood oxygenation level dependent (BOLD) and diffusion-weighted imaging (DWI)--and to individual and physiologic parameters--age, gender, estimated glomerular filtration rate (eGFR), body mass index (BMI), and blood serum sodium concentration ([23Na]serum)., Methods and Materials: 50 healthy volunteers (30 m, 20 w; mean age: 29.2 years) were included in this IRB-approved study, without a specific a priori preparation in regard to water or food intake. For 23Na-imaging a 3D density adapted, radial gradient echo (GRE)-sequence (spatial resolution=5×5×5 mm3) was used in combination with a dedicated 23Na-coil and 23Na-reference phantoms. [23Na] values of the corticomedullary [23Na] gradient were measured by placement of a linear region of interest (20×1 mm2) from the renal cortex in the direction of the renal medulla. By using external standard reference phantoms, [23Na] was calculated in mmol/L of wet tissue volume (mmol/l WTV). Axial diffusion-weighted images (spatial resolution=1.7×1.7×5.0 mm3) and 2D GRE BOLD images (spatial resolution=1.2×1.2×4.0 mm3) were acquired. Mean values±standard deviations for [23Na], apparent diffusion coefficient (ADC) values, and R2* values were computed for each volunteer. The corticomedullary 23Na-concentration gradient (in mmol/l/mm) was calculated along the area of linear concentration increase from the cortex in the direction of the medulla. Correlations between the [23Na] and DWI, BOLD, and the physiologic parameters were assessed with Pearson correlation coefficients., Results: The mean corticomedullary [23Na] for all healthy volunteers increased from the renal cortex (58±17 mmol/l WTV) in the direction of the medulla (99±18 mmol/l WTV). The inter-individual differences ranged from respective cortical and medullary values of 27 and 63 mmol/L WTV to 126 and 187 mmol/L WTV. No statistically significant differences in renal [23Na] were found based on differences in individual or physiologic parameters (age, gender, [23Na]serum, BMI, GFR). No ADC or R2* gradients were identified, and [23Na] did not correlate with these parameters., Conclusion: Renal corticomedullary [23Na] values increase from the cortex in the direction of the medullary pyramid, demonstrating wide inter-individual ranges and no significant correlations with age, gender, [23Na]serum, BMI, GFR, ADC, or R2* values. For future clinical evaluations, an approach relying on renal stimulation (e.g. pharmacologically induced diuresis) may be applicable to account for wide inter-individual ranges of normal [23Na].

Objective: The purpose of this article is to evaluate the added diagnostic accuracy of time-resolved MR angiography (MRA) of the calves compared with continuous-table-movement MRA in patients with symptomatic lower extremity peripheral artery disease (PAD) using digital subtraction angiography (DSA) correlation., Materials and Methods: Eighty-four consecutive patients with symptomatic PAD underwent a low-dose 3-T MRA protocol, consisting of continuous-table-movement MRA, acquired from the diaphragm to the calves, and an additional time-resolved MRA of the calves; 0.1 mmol/kg body weight (bw) of contrast material was used (0.07 mmol/kg bw for continuous-table-movement MRA and 0.03 mmol/kg bw for time-resolved MRA). Two radiologists rated image quality on a 4-point scale and stenosis degree on a 3-point scale. An additional assessment determined the degree of venous contamination and whether time-resolved MRA improved diagnostic confidence. The accuracy of stenosis gradation with continuous-table-movement and time-resolved MRA was compared with that of DSA as a correlation. Overall diagnostic accuracy was calculated for continuous-table-movement and time-resolved MRA., Results: Median image quality was rated as good for 578 vessel segments with continuous-table-movement MRA and as excellent for 565 vessel segments with time-resolved MRA. Interreader agreement was excellent (κ = 0.80-0.84). Venous contamination interfered with diagnosis in more than 60% of continuous-table-movement MRA examinations. The degree of stenosis was assessed for 340 vessel segments. The diagnostic accuracies (continuous-table-movement MRA/time-resolved MRA) combined for the readers were obtained for the tibioperoneal trunk (84%/93%), anterior tibial (69%/87%), posterior tibial (85%/91%), and peroneal (67%/81%) arteries. The addition of time-resolved MRA improved diagnostic confidence in 69% of examinations., Conclusion: The addition of time-resolved MRA at the calf station improves diagnostic accuracy over continuous-table-movement MRA alone in symptomatic patients with PAD.

