Non-contrast free-breathing 2D CINE compressed SENSE T1-TFE cardiovascular MRI at 3T in sedated young children for assessment of congenital heart disease.

Cardiac MRI is a crucial tool for assessing congenital heart disease (CHD). However, its application remains challenging in young children when performed at 3T. The aim of this retrospective single center study was to compare a non-contrast free-breathing 2D CINE T1-weighted TFE-sequence with compressed sensing (FB 2D CINE CS T1-TFE) with 3D imaging for diagnostic accuracy of CHD, image quality, and vessel diameter measurements in sedated young children. FB 2D CINE CS T1-TFE was compared with a 3D non-contrast whole-heart sequence (3D WH) and 3D contrast-enhanced MR angiography (3D CE-MRA) at 3T in 37 CHD patients (20♂, 1.5±1.4 years). Two radiologists independently assessed image quality, type of CHD, and diagnostic confidence. Diameters and measures of contrast and sharpness of the aorta and pulmonary vessels were determined. A non-parametric multi-factorial approach was used to estimate diagnostic accuracy for the diagnosis of CHD. Linear mixed models were calculated to compare contrast and vessel sharpness. Krippendorff's alpha was determined to quantify vessel diameter agreement. FB 2D CINE CS T1-TFE was rated superior regarding image quality, diagnostic confidence, and diagnostic sensitivity for both intra- and extracardiac pathologies compared to 3D WH and 3D CE-MRA (all p<0.05). FB 2D CINE CS T1-TFE showed superior contrast and vessel sharpness (p<0.001) resulting in the highest proportion of measurable vessels (740/740; 100%), compared to 3D WH (530/620; 85.5%) and 3D CE-MRA (540/560; 96.4%). Regarding vessel diameter measurements, FB 2D CINE CS T1-TFE revealed the closest inter-reader agreement (Krippendorff's alpha: 0.94-0.96; 3D WH: 0.78-0.94; 3D CE-MRA: 0.76-0.93). FB 2D CINE CS T1-TFE demonstrates robustness at 3T and delivers high-quality diagnostic results to assess CHD in sedated young children. Its ability to function without contrast injection and respiratory compensation enhances ease of use and could encourage widespread adoption in clinical practice.

Myocardial strain assessment in the human fetus by cardiac MRI using Doppler ultrasound gating and feature tracking.

OBJECTIVES: Assessment of myocardial strain by feature tracking magnetic resonance imaging (FT-MRI) in human fetuses with and without congenital heart disease (CHD) using cardiac Doppler ultrasound (DUS) gating. METHODS: A total of 43 human fetuses (gestational age 28-41 weeks) underwent dynamic cardiac MRI at 3 T. Cine balanced steady-state free-precession imaging was performed using fetal cardiac DUS gating. FT-MRI was analyzed using dedicated post-processing software. Endo- and epicardial contours were manually delineated from fetal cardiac 4-chamber views, followed by automated propagation to calculate global longitudinal strain (GLS) of the left (LV) and right ventricle (RV), LV radial strain, and LV strain rate. RESULTS: Strain assessment was successful in 38/43 fetuses (88%); 23 of them had postnatally confirmed diagnosis of CHD (e.g., coarctation, transposition of great arteries) and 15 were heart healthy. Five fetuses were excluded due to reduced image quality. In fetuses with CHD compared to healthy controls, median LV GLS (- 13.2% vs. - 18.9%; p < 0.007), RV GLS (- 7.9% vs. - 16.2%; p < 0.006), and LV strain rate (1.4 s-1 vs. 1.6 s-1; p < 0.003) were significantly higher (i.e., less negative). LV radial strain was without a statistically significant difference (20.7% vs. 22.6%; p = 0.1). Bivariate discriminant analysis for LV GLS and RV GLS revealed a sensitivity of 67% and specificity of 93% to differentiate between fetuses with CHD and healthy fetuses. CONCLUSION: Myocardial strain was successfully assessed in the human fetus, performing dynamic fetal cardiac MRI with DUS gating. Our study indicates that strain parameters may allow for differentiation between fetuses with and without CHD. CLINICAL RELEVANCE STATEMENT: Myocardial strain analysis by cardiac MRI with Doppler ultrasound gating and feature tracking may provide a new diagnostic approach for evaluation of fetal cardiac function in congenital heart disease. KEY POINTS: • MRI myocardial strain analysis has not been performed in human fetuses so far. • Myocardial strain was assessed in human fetuses using cardiac MRI with Doppler ultrasound gating. • MRI myocardial strain may provide a new diagnostic approach to evaluate fetal cardiac function.

Rapid MRI Assessment of Long-Axis Strain to Indicate Systolic Dysfunction in Patients With Sickle Cell Disease.

