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.

Genotype-phenotype correlation in neurofibromatosis type-1: NF1 whole gene deletions lead to high tumor-burden and increased tumor-growth.

Neurofibromatosis type-1 (NF1) patients suffer from cutaneous and subcutaneous neurofibromas (CNF) and large plexiform neurofibromas (PNF). Whole gene deletions of the NF1 gene can cause a more severe phenotype compared to smaller intragenic changes. Two distinct groups of NF1 whole gene deletions are type-1 deletions and atypical deletions. Our aim was to assess volumes and averaged annual growth-rates of CNF and PNF in patients with NF1 whole gene deletions and to compare these with NF1 patients without large deletions of the NF1 gene. We retrospectively evaluated 140 whole-body MR examinations of 38 patients with NF1 whole gene deletions (type-1 group: n = 27/atypical group n = 11) and an age- and sex matched collective of 38 NF1-patients. Age-dependent subgroups were created (0-18 vs >18 years). Sixty-four patients received follow-up MRI examinations (NF1whole gene deletion n = 32/control group n = 32). Whole-body tumor-volumes were semi-automatically assessed (MedX, V3.42). Tumor volumes and averaged annual growth-rates were compared. Median tumor-burden was significantly higher in the type-1 group (418ml; IQR 77 - 950ml, p = 0.012) but not in the atypical group (356ml;IQR 140-1190ml, p = 0.099) when compared to the controls (49ml; IQR 11-691ml). Averaged annual growth rates were significantly higher in both the type-1 group (14%/year; IQR 45-36%/year, p = 0.004) and atypical group (11%/year; IQR 5-23%/year, p = 0.014) compared to the controls (4%/year; IQR1-8%/year). Averaged annual growth rates were significantly higher in pediatric patients with type-1 deletions (21%/year) compared with adult patients (8%/year, p = 0.014) and also compared with pediatric patients without large deletions of the NF1 gene (3.3%/year, p = 0.0015). NF1 whole gene deletions cause a more severe phenotype of NF1 with higher tumor burden and higher growth-rates compared to NF1 patients without large deletions of the NF1 gene. In particular, pediatric patients with type-1 deletions display a pronounced tumor growth.

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.

Longitudinal follow-up by MR angiography reveals progressive dilatation of the distal aorta after aortic root replacement in Marfan syndrome.

OBJECTIVES: To define and compare growth rates of the distal aorta in Marfan patients with and without aortic root replacement using serial MR angiography (MRA). METHODS: We retrospectively included 136 Marfan patients with a total of 645 MRAs who underwent a median of five MRAs (range: 2-13) at 1.5 T and 3 T in annual intervals. Of these, 41 patients (34.8 ± 12 years) had undergone aortic root replacement. The remaining 95 patients (29.0 ± 17 years) still had a native aorta and served as the control group. Thoracic aortic diameters were independently measured at eleven predefined levels. Estimated growth rates were calculated using a mixed effects model adjusted for sex, age, BMI, and medication. RESULTS: Marfan patients with aortic root replacement revealed the highest mean estimated growth rate in the proximal descending aorta (0.77 mm/year, CI: 0.31-1.21). Mean growth rates at all levels of the distal thoracic aorta were significantly higher in patients with aortic root replacement (0.28-0.77 mm/year) when compared to patients without aortic root replacement (0.03-0.07 mm/year) (all p < 0.001). Antihypertensive medication, gender, and BMI had no significant impact on the distal aortic growth rates. CONCLUSION: Distal thoracic aortic diameters increase at a significantly higher rate in Marfan patients with aortic root replacement compared to Marfan patients without aortic root replacement. Further studies are warranted to investigate if the increased growth rate of the distal thoracic aorta after aortic root replacement is caused by altered hemodynamics due to the rigid aortic root graft or due to the general genetic disposition of post-operative Marfan patients. CLINICAL RELEVANCE STATEMENT: High growth rates of the distal aorta after aortic root replacement underline the need for careful life-long aortic imaging of Marfan patients after aortic root replacement. KEY POINTS: • Aortic growth rates in Marfan patients with aortic root replacement are highest in the mid-aortic arch, the proximal- and mid-descending aorta. • Growth rates of the distal thoracic aorta are significantly higher in Marfan patients with aortic root replacement compared to Marfan patients without aortic root replacement. • Antihypertensive medication, gender, and BMI have no significant impact on distal aortic growth rates in Marfan patients.