Purpose: To evaluate diffusion-weighted MR imaging (DWI-MRI) for the detection and assessment of infectious renal disease., Materials and Methods: Twenty-one patients with suspicious increased signal intensity of the kidneys on DWI sequences and corresponding ADC decrease were identified. Sixty patients without clinical signs of renal infection served as a control group. All patients were examined with the following sequences: EPI-DWI (0/400/800 s/mm(2)), T2w HASTE, and T1w VIBE after intravenous injection of Gd-chelate. Confirmation of renal infection was established on the basis of clinical criteria. T1w and T2w images were assessed and compared to DWI for the presence of altered signal, and the degree of the visibility of pathology was graded on an ordinal three-point scale., Results: In all 21 patients with positive DWI findings a renal infection could be confirmed. T2w imaging and contrast-enhanced T1w imaging displayed obvious pathologic signal in 3/21 (14%) and 11/19 (58%) patients and slightly pathologic signal in 17/21 (81%) and 7/19 (37%), respectively. The median visibility score of 2 for the DWI and the T1w images was significantly higher than the score of 1 for the T2w imaging, P = 0.0001 (DWI versus T2w) and P = 0.078 (T1w versus T2w)., Conclusion: DWI of the kidneys seems to be highly sensitive for the detection of infections within the kidney.

Background: To evaluate the feasibility and additional diagnostic benefit of a high-resolution steady state 3D-volume interpolated breath-hold exam (VIBE) sequence between a continuous table movement (CTM) MR angiography of the entire runoff vasculature and a time-resolved (TWIST) MRA of the calves., Methods: In this retrospective IRB approved study 224 patients (72 women, 152 men, mean age 67.29 ± 13.9) were included who had undergone a low-dose MR angiographic protocol at 3T (Siemens TimTrio) after injection of 0.1 mmol/kg gadobutrol including a CTM MRA, a time-resolved MRA of the calf station and a steady state 3D VIBE sequence prior to the time-resolved MRA. One board-certified radiologist rated the image quality of the steady state VIBE sequences on an ordinal three point scale (excellent, good, poor) and analyzed the images for additional diagnostic findings of and beyond the vascular system in comparison to the CTM MRA and the time-resolved MRA. Descriptive statistics and demographic patient data were used for further evaluation., Results: The image quality of the steady state imaging of the pelvis, upper and lower leg was excellent in up to 88%, 84% and 47%, respectively, while poor image quality was only detected in the upper (2%) and lower leg (6%). An additional diagnostic benefit was found in 44% of the patients overall. The most common relevant pathologies included inflammatory processes of the soft tissues (26%), thrombi (14%), abscesses (13%) and tumors (11%). In subgroups of patients above the age of 60, 65, 70, 75 and 80 years an additional pathology was found in 50% 33%, 44%, 65% and 58%, respectively. There was no significant difference in terms of additional findings between men and women (46% and 39%, p > 0.05) and inpatients and outpatients (42% and 45%, p > 0.05)., Conclusion: Steady state imaging is also feasible with extracellular contrast agents with good image quality yielding additional diagnostic findings in up to 44% and above in patients older than 60 years of age irrespective of gender or patient status. Given the short acquisition time of 4 minutes this sequence could be added to all peripheral MRA exams.

Aim: To retrospectively and prospectively compare diffusion-weighted (DW) images in the abdomen in a 1.5T system and 3.0T systems with and without two-channel functionality for B1 shimming., Methods: DW images of the abdomen were obtained on 1.5T and 3.0T (with and without two-channel functionality for B1 shimming) scanners on 150 patients (retrospective study population) and 10 volunteers (prospective study population). Eight regions were selected for clinical significance or artifact susceptibility (at higher field strengths). Objective grading quantified signal-to-noise ratio (SNR), and subjective evaluation qualified image quality, ghosting artifacts, and diagnostic value. Statistical significance was calculated using χ(2) tests (categorical variables) and independent two-sided t tests or Mann-Whitney U tests (continuous variables)., Results: The 3.0T using dual-source parallel transmit (dpTX 3.0T) provided the significantly highest SNRs in nearly all regions. In regions susceptible to artifacts at higher field strengths (left lobe of liver, head of pancreas), the SNR was better or similar to the 1.5T system. Subjectively, both dpTX 3.0T and 1.5T systems provided higher image quality, diagnostic value, and less ghosting artifact (P < 0.01, most values) compared to the 3.0T system without dual-source parallel transmit (non-dpTX 3.0T)., Conclusion: The dpTX 3.0T scanner provided the highest SNR. Its image quality, lack of ghosting, and diagnostic value were equal to or outperformed most currently used systems.