BACKGROUND: Patients with sickle cell disease (SCD) have a unique form of cardiomyopathy. However, left ventricular ejection fraction (LVEF) is often preserved. Monoplanar long-axis strain (LAS) can be assessed from MRI four-chamber views and may be better at detecting mild systolic dysfunction in these patients. PURPOSE: To compare LAS (monoplanar and biplanar) with LVEF as a marker of systolic dysfunction in SCD patients. STUDY TYPE: Retrospective. SUBJECTS: A total of 20 patients with genetically proven SCD (35 MRI examinations), 39 healthy controls, and 124 patients with systemic iron overload (for validation purposes). FIELD STRENGTH/SEQUENCE: 1.5 T/3 T. Cine balanced steady-state free-precession. ASSESSMENT: Rapidly assessed biplanar LAS from four- and two-chamber views was correlated with age and compared to LVEF by two operators. For validation, biplanar LAS was compared to global longitudinal strain (GLS) using MRI feature-tracking in 124 patients with systemic iron overload. STATISTICAL TESTS: Bland-Altman analysis. Wilcoxon-Mann-Whitney test and Spearman-rank correlation (correlation coefficient, rS ). Receiver-operating-characteristic (ROC) curve analysis (area under the curve, AUC). Bivariate discriminant analysis. Significance level: P < 0.01. RESULTS: There was strong correlation between biplanar LAS and GLS using feature tracking (rS  = 0.73). Interoperator agreement showed nonsignificant bias for biplanar LAS (-0.02%; ±95%-agreement interval -2.2%/2.2%, P = 0.9). Biplanar LAS increased significantly with age in controls (rS  = 0.70). In SCD patients, biplanar LAS was better correlated with age than monoplanar LAS (r2  = 0.53, standard error of estimate, SEE = 1.4% vs. r2  = 0.37;SEE = 2.0%). ROC analysis of LVEF, biplanar LAS, and age-adjusted Z-scores Z (LAS(age)) showed AUCs of 0.69, 0.75, and 0.86 for differentiation between SCD patients and controls. Bivariate discriminant analysis of biplanar Z (LAS(age)) and LVEF revealed a sensitivity of 63% and a specificity of 95%. DATA CONCLUSION: Rapidly assessed biplanar LAS demonstrated high diagnostic accuracy and was an indicator of mild systolic dysfunction in patients with SCD. Biplanar LAS provided more precise measurements than monoplanar, and normalization to age increased diagnostic accuracy. EVIDENCE LEVEL: 3. TECHNICAL EFFICACY: Stage 2.

Assessment of aortic diameter in Marfan patients: intraindividual comparison of 3D-Dixon and 2D-SSFP magnetic resonance imaging.

OBJECTIVES: To compare the accuracy and precision of 3D-Dixon and 2D-SSFP MR-imaging for assessment of aortic diameter in Marfan patients. METHODS: This prospective single-center study investigated respiratory-gated 3D-Dixon and breath-hold 2D-SSFP non-contrast MR-imaging at 3 T in 47 Marfan patients (36.0 ± 13.2 years, 28♀,19♂). Two radiologists performed individual diameter measurements at five levels of the thoracic aorta and evaluated image quality on a four-grade scale (1 = poor, 4 = excellent) and artifacts (1 = severe, 4 = none). Aortic root diameters acquired by echocardiography served as a reference standard. Intraclass correlation coefficient, Bland-Altman analyses, F-test, t-test, and regression analyses were used to assess agreement between observers and methods. RESULTS: Greatest aortic diameters were observed at the level of the sinuses of Valsalva (SOV) for 3D-Dixon (38.2 ± 6.8 mm) and 2D-SSFP (38.3 ± 7.1 mm) (p = 0.53). Intra- and interobserver correlation of diameter measurements was excellent at all aortic levels for both 3D-Dixon (r = 0.94-0.99 and r = 0.94-0.98) and 2D-SSFP (r = 0.96-1.00 and r = 0.95-0.99). 3D-Dixon-derived and 2D-SSFP-derived diameter measurements at the level of the SOV revealed a strong correlation with echocardiographic measurements (r = 0.92, p < 0.001 and r = 0.93, p < 0.001, respectively). The estimated mean image quality at the level of SOV was higher for 2D-SSFP compared to that for 3D-Dixon (3.3 (95%-CI: 3.1-3.5) vs. 2.9 (95%-CI: 2.7-3.1)) (p < 0.001). Imaging artifacts were less at all aortic levels for 3D-Dixon compared to 2D-SSFP (3.4-3.8 vs. 2.8-3.1) (all p < 0.002). CONCLUSION: Respiratory-gated 3D-Dixon and breath-hold 2D-SSFP MR-imaging provide accurate and precise aortic diameter measurements. We recommend 3D-Dixon imaging for monitoring of aortic diameter in Marfan patients due to fewer imaging artifacts and the possibility of orthogonal multiplanar reformations of the aortic root. KEY POINTS: • Respiratory-gated 3D-Dixon and breath-hold 2D-SSFP imaging provide accurate and precise aortic diameter measurements in patients suffering from Marfan syndrome. • Imaging artifacts are stronger in 2D-SFFP imaging than in 3D-Dixon imaging. • We recommend 3D-Dixon imaging for monitoring of aortic diameter in Marfan patients due to fewer imaging artifacts and the possibility of orthogonal multiplanar reformations.