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.

Validation of 4D flow cardiovascular magnetic resonance in TIPS stent grafts using a 3D-printed flow phantom.

BACKGROUND: Four-dimensional (4D) flow cardiovascular magnetic resonance (CMR) is feasible for portal blood flow evaluation after placement of transjugular intrahepatic portosystemic shunts (TIPS) in patients with liver cirrhosis. However, clinical acceptance of 4D flow CMR in TIPS patients is limited due to the lack of validation studies. The purpose of this study was to validate 4D flow CMR-derived measurements in TIPS stent grafts using a three-dimensional (3D)-printed flow phantom. METHODS: A translucent flow phantom of the portal vasculature was 3D-printed. The phantom consisted of the superior mesenteric vein and the splenic vein draining into the portal vein, the TIPS-tract, and the hepatic vein. A TIPS stent graft (Gore® Viatorr®) was positioned within the TIPS-tract. Superior mesenteric vein and splenic vein served as inlets for blood-mimicking fluid. 4D flow CMR acquisitions were performed at 3T at preset flow rates of 0.8 to 2.8 l/min using velocity encoding of both 1.0 and 2.0 m/s. Flow rates and velocities were measured at predefined levels in the portal vasculature and within the stent graft. Accuracy of 4D flow CMR was assessed through linear regression with reference measurements obtained by flow sensors and two-dimensional (2D) phase contrast (PC) CMR. Intra- and interobserver agreement were assessed through Bland-Altman analyses. RESULTS: At a velocity encoding of 2.0 m/s, 4D flow CMR-derived flow rates and velocities showed an excellent correlation with preset flow rates and 2D PC CMR-derived flow velocities at all vascular levels and within the stent graft (all r ≥ 0.958, p ≤ 0.003). At a velocity encoding of 1.0 m/s, aliasing artifacts were present within the stent graft at flow rates ≥ 2.0 l/min. 4D flow CMR-derived measurements revealed high intra- and interobserver agreement. CONCLUSIONS: The in vitro accuracy and precision of 4D flow CMR is unaffected by the presence of TIPS stent grafts, suggesting that 4D flow CMR may be used to monitor TIPS patency in patients with liver cirrhosis.

Can homogeneous, lipomatous tumors be primarily resected without biopsy? A retrospective analysis of 240 tumors.

BACKGROUND: According to guidelines, every soft tissue tumor (STT) larger than 3 cm should be biopsied before definitive resection. Advances in magnetic resonance imaging (MRI) improve the possibility to give a provisional diagnosis of the tumor's entity. Can lipomas and atypical lipomatous tumors (ALTs) of the extremities therefore be primarily marginally resected based on interpretation of MR images without a previous biopsy?. METHODS: In this retrospective, single-center study, 240 patients with the suspicion of a lipomatous tumor in MRI and surgical treatment in our institution between 2011 and 2020 were included. MR imaging was performed before surgery. All resected specimens underwent histopathological analysis. RESULTS: The collective comprised 142 tumors that were suspected as lipoma or ALT by the radiologist and underwent primary marginal resection (PMR). One case had myxoid liposarcoma that was underestimated on MRI and needed radical follow-up resection. One-hundred forty-one patients were cured after PMR. Ninety-eight patients were biopsied initially and in 93 cases resected afterwards according to the necessary oncological margins. CONCLUSION: In our institution, PMR is performed if a lipoma or ALT is suspected on MR imaging. Our treatment method and the diagnostic algorithm are presented. Primary resection spares patients from one surgical procedure, but a slight risk for underestimation of the tumor remains.

Impact of chest wall deformity on cardiac function by CMR and feature-tracking strain analysis in paediatric patients with Marfan syndrome.

