[Structured reporting in daily practice-status quo and future]. / Strukturierte Befundung in der Praxis ­ Status und Ausblick.

CLINICAL/METHODICAL ISSUE: Introduction and application of structured reporting in radiology private practice. STANDARD RADIOLOGICAL METHODS: Ultrasound (US), magnetic resonance imaging (MRI), computed tomography (CT), digital x­ray (DR), mammography (MG). METHODOLOGICAL INNOVATIONS: Structuring and predefinition of entire reports and report parts. PERFORMANCE: Structured reporting in radiology presumably allows for higher report quality, reproducibility and easier access to data mining. Also the communication with the referring physicians can be improved. Although these advantages are well acknowledged, structured reporting does not prevail in private radiology practices. This article sheds light on the current situation of structured reporting in radiology private practice and provides information for the faltering implementation as well as perspective for individual potential solutions to overcome this situation. ACHIEVEMENTS: Structured reporting is not yet standard. Growing acceptance of structured reporting can be expected. PRACTICAL RECOMMENDATIONS: The application of structured reporting can improve report quality. The use of structured reporting should be considered for common examinations.

[Does SARS-CoV-2 cause lung inflammation even in mild clinical courses? : A multicenter report from outpatient care]. / Verursacht SARS-CoV-2 auch bei milden klinischen Verläufen eine Lungenentzündung? : Ein Multicenterbericht aus der ambulanten Versorgung.

OBJECTIVE: In spring 2020 imaging findings of the lungs were found in several radiological practices and in outpatient clinic patients, which indicated acute or previous viral pneumonia. It was striking that many of the patients affected had only mild symptoms. In this case study it was investigated to what extent SARS-CoV­2 can cause lung involvement even with minor symptoms. MATERIAL AND METHODS: In this study five outpatient radiological centers and two inpatient hospitals in North Rhine-Westphalia and Baden-Württemberg in Germany were involved. The retrospective analysis included outpatients with radiologically detected viral pneumonia, who were examined in March or April 2020. The clinical symptoms were divided into severity levels 1-5 using a simplified clinical score. The lung images were evaluated with respect to features specific for COVID-19 . The presence of a SARS-CoV­2 infection was verified using PCR, antibody testing and/or typical computed tomography (CT) morphology. RESULTS: A total of 50 patients were included, all of whom had radiological signs of viral pneumonia. The majority had no or only few non-specific symptoms (26/50). This was followed by mild symptoms of a flu-like infection (17/50). Severe forms were rare in outpatients (7/50). Detection of COVID-19 was successful in 30/50 cases using PCR and in 4/50 cases using an antibody test. In 16/50 cases the diagnosis was based on typical CT criteria and on the typical COVID patient history. CONCLUSION: A SARS-CoV­2 infection leads to lung involvement more often than previously assumed, namely not only in severely ill hospitalized patients but also in cases with only mild or even non-specific symptoms.

Magnetic resonance imaging reveals distinct bone marrow patterns in indolent and advanced systemic mastocytosis.

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.

Diagnosing autoimmune pancreatitis with the Unifying-Autoimmune-Pancreatitis-Criteria.