Pre-interventional assessment of right renal to right adrenal vein distance: Impact on procedure time and radiation dose in adrenal vein sampling.

PURPOSE: Adrenal vein sampling (AVS) is the reference standard for evaluation of lateralized hormone production in primary aldosteronism. We aimed to investigate the impact of pre-interventional right renal vein (RRV) to right adrenal vein (RAV) distance measurement on fluoroscopy time, contrast agent exposure and radiation dose during AVS. MATERIALS AND METHODS: Forty-five patients with primary aldosteronism undergoing AVS were enrolled in our retrospective study and divided into three groups. In the group "ruler" (n = 14), RRV-RAV-distances were determined pre-interventionally by cross-sectional imaging (CT/MRI) and AVS was performed by one interventional radiologist with limited experience in AVS. CT/MRI-derived and fluoroscopy-derived RRV-RAV-distances were correlated for aimed cannulation of the RAV. Patients in group "no ruler" (n = 24, three interventional radiologists with limited experience in AVS) and in group "expert", (n = 7, one expert interventional radiologist) underwent AVS without pre-interventional estimation of RRV-RAV-distances. Procedure parameters (fluoroscopy time, contrast agent volume, radiation dose) of group "ruler" were compared to both other groups by Kruskal-Wallis rank-sum test. RESULTS: Correlation of CT/MRI-derived and fluoroscopy-derived RRV-RAV-distances was good (r = 0.74;p = 0.003). The median RRV-RAV-distance was 4.5cm at CT/MRI (95%-CI:4.2-5.0cm) and 4.0cm at fluoroscopy (95%-CI:3.8-4.5cm). Fluoroscopy time (p<0.0001), contrast agent exposure (p = 0.0003) and radiation dose (air kerma and dose area product both p = 0.038) were significantly lower in group "ruler" compared to group "no ruler" (all p<0.05), and similar to group "expert" (all p>0.05). CONCLUSIONS: CT/MRI-derived pre-interventional renal-adrenal vein distance measurements correlate well with angiographic distance measurements. Pre-interventional estimation of the RRV-RAV-distance allows for aimed cannulation of the RAV with potential reduction of fluoroscopy time, contrast agent exposure and radiation-dose during AVS.

Multi-organ assessment in mainly non-hospitalized individuals after SARS-CoV-2 infection: The Hamburg City Health Study COVID programme.

AIMS: Long-term sequelae may occur after SARS-CoV-2 infection. We comprehensively assessed organ-specific functions in individuals after mild to moderate SARS-CoV-2 infection compared with controls from the general population. METHODS AND RESULTS: Four hundred and forty-three mainly non-hospitalized individuals were examined in median 9.6 months after the first positive SARS-CoV-2 test and matched for age, sex, and education with 1328 controls from a population-based German cohort. We assessed pulmonary, cardiac, vascular, renal, and neurological status, as well as patient-related outcomes. Bodyplethysmography documented mildly lower total lung volume (regression coefficient -3.24, adjusted P = 0.014) and higher specific airway resistance (regression coefficient 8.11, adjusted P = 0.001) after SARS-CoV-2 infection. Cardiac assessment revealed slightly lower measures of left (regression coefficient for left ventricular ejection fraction on transthoracic echocardiography -0.93, adjusted P = 0.015) and right ventricular function and higher concentrations of cardiac biomarkers (factor 1.14 for high-sensitivity troponin, 1.41 for N-terminal pro-B-type natriuretic peptide, adjusted P ≤ 0.01) in post-SARS-CoV-2 patients compared with matched controls, but no significant differences in cardiac magnetic resonance imaging findings. Sonographically non-compressible femoral veins, suggesting deep vein thrombosis, were substantially more frequent after SARS-CoV-2 infection (odds ratio 2.68, adjusted P < 0.001). Glomerular filtration rate (regression coefficient -2.35, adjusted P = 0.019) was lower in post-SARS-CoV-2 cases. Relative brain volume, prevalence of cerebral microbleeds, and infarct residuals were similar, while the mean cortical thickness was higher in post-SARS-CoV-2 cases. Cognitive function was not impaired. Similarly, patient-related outcomes did not differ. CONCLUSION: Subjects who apparently recovered from mild to moderate SARS-CoV-2 infection show signs of subclinical multi-organ affection related to pulmonary, cardiac, thrombotic, and renal function without signs of structural brain damage, neurocognitive, or quality-of-life impairment. Respective screening may guide further patient management.

B-Flow Sonography vs. Color Doppler Sonography for the Assessment of Vascularity in Pediatric Kidney Transplantation.