Purpose: The purpose of this study was to compare automated, motion-corrected, color-encoded (AMC) perfusion maps with qualitative visual analysis of adenosine stress cardiovascular magnetic resonance imaging for detection of flow-limiting stenoses., Materials and Methods: Myocardial perfusion measurements applying the standard adenosine stress imaging protocol and a saturation-recovery temporal generalized autocalibrating partially parallel acquisition (t-GRAPPA) turbo fast low angle shot (Turbo FLASH) magnetic resonance imaging sequence were performed in 25 patients using a 3.0-T MAGNETOM Skyra (Siemens Healthcare Sector, Erlangen, Germany). Perfusion studies were analyzed using AMC perfusion maps and qualitative visual analysis. Angiographically detected coronary artery (CA) stenoses greater than 75% or 50% or more with a myocardial perfusion reserve index less than 1.5 were considered as hemodynamically relevant. Diagnostic performance and time requirement for both methods were compared. Interobserver and intraobserver reliability were also assessed., Results: A total of 29 CA stenoses were included in the analysis. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy for detection of ischemia on a per-patient basis were comparable using the AMC perfusion maps compared to visual analysis. On a per-CA territory basis, the attribution of an ischemia to the respective vessel was facilitated using the AMC perfusion maps. Interobserver and intraobserver reliability were better for the AMC perfusion maps (concordance correlation coefficient, 0.94 and 0.93, respectively) compared to visual analysis (concordance correlation coefficient, 0.73 and 0.79, respectively). In addition, in comparison to visual analysis, the AMC perfusion maps were able to significantly reduce analysis time from 7.7 (3.1) to 3.2 (1.9) minutes (P < 0.0001)., Conclusions: The AMC perfusion maps yielded a diagnostic performance on a per-patient and on a per-CA territory basis comparable with the visual analysis. Furthermore, this approach demonstrated higher interobserver and intraobserver reliability as well as a better time efficiency when compared to visual analysis.

Purpose: The purpose of this study was to assess the feasibility and image quality of a novel, highly accelerated T1-weighted sequence for time-resolved imaging of the abdomen during the first pass of contrast media transit using controlled aliasing in parallel imaging results in higher acceleration (CAIPIRINHA) under sampling, view-sharing techniques, and Dixon water-fat separation (CAIPRINHA-Dixon-time-resolved imaging with interleaved stochastic trajectories-volumetric interpolated breath-hold examination [CDT-VIBE])., Materials and Methods: In this retrospective, institutional review board-approved study, 47 patients (median age, 62 years; 25 men, 22 women) scanned on a 3.0-T magnetic resonance system (Skyra; Siemens) were included. The CDT-VIBE (repetition time/echo time1/echo time2, 4.1/1.33/2.56 milliseconds; acquisition time, 29 seconds) was used in place of the standard arterial phase acquisition and started 15 seconds after the injection of 0.1 mmol/kg Gd-DOTA (Dotarem, Guerbet). Within 29 seconds, 14 high spatial resolution (1.2 × 1.2 × 3 mm) 3-dimensional data sets were acquired and reconstructed using view sharing (temporal resolution, 2.1 seconds). The CDT-VIBE images were evaluated independently by 2 blinded, experienced radiologists with regard to image quality and the number of hepatic arterial-dominant phases present on an ordinal 5-point scale (5, excellent; 1, nondiagnostic). Added diagnostic information with CDT-VIBE relative to portal venous phase VIBE was assessed., Results: In all patients, CDT-VIBE measurements were successfully acquired. The image quality was diagnostic in 46 of the 47 patients. Both readers assessed the highest image quality present in the data sets with a median score of 4 (range, 3-5 for both readers; κ, 0.789) and the worst image quality with a median score of 3 (range, 1-4 for both readers; κ, 0.689). With a range between 1 and 8 (median, 5), hepatic arterial-dominant data sets (of the 14 acquired) were obtained in each case. There was an added diagnostic value with CDT-VIBE in 10 of the 47 patients (21%)., Conclusions: The CDT-VIBE is a robust approach allowing, for the first time, dynamic imaging of the upper abdomen with high temporal resolution and preservation of high spatial resolution.