BACKGROUND/OBJECTIVES: We had developed the Unifying-Autoimmune-Pancreatitis-Criteria (U-AIP) to diagnose autoimmune pancreatitis (AiP) within the M-ANNHEIM classification of chronic pancreatitis. In 2011, International-Consensus-Diagnostic-Criteria (ICDC) to diagnose AiP have been published. We had applied the U-AIP long before the ICDC were available. The aims of the study were, first, to describe patients with AiP diagnosed by the U-AIP; second, to compare diagnostic accuracies of the U-AIP and other diagnostic systems; third, to evaluate the clinical applicability of the U-AIP. METHODS: From 1998 until 2008, we identified patients with AiP using U-AIP, Japanese-, Korean-, Asian-, Mayo-HISORt-, Revised-Mayo-HISORt- and Italian-criteria. We retrospectively verified the diagnosis by ICDC and Revised-Japanese-2011-criteria, compared diagnostic accuracies of all systems and evaluated all criteria in consecutive patients with pancreatitis (2009 until 2010, Pancreas-Outpatient-Clinic-Cohort, n = 84). We retrospectively validated our diagnostic approach in consecutive patients with a pancreatic lesion requiring surgery (Surgical-Cohort, n = 98). RESULTS: Overall, we identified 21 patients with AiP. Unifying-Autoimmune-Pancreatitis-Criteria and ICDC presented the highest diagnostic accuracies (each 98.8%), highest Youden indices (each 0.95238), and highest proportions of diagnosed patients (each n = 20/21, U-AIP/ICDC vs. other diagnostic systems, p < 0.05, McNemar test). In the Pancreas-Outpatient-Clinic-Cohort, seven patients were diagnosed with AiP (n = 6 by U-AIP, n = 1 by Asian-criteria). International-Consensus-Diagnostic-Criteria confirmed the diagnosis in these individuals. Based on partial fulfillment of U-AIP, AiP was initially suspected in 13% (n = 10/77) of remaining patients from the Pancreas-Outpatient-Clinic-Cohort. In the Surgical-cohort, we identified one patient with AiP by U-AIP and ICDC. CONCLUSIONS: Unifying-Autoimmune-Pancreatitis-Criteria revealed a satisfactory clinical applicability and offered an additional approach to diagnose AiP.

Prevalence and Incidence of Autoimmune Pancreatitis in the Population Living in the Southwest of Germany.

BACKGROUND/AIMS: The prevalence and incidence of autoimmune pancreatitis (AiP) in those living in western countries are largely unknown. We aimed to determine the prevalence of AiP among patients with pancreatitis presenting to our tertiary referral center in Mannheim, Germany; and to estimate the incidence of AiP in the Southwest of Germany. METHODS: We performed a retrospective cross-sectional analysis and determined the prevalence of AiP in patients with acute pancreatitis (AP) or chronic pancreatitis (CP). Patients (n = 704; alcoholic pancreatitis n = 373, nonalcoholic pancreatitis n = 331) were stratified into the Retrospective-Pancreas-Cohort (RPC, period 1998-2008, n = 534) and the Pancreas-Clinic-Cohort (PCC, periods 2008-2010 and 2013-2014, n = 170, with detailed investigation for features of AiP). Diagnosis of AiP was established by International-Consensus-Diagnostic-Criteria and Unifying-Autoimmune-Pancreatitis-Criteria. RESULTS: In the RPC, the prevalence of AiP was 5.9% (n = 13/221) among individuals with nonalcoholic pancreatitis (n = 1/61 with AP, 1.6%; n = 12/160 with CP, 7.5%). In the PCC, the prevalence of AiP was 9.1% (n = 10/110) among patients with nonalcoholic pancreatitis (n = 2/24 with AP, 8.3%; n = 8/86 with CP, 9.3%), and 1.7% (n = 1/60) among subjects with alcoholic pancreatitis. We estimated the incidence of AiP with 0.29 per 100,000 population each year. CONCLUSION: The prevalence rate of AiP may account for 9% of patients with nonalcoholic pancreatitis but is almost never observed in patients with alcoholic pancreatitis. The incidence of AiP in Germany appears lower than 1 per 100,000 population.

Nonenhanced ECG-gated quiescent-interval single shot MRA: image quality and stenosis assessment at 3 tesla compared with contrast-enhanced MRA and digital subtraction angiography.

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.

In vivo sodium (23Na) imaging of the human kidneys at 7 T: preliminary results.

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.

Zoomed EPI-DWI of the head and neck with two-dimensional, spatially-selective radiofrequency excitation pulses.

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.

Assessment of acute intestinal graft versus host disease by abdominal magnetic resonance imaging at 3 Tesla.

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.

Microwave ablation of osteoid osteomas using dynamic MR imaging for early treatment assessment: preliminary experience.