OBJECTIVE: To compare B-flow sonography (BFS) with color Doppler sonography (CDS) for imaging of kidney transplant vascularization in children. PATIENTS AND METHODS: All children receiving a kidney transplantation who underwent a protocol-based ultrasound examination (Loqiq 9, GE Medical Systems, Milwaukee, WI, USA) using the BFS and CDS technique with equal settings and probe position between January 2013 and January 2016 were retrospectively assessed (n = 40). The obtained datasets were visually graded according to the following criteria: (I) delineation of the renal vascular tree (Grade 1 - clear demarcation of interlobar, together with arcuate and interlobular vessels; Grade 2 - clear demarcation of interlobar and cortical vessels, but no distinction of interlobular from arcuate vessels; Grade 3 - only clear demarcation of interlobar vessels, Grade 4 - insufficient demarcation) (II) delineation of cortical vessel density in ventral, lateral, and dorsal part of the transplant, (III) smallest vessel-capsule distance, and (IV) maximum cortical vessel count. Comparison between methods was performed using Fisher's exact and paired sample t-tests. RESULTS: Applying a curved transducer (C1-6), BFS showed superior delineation of the renal vascular tree (p < 0.001), a lower vessel-capsule distance (p < 0.001), a higher cortical vessel count (p < 0.001), and a higher cortical vessel density in the superficial cortex (p = 0.01) than CDS. In the dorsal and lateral aspects of the transplant, cortical vessel density was lower with BFS (both p < 0.001). Using a linear high-resolution transducer (ML 6-15), no significant differences between the methods were found. CONCLUSION: Improved imaging of kidney transplant vascularization can be achieved in children by adding BFS to a standard protocol. The BFS technique is especially beneficial for overall assessment of the renal vascular tree together with the extent of cortical vascularization on curved array images. KEY POINTS: · Depiction of vascular tree and ventral cortical vessels is improved by BFS.. · The dorso-lateral cortex was better represented with CDS because of higher penetration.. · Additional monitoring with BFS improves the monitoring of transplant viability.. CITATION FORMAT: · Dammann E, Groth M, Schild R et al. B-Flow Sonography vs. Color Doppler Sonography for the Assessment of Vascularity in Pediatric Kidney Transplantation. Fortschr Röntgenstr 2021; 193: 49 - 60.

Fetal dynamic magnetic resonance imaging using Doppler ultrasound gating for the assessment of the aortic isthmus: A feasibility study.

INTRODUCTION: Cardiovascular magnetic resonance imaging (MRI) is established in cardiac evaluation in postnatal life, but its application to the fetus has been hampered by technical limitations. We aimed to investigate the feasibility of dynamic MRI of the fetal aortic isthmus using a magnetic resonance-compatible Doppler ultrasound device for cardiac gating. MATERIAL AND METHODS: This prospective study included 19 fetuses at a median gestational age of 32.3 weeks (range 26-38 weeks). Imaging of the fetal aortic isthmus was assessed by (a) dynamic steady-state free precession MRI using a magnetic resonance-compatible Doppler ultrasound device for cardiac gating and (b) echocardiography. Diameters of the aortic isthmus were compared by two blinded observers. Magnetic resonance image quality was assessed independently by two observers using a four-point scale (1 = low quality, 4 = high quality). Furthermore, we performed four-dimensional flow MRI of the fetal aorta in three of these fetuses. RESULTS: The Doppler ultrasound device for cardiac gating allowed successful dynamic MRI examinations of the aortic isthmus in 18/19 (95%) fetuses. Evaluation of the fetal aortic isthmus was possible by both MRI (15/18, 83%) and echocardiography (16/18, 89%) (P < .05). Diameters of the aortic isthmus were concordant for MRI (3.8 ± 0.9 mm) and echocardiography (4.0 ± 1.1 mm), with a variability of 10.8% (bias -2.3%, 95% limits of agreement -23.9% to 19.3%). Overall magnetic resonance image quality was good (score 4 in 67% and score 3 in 23%) with good inter-observer agreement (κ = 0.75; 95% CI 0.5-1). Fetal four-dimensional flow MRI allowed visualization of aortic flow dynamics. CONCLUSIONS: Doppler ultrasound-gating allows dynamic MRI of the fetal aorta with the potential to serve as a complementary imaging tool in cases where echocardiography is inconclusive.

Objective assessment of patellar maltracking with 3 T dynamic magnetic resonance imaging: feasibility of a robust and reliable measuring technique.