OBJECTIVES: To evaluate systolic cardiac dysfunction in paediatric MFS patients with chest wall deformity using cardiac magnetic resonance (CMR) imaging and feature-tracking strain analysis. METHODS: Forty paediatric MFS patients (16 ± 3 years, range 8-22 years) and 20 age-matched healthy controls (16 ± 4 years, range 11-24 years) were evaluated retrospectively. Biventricular function and volumes were determined using cine sequences. Feature-tracking CMR was used to assess global systolic longitudinal (GLS), circumferential (GCS) and radial strain (GRS). A dedicated balanced turbo field echo sequence was used to quantify chest wall deformity by measuring the Haller index (HI). RESULTS: LV volumes and ejection fraction (EF) were similar in MFS patients and controls. There was a trend for lower right ventricular (RV) volume (75 ± 17 vs. 81 ± 10 ml/m2, p = 0.08), RV stroke volume (41 ± 12 vs. 50 ± 5 ml/m2, p < 0.001) and RVEF (55 ± 10 vs. 62 ± 6%, p < 0.01) in MFS patients. A subgroup of MFS patients had an increased HI compared to controls (4.6 ± 1.7 vs. 2.6 ± 0.3, p < 0.001). They demonstrated a reduced RVEF compared to MFS patients without chest wall deformity (50 ± 11% vs. 58 ± 8%, p = 0.01) and controls (p < 0.001). LV GLS was attenuated when HI ≥ 3.25 (- 16 ± 2 vs. - 18 ± 3%, p = 0.03), but not GCS and GRS. LV GLS (p < 0.01) and GCS (p < 0.0001) were attenuated in MFS patients compared to controls, but not GRS (p = 0.31). RV GLS was attenuated in MFS patients compared to controls (- 21 ± 3 vs. - 23 ± 3%, p < 0.05). CONCLUSION: Chest wall deformity in paediatric MFS patients is associated with reduced RV volume, ejection fraction and GLS. Feature-tracking CMR also indicates impairment of systolic LV function in paediatric MFS patients. KEY POINTS: • Paediatric Marfan patients demonstrate reduced RV volume and ejection fraction compared to healthy controls. • A concordant attenuation in RV global longitudinal strain was observed in Marfan patients, while the RV global circumferential strain was increased, indicating a possible compensatory mechanism. • Subgroup analyses demonstrated alterations in RV ejection fraction and RV/LV global strain parameters, indicating a possible association of severe chest wall deformity with biventricular dysfunction in paediatric Marfan patients.

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.

4D flow cardiovascular magnetic resonance for monitoring of aortic valve repair in bicuspid aortic valve disease.

BACKGROUND: Aortic valve repair has become a treatment option for adults with symptomatic bicuspid (BAV) or unicuspid (UAV) aortic valve insufficiency. Our aim was to demonstrate the feasibility of 4D flow cardiovascular magnetic resonance (CMR) to assess the impact of aortic valve repair on changes in blood flow dynamics in patients with symptomatic BAV or UAV. METHODS: Twenty patients with adult congenital heart disease (median 35 years, range 18-64; 16 male) and symptomatic aortic valve regurgitation (15 BAV, 5 UAV) were prospectively studied. All patients underwent 4D flow CMR before and after aortic valve repair. Aortic valve regurgitant fraction and systolic peak velocity were estimated. The degree of helical and vortical flow was evaluated according to a 3-point scale. Relative flow displacement and wall shear stress (WSS) were quantified at predefined levels in the thoracic aorta. RESULTS: All patients underwent successful aortic valve repair with a significant reduction of aortic valve regurgitation (16.7 ± 9.8% to 6.4 ± 4.4%, p < 0.001) and systolic peak velocity (2.3 ± 0.9 to 1.9 ± 0.4 m/s, p = 0.014). Both helical flow (1.6 ± 0.6 vs. 0.9 ± 0.5, p < 0.001) and vortical flow (1.2 ± 0.8 vs. 0.5 ± 0.6, p = 0.002) as well as both flow displacement (0.3 ± 0.1 vs. 0.25 ± 0.1, p = 0.031) and WSS (0.8 ± 0.2 N/m2 vs. 0.5 ± 0.2 N/m2, p < 0.001) in the ascending aorta were significantly reduced after aortic valve repair. CONCLUSIONS: 4D flow CMR allows assessment of the impact of aortic valve repair on changes in blood flow dynamics in patients with bicuspid aortic valve disease.

MDCT in the Setting of Suspected Colonic Diverticulitis: Prevalence and Diagnostic Yield for Diverticulitis and Alternative Diagnoses.

OBJECTIVE. The purpose of this study was to determine the prevalence and demographic distribution of colonic diverticulitis (CD) and alternative diagnoses (AD), as well as the diagnostic accuracy of MDCT in patients with suspected CD. MATERIALS AND METHODS. This study retrospectively included 1069 patients (560 women) undergoing MDCT for the evaluation of suspected CD. The prevalence of CD and AD was determined and the diagnostic accuracy of MDCT calculated. The final clinical diagnosis