PURPOSE: To evaluate the efficacy of microwave ablation for osteoid osteomas by using dynamic contrast-enhanced magnetic resonance (MR) imaging in early treatment assessment. MATERIALS AND METHODS: Ten patients (two female, eight male; mean age, 28 y; range, 16-47 y) presenting with osteoid osteomas were treated between June 2010 and December 2012 with the use of computed tomography (CT)-guided microwave ablation. Osteoid osteomas were found at the femoral neck (n = 4), tibia (n = 3), calcaneus (n = 1), navicular bone (n = 1), and dorsal rib (n = 1). Dynamic contrast-enhanced MR imaging at 3.0 T was performed 1 day before microwave ablation and again after ablation. The procedure was considered successful if the signal intensity (SI) of the lesion on MR imaging decreased by at least 50% and the patient was pain-free within 1 week of intervention. RESULTS: All patients were pain-free within 1 week after microwave ablation and remained so during the 6 months of follow-up. No major or minor complications developed. On average, SI of the lesions decreased by 75% (range, 55.5%-89.1%) after treatment. The difference in lesion SI before versus after ablation was significant by t test (P < .0001; confidence interval, 120.26-174.96) and Wilcoxon test (P = .0020). CONCLUSIONS: Microwave ablation treatment of osteoid osteoma was highly successful, without any complications observed. Dynamic contrast-enhanced MR imaging is a useful tool for diagnosing osteoid osteoma and evaluating treatment.

3T renal (23)Na-MRI: effects of desmopressin in patients with central diabetes insipidus.

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.

Assessment of glycosaminoglycan content in intervertebral discs using chemical exchange saturation transfer at 3.0 Tesla: preliminary results in patients with low-back pain.

OBJECTIVES: To evaluate glycosaminoglycan-dependent chemical exchange saturation transfer (gagCEST) imaging at 3-T magnetic resonance imaging (MRI) for quantification of glycosaminoglycan (GAG) content in intervertebral discs (IVDs) in patients with low-back pain (LBP). METHODS: Sixteen patients with LBP were examined in this Institutional Review Board-approved study using a clinical whole-body system. The MRI protocol included standard morphological imaging, sagittal T2-mapping and gagCEST imaging. IVD grading according to the Pfirrmann score and region-of-interest analysis of the annulus fibrosus (AF) and the nucleus pulposus (NP) in gagCEST and T2 maps were performed before data were statistically tested for correlations between imaging techniques and quantitative differences between different grades of IVD degeneration. RESULTS: GagCEST values of the NP were significantly (P < 0.001) lower in degenerative IVDs (Pfirrmann 3 + 4) compared with non-degenerative IVDs (Pfirrmann 1 + 2), but only a weak linear correlation (r = 0.299) with the T2 relaxation times was found. GagCEST values of the NP exhibited a moderate negative correlation with Pfirrmann grades (r = -0.449). CONCLUSIONS: The known loss of GAG in the NP with increasing grade of morphological degeneration can be assessed using gagCEST imaging at 3.0 T. The correlation with single Pfirrmann grades and T2 relaxation times only seems to be moderate, indicating a substantial difference in information provided by the techniques.

Evaluation of liver fat in the presence of iron with MRI using T2* correction: a clinical approach.

OBJECTIVES: To assess magnetic resonance imaging (MRI) with conventional chemical shift-based sequences with and without T2* correction for the evaluation of steatosis hepatitis (SH) in the presence of iron. METHODS: Thirty-one patients who underwent MRI and liver biopsy because of clinically suspected diffuse liver disease were retrospectively analysed. The signal intensity (SI) was calculated in co-localised regions of interest (ROIs) using conventional spoiled gradient-echo T1 FLASH in-phase and opposed-phase (IP/OP). T2* relaxation time was recorded in a fat-saturated multi-echo-gradient-echo sequence. The fat fraction (FF) was calculated with non-corrected and T2*-corrected SIs. Results were correlated with liver biopsy. RESULTS: There was significant difference (P < 0.001) between uncorrected and T2* corrected FF in patients with SH and concomitant hepatic iron overload (HIO). Using 5 % as a threshold resulted in eight false negative results with uncorrected FF whereas T2* corrected FF lead to true positive results in 5/8 patients. ROC analysis calculated three threshold values (8.97 %, 5.3 % and 3.92 %) for T2* corrected FF with accuracy 84 %, sensitivity 83-91 % and specificity 63-88 %. CONCLUSIONS: FF with T2* correction is accurate for the diagnosis of hepatic fat in the presence of HIO. Findings of our study suggest the use of IP/OP imaging in combination with T2* correction. KEY POINTS: • Magnetic resonance helps quantify both iron and fat content within the liver • T2* correction helps to predict the correct diagnosis of steatosis hepatitis • "Fat fraction" from T2*-corrected chemical shift-based sequences accurately quantifies hepatic fat • "Fat fraction" without T2* correction underestimates hepatic fat with iron overload.