Patellofemoral maltracking predisposes the patellofemoral joint to instability. The purpose of this study was to provide a reliable dynamic magnetic resonance imaging (MRI) measuring technique for patellofemoral maltracking, and to investigate the influence of anatomical risk factors (AF) on patellar maltracking. Ten patients (2 males,8 females, average 19 years) with clinical maltracking and 20 controls (10 males,10 females,average 28 years) were examined with a dynamic, multi-slice gradient-echo MRI sequence, during repetitive flexion(40°) and full extension, in an open-chain-active-movement. In a 30-s time frame three simultaneous transverse slices were acquired. Dynamic mediolateral translation and dynamic tilt were measured at defined positions, by two independent examiners. Reproducibility was tested in a set of five knees. Common AFs for patellar maltracking (tibial-tuberosity-to-trochlear-groove-(TT-TG)-distances, trochlea-sulcus-angle, trochlea-sulcus-depth, lateral-trochlear-inclination and Caton-Deschamps-Index) were analyzed in consensus, using standard static MRI sequences. In patients, dynamic mediolateral translation was significantly greater in patients (12.4 ± 6.9 mm vs. - 0.1 ± 2.3 mm, p < 0.001) and the patella was positioned significantly more laterally (17.5 ± 6.9 mm vs. 3.1 ± 2.4 mm, p < 0.001) compared to controls. During movement, the patella tilted 16.3 ± 13.1° laterally in patients and 1.9 ± 4.3° medially in controls (dynamic tilt) (p < 0.002). All AFs were significantly different between patients and controls. Pathological TT-TG-distances, Caton-Deschamps-Indices and trochlea-sulcus-angles strongly correlated with dynamic patellar translation and dynamic patellar tilt (p < 0.001). In the patient population, the primary pathologies for maltracking were lateralized-tibial-tubercle (n = 5), trochlea dysplasia n = 2, patella alta (n = 3). Interrater-reliability for translation and tilt-measurement was excellent (0.971/0.976, 95% CIs 0.939-0.986/0.950-0.988). Dynamic MRI reliably differentiates between abnormal and physiological patellar tracking. Dynamic tracking and tilt strongly correlate with measurable AFs, which reinforces their clinical use and validates the presented technique.

Comparative analysis of high field MRI and histology for ex vivo whole organ imaging: assessment of placental functional morphology in a murine model.

OBJECTIVES: The purpose of our study was to evaluate MRI as a tool to examine placental morphology in a murine model in comparison to classical histology techniques. METHODS: Assessment of placental samples (n = 24) from C57Bl/6 J mice was performed using MR imaging and histomorphological analyses. To optimize image contrast for MRI, a protocol for gadolinium-mediated enhancement of placental tissue was established. To test method sensitivity, placental zone assessment with MRI and histology was applied to a model of prenatal stress exposure known to affect placental morphology (n = 10). Mean data acquisition time for both methods was estimated. Difference between groups was calculated using the Mann-Whitney U test. RESULTS: Tissue fixation with formaldehyde and staining with gadolinium resulted in the best image quality. Placental functional zones were identified and measured with both MRI and histology. MRI and histology were able to detect changes in the L/Jz ratio upon a prenatal stress challenge (p = 0.001; p = 0.003). Data acquisition time was shorter using MRI assessment. CONCLUSIONS: Ex vivo MRI analyses of murine placental functional morphology with MRI are feasible and results are comparable to time-consuming histology. Both MRI and histology allow the detection of experimentally induced morphological tissue alterations.

Assessment of Congenital Vascular and Organ Anomalies in Subjects With Thalidomide Embryopathy Using Non-Contrast Magnetic Resonance Angiography.

BACKGROUND: To determine the type and frequency of vascular and organ malformations in adults with thalidomide embryopathy (TE) using non-contrast magnetic resonance angiography (MRA) and to assess the effect of the observed malformations on renal function. Methods and Results: The institutional ethics committee approved this prospective study and written informed consent was given by all 78 subjects (50 females) with TE (mean age: 55±1.1 years), who were examined by non-contrast MRA at 3T. ECG-triggered balanced turbo field echo images of the chest, abdomen and pelvis were obtained in coronal and sagittal orientations. Two observers assessed the frequency of vascular and organ malformations. Serum creatinine and estimated glomerular filtration rate (eGFR) were obtained to assess renal function. In 58 subjects, 99 vascular anomalies were observed, including 68 arterial (69%) and 31 venous anomalies (31%); 15 patients had 16 abdominal organ malformations including 12 kidney anomalies and 4 cases of gallbladder agenesis. Most vascular anomalies affected the renal vessels (n=66, 67%) or supraaortic arteries (n=28, 28%). Serum creatinine and eGFR revealed normal renal function in all subjects. CONCLUSIONS: Vascular and organ anomalies occurred in a high number of subjects with TE without evidence of renal dysfunction. Information about the presence of malformations may be important for future surgical interventions in subjects with TE.

Low-Dose CT for Evaluation of Suspected Urolithiasis: Diagnostic Yield for Assessment of Alternative Diagnoses.

OBJECTIVE: The purpose of this study is to assess the diagnostic yield of low-dose (LD) CT for alternative diagnoses in patients with suspected urolithiasis. MATERIALS AND METHODS: In this retrospective study, we included 776 consecutive patients who underwent unenhanced abdominal CT for evaluation of suspected urolithiasis. All examinations were performed with an LD CT protocol; images were reconstructed using iterative reconstruction. The leading LD CT diagnosis was recorded for each patient and compared with the final clinical diagnosis, which served as the reference standard. RESULTS: The mean (± SD) effective dose of CT was 1.9 ± 0.6 mSv. The frequency of urolithiasis was 82.5% (640/776). LD CT reached a sensitivity of 94.1% (602/640), a specificity of 100.0% (136/136), and an accuracy of 95.1% (738/776) for the detection of urolithiasis. In 93 of 136 patients (68.4%) without urolithiasis, alternative diagnoses were established as the final clinical diagnoses. Alternative diagnoses were most commonly located in the genitourinary (n = 53) and gastrointestinal (n = 18) tracts. LD CT correctly provided alternative diagnoses for 57 patients (61.3%) and was false-negative for five patients (5.4%). The most common clinical alternative diagnoses were urinary tract infections (n = 22). Seven diagnoses missed at LD CT were located outside the FOV. For 43 of all 776 patients (5.5%), neither LD CT nor clinical workup could establish a final diagnosis. The sensitivity, specificity, and accuracy of LD CT for the detection of alternative diagnoses were 91.9% (57/62), 95.6% (43/45), and 93.5% (100/107), respectively. CONCLUSION: LD CT enables the diagnosis of most alternative diagnoses in the setting of suspected urolithiasis. The most frequent alternative diagnoses missed by LD CT are urinary tract infections or diagnoses located outside the FOV of the abdominopelvic CT scan.

Accuracy of multiparametric MR imaging with PI-RADS V2 assessment in detecting infiltration of the neurovascular bundles prior to prostatectomy.

OBJECTIVES: To evaluate the accuracy of assessment of neurovascular bundle (NVB) infiltration using multiparametric magnetic resonance imaging (mpMRI) and PI-RADS V2 prior to prostatectomy. METHODS: The ethics committee approved this retrospective study with waiver of informed consent. N=198 consecutive patients with biopsy proved cancer underwent standardized mpMRI at 3T prior to surgery. NVB infiltration was assessed for each side (a total of 396). Maximum PI-RADS V2 scores were determined for the posterolateral areas adjacent to the NVBs. Imaging results were correlated with postoperative pathology and standard descriptive statistics were calculated. RESULTS: Overall T-staging sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy of mpMRI were 64.4%, 89.2%, 82.4%, 76.2% and 78.3%, respectively. In 396 cases NVB infiltration was predicted with 75.3%, 94.0%, 80.2%, 92.1 % and 89.4 % sensitivity, specificity, PPV, NPV and accuracy, respectively. Analyses of 396 NVB and their adjacent PI-RADS V2 scores with pathology revealed significantly more NVB-infiltrations in suspect scores of 5 and 4 vs. uncertain scores of 3-1 (81/264 vs. 16/132, p=0.0001). Considering scores higher than 3 as a criterion of infiltration demonstrated moderate sensitivity and poor specificity (83.5% and 38.8%, respectively). Interobserver agreement of a second reading of a random sample was good (κ=0.64) for NVB infiltrations and moderate (κ=0.59) for PI-RADS V2. CONCLUSIONS: Assessment of infiltration of the neurovascular bundles using mpMRI has valuable diagnostic performance, yet PI-RADS V2 Scores demonstrate limited eligibility. Combined findings offer crucial information for the planning of prostatectomy.

Acute versus Chronic Myocardial Infarction: Diagnostic Accuracy of Quantitative Native T1 and T2 Mapping versus Assessment of Edema on Standard T2-weighted Cardiovascular MR Images for Differentiation.

Purpose To analyze the diagnostic accuracy of native T1 and T2 mapping compared with visual and quantitative assessment of edema on T2-weighted cardiac magnetic resonance (MR) images to differentiate between acute and chronic myocardial infarction. Materials and Methods This study had institutional ethics committee approval. Written informed consent was obtained from 67 consecutive patients (57 years ± 12; 78% men) with a first acute myocardial infarction, who were prospectively enrolled between April 2011 and June 2015. Four serial 1.5-T MR imaging examinations were performed at 8 days ± 5, 7 weeks ± 2, 3 months ± 0.5, and 6 months ± 1.4 after infarction and included T2-weighted, native T1/T2 mapping, and late gadolinium enhancement MR imaging. Complete follow-up data were obtained in 42 patients. Regional native T1/T2 relaxation time, T2-weighted ratio, and extracellular volume were serially measured in infarcted and remote myocardium. Receiver operating characteristic (ROC) analysis was used to determine the diagnostic accuracy of the MR imaging parameters for discriminating between acute and chronic myocardial infarction. Results Native T1 of infarcted myocardium decreased from 1286 msec ± 99 at baseline to 1077 msec ± 50 at 6 months (P < .0001), whereas T2 decreased from 84 msec ± 10 to 58 msec ± 4 (P < .0001). The T2-weighted ratio decreased from 4.1 ± 1.0 to 2.4 ± 0.6 (P < .0001). Of all the MR imaging parameters obtained, native T1 and T2 yielded the best areas under the ROC curve (AUCs) of 0.975 and 0.979, respectively, for differentiating between acute and chronic myocardial infarction. Visual analysis of the presence of edema at standard T2-weighted cardiac MR imaging resulted in an inferior AUC of 0.863 (P < .01). Conclusion Native T1 and T2 of infarcted myocardium are excellent discriminators between acute and chronic myocardial infarction and are superior to all other MR imaging parameters. Online supplemental material is available for this article.

Functional assessment of the kidneys in a 10 month-old child with renal artery stenosis by intravoxel incoherent motion.

Renovascular stenosis is an important cause for arterial hypertension in childhood. We report a 10-month-old girl with arterial hypertension caused by right-sided renal artery stenosis detected by Doppler ultrasound. Magnetic resonance imaging (MRI) was performed before renal artery angioplasty to depict vascular anatomy in detail and to retrieve additional functional information of the kidneys by analysis of intravoxel incoherent motion (IVIM). The value of quantitative diffusion weighted imaging of the kidneys prior to percutaneous transluminal renal angioplasty (PTRA) is discussed.

MDCT of acute pancreatitis: Intraindividual comparison of single-phase versus dual-phase MDCT for initial assessment of acute pancreatitis using different CT scoring systems.

OBJECTIVES: The purpose of the retrospective study was to evaluate the additional value of dual-phase multidetector computed tomography (MDCT) protocols over a single-phase protocol on initial MDCT in patients with acute pancreatitis using three CT-based pancreatitis severity scores with regard to radiation dose. METHODS: In this retrospective, IRB approved study MDCT was performed in 102 consecutive patients (73 males; 55years, IQR48-64) with acute pancreatitis. Inclusion criteria were CT findings of interstitial edematous pancreatitis (IP) or necrotizing pancreatitis (NP) and a contrast-enhanced dual-phase (arterial phase and portal-venous phase) abdominal CT performed at ≥72h after onset of symptoms. The severity of pancreatic and extrapancreatic changes was independently assessed by 2 observers using 3 validated CT-based scoring systems (CTSI, mCTSI, EPIC). All scores were applied to arterial phase and portal venous phase scans and compared to score results of portal venous phase scans, assessed ≥14days after initial evaluation. For effective dose estimation, volume CT dose index (CTDIvol) and dose length product (DLP) were recorded in all examinations. RESULTS: In neither of the CT severity scores a significant difference was observed after application of a dual-phase protocol compared with a single-phase protocol (IP: CTSI: 2.7 vs. 2.5, p=0.25; mCTSI: 4.0 vs. 4.0, p=0.10; EPIC: 2.0 vs. 2.0, p=0.41; NP: CTSI: 8.0 vs. 7.0, p=0.64; mCTSI: 8.0 vs. 8.0, p=0.10; EPIC: 3.0 vs. 3.0, p=0.06). The application of a single-phase CT protocol was associated with a median effective dose reduction of 36% (mean dose reduction 31%) compared to a dual-phase CT scan. CONCLUSIONS: An initial dual-phase abdominal CT after ≥72h after onset of symptoms of acute pancreatitis was not superior to a single-phase protocol for evaluation of the severity of pancreatic and extrapancreatic changes. However, the effective radiation dose may be reduced by 36% using a single-phase protocol.

Nerve Sheath Tumors in Neurofibromatosis Type 1: Assessment of Whole-Body Metabolic Tumor Burden Using F-18-FDG PET/CT.

PURPOSE: To determine the metabolically active whole-body tumor volume (WB-MTV) on F-18-fluorodeoxyglucose positron emission tomography/computed tomography (F-18-FDG PET/CT) in individuals with neurofibromatosis type 1 (NF1) using a three-dimensional (3D) segmentation and computerized volumetry technique, and to compare PET WB-MTV between patients with benign and malignant peripheral nerve sheath tumors (PNSTs). PATIENTS AND METHODS: Thirty-six NF1 patients (18 patients with malignant PNSTs and 18 age- and sex-matched controls with benign PNSTs) were examined by F-18-FDG PET/CT. WB-MTV, whole-body total lesion glycolysis (WB-TLG) and a set of semi-quantitative imaging-based parameters were analyzed both on a per-patient and a per-lesion basis. RESULTS: On a per-lesion basis, malignant PNSTs demonstrated both a significantly higher MTV and TLG than benign PNSTs (p < 0.0001). On a per-patient basis, WB-MTV and WB-TLG were significantly higher in patients with malignant PNSTs compared to patients with benign PNSTs (p < 0.001). ROC analysis showed that MTV and TLG could be used to differentiate between benign and malignant tumors. CONCLUSIONS: WB-MTV and WB-TLG may identify malignant change and may have the potential to provide a basis for investigating molecular biomarkers that correlate with metabolically active disease manifestations. Further evaluation will determine the potential clinical impact of these PET-based parameters in NF1.

Magnetic resonance enterography for assessment of intestinal graft-versus-host disease after allogeneic stem cell transplantation.

OBJECTIVES: To determine the diagnostic performance of MR enterography (MRE) for detection and grading of gastrointestinal graft-versus-host disease (GI GvHD) after hematopoietic stem cell transplantation (SCT). METHODS: Forty-one patients with known GvHD or suspected GvHD underwent MRE and GI endoscopy with multi-level biopsies. MRE images were reviewed for presence of intestinal wall inflammation. Clinical grading of GI GvHD was performed. Histopathological evaluation (HPE) served as the reference standard. RESULTS: Overall, MRE demonstrated a per-patient sensitivity of 81.5 % for detection of GI GvHD. The most common findings were intestinal wall thickening (81.5 % of GvHD patients), luminal stenosis (81.5 %), mural contrast enhancement (70.4 %), and ascites (59.3 %). These findings were also observed in other conditions than GvHD. The most frequently involved intestinal segment was the sigmoid colon (63.0 %), followed by the ileum (59.3 %) and the jejeunum (51.9 %). The number of involved segments (r s =0.54, p =0.009) correlated significantly with clinical severity as determined by GvHD grading. CONCLUSIONS: After allogeneic stem cell transplantation, MRE may (1) contribute to detection and localization of GI GvHD, and (2) add information indicating the clinical severity of disease, but findings are unspecific. False negative results may be observed not only in low-grade GI GvHD. KEY POINTS: • Magnetic resonance enterography (MRE) allows for detection of GI GvHD • Common findings are wall thickening, stenosis, mural contrast enhancement, and ascites • The extent of GI involvement on MRE correlates with clinical severity of GvHD • Involvement of sigmoid colon and small intestine is common • Findings are unspecific and also observed in other conditions, e.g. infectious enteritis.

Pancreatic iron and fat assessment by MRI-R2* in patients with iron overload diseases.

BACKGROUND: To determine the pancreatic iron (R2*) and fat content (FC) in comparison to hepatic and cardiac R2* in patients with iron overload disorders like ß-thalassemia major (TM), Diamond-Blackfan anemia (DBA) or hereditary hemochromatosis. METHODS: R2* rates were assessed in the liver, heart and pancreas of 42 patients with TM, 29 subjects with other iron overload diseases, and 10 controls using an ECG-gated breathhold sequence (12 echo time [TE] = 1.3-25.7 ms, readout repetition time [TR] = 244 ms). Pancreatic R2* and FC were assessed from TE dependent region of interest based signal intensities performing water-fat chemical shift relaxometry and were compared with laboratory parameters (glucose, HbA1c, amylase and lipase). RESULTS: A pancreatic iron gradient from tail (R2* = 122 s(-1) ) to head (R2* = 114 s(-1) , P < 10(-4) ) was found. The close association between cardiac and pancreatic R2* was also confirmed in patients with TM and other iron overload diseases (rs = 0.64, P < 10(-4) ). Receiver operator characteristic analysis (area: 0.89, P < 10(-4) ) identified patients with elevated cardiac iron at a pancreatic R2* cut-off level of 131s(-1) (sensitivity = specificity at 81%). Highest pancreatic R2* (211s(-1) ) and FC (36%) were found in the tail region of diabetic patients with TM. CONCLUSION: Pancreatic tail showed highest R2* rates and fat contents, especially in patients with thalassemia. Besides iron accumulation fatty degeneration might be an additional risk factor for the development of diabetes in ß-thalassemia major, but this hypothesis needs further studies in prediabetic patients.

Quantification of prenatal liver and spleen iron in a sheep model and assessment of iron stores in a human neonate with neonatal hemochromatosis using R2* mapping.

PURPOSE: We evaluated the feasibility of prenatal quantification of liver and spleen iron by magnetic resonance imaging (MRI) gradient recalled echo (GRE) measurements of transverse relaxation time (R2*) (MRI-GRE-R2*) in a fetal sheep model and applied the method to a human neonate with suspected neonatal hemochromatosis. METHODS: We subjected 13 fetal sheep to MRI at 1.5 Tesla using a breath-triggered (ewe) multi-echo sequence to determine the transverse relaxation rate (R2*) of the liver and spleen. In the human neonate, we measured the R2* of the liver, spleen, and pancreas on the 30th postgestational day. RESULTS: The median R2* of the fetal sheep liver was 25.6 s(-1) (range 20 to 114 s(-1)) and of the spleen, 40.2 s(-1) (range 20 to 70 s(-1)), and the corresponding median iron concentration in the liver was 0.85 mg/g dry weight (d.w.) and in the spleen, 1.22 mg/gd.w.. R2* rates in the human neonate liver were elevated between 67 s(-1) (average), which corresponded with an iron concentration of 1.9 mg Fe/gd.w., and 126 s(-1) (regional maximum), which corresponded with 3.4 mg Fe/gd.w.. The average pancreatic R2* (72.4 s(-1)) was significantly above normal values, which indicated iron overload. CONCLUSION: We demonstrated the feasibility of prenatal quantification of tissue iron by fetal MRI in this sheep model and successfully quantified iron, including that in the pancreas, in a human neonate to confirm the diagnosis of neonatal hemochromatosis. Transferring the successful approach of quantifying iron in intrauterine tissue in fetal sheep to human pregnancies with suspected fetal siderosis could aid early diagnosis.