Steady state vascular imaging with extracellular gadobutrol: evaluation of the additional diagnostic benefit in patients who have undergone a peripheral magnetic resonance angiography protocol.

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.

Impact of time-resolved MRA on diagnostic accuracy in patients with symptomatic peripheral artery disease of the calf station.

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.

Quantitative in vivo 23Na MR imaging of the healthy human kidney: determination of physiological ranges at 3.0T with comparison to DWI and BOLD.

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].

Value of diffusion-weighted MR imaging for the detection of nephritis.

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.

Renal BOLD-MRI does not reflect renal function in chronic kidney disease.

Renal blood oxygen level-dependent magnetic resonance imaging (BOLD-MRI) is a noninvasive fast technique to characterize renal function. Here we evaluated the impact of renal function on the relaxation rate (R2(*)) in the cortex and medulla to provide baseline data for further use of renal BOLD-MRI. This parameter was evaluated in 400 patients scheduled for abdominal imaging who underwent transversal blood oxygen level-dependent measurements with a multi-echo gradient-echo sequence with 12 echo times. The loss of phase coherence (T2(*)) maps were generated in which kidney regions of interest were selected to differentiate the medulla and cortex, and R2(*) was equated to 1/T2(*). Individual R2(*) values were, in turn, correlated to the eGFR (MDRD formula of 280 patients with available serum creatinine measurements), age, and gender each for 1.5 and 3.0 T field-strength scans of 342 patients. At both the field strengths, no significant differences in R2(*) of the cortex and medulla were found between patient gender, age, eGFR, or between different stages of chronic kidney disease determined using the KDOQI system. Thus, BOLD-MRI of a non-specific patient population failed to discriminate between the patients with various stages of chronic kidney disease.

DCE-MRI of the human kidney using BLADE: a feasibility study in healthy volunteers.

PURPOSE: To evaluate the degree of motion compensation in the kidney using two different sampling methods, each in their optimized settings: A BLADE k-space acquisition technique and a routinely used kidney perfusion acquisition scheme (TurboFLASH). MATERIALS AND METHODS: Dynamic contrast enhanced magnetic resonance examinations were performed in 16 healthy volunteers on a 3 Tesla MR-system with two parameterizations of the BLADE sequence and the standard reference acquisition scheme. Signal intensity enhanced time curves were analyzed with a mathematical model and a widely published separable compartment model on cortex regions to assess robustness versus motion artifacts. RESULTS: BLADE-measurements with a strip-width of 32 lines constituted the smallest mean values for the sum of squared errors (6065 ± 4996) compared with the measurement with a strip-width of 64 lines (13849 ± 14079) or the standard TurboFLASH (11884 ± 8076). Calculations concerning goodness of the fit of the applied compartment model yielded an overall average of the Akaike Fit Error of 732 ± 141 for BLADE (646 ± 149 for a strip-width of 32 lines, 816 ± 53 for 64 lines) and 1626 ± 303 for the TurboFLASH (TFL) sequence. CONCLUSION: We demonstrated that renal dynamic contrast enhanced magnetic resonance imaging using BLADE k-space sampling with a strip-width of 32 is significantly less sensitive to motion than a widely published Turbo-Flash sequence with nearly similar parameters.

Comparison of 0.5 M gadoterate and 1.0 M gadobutrol in peripheral MRA: a prospective, single-center, randomized, crossover, double-blind study.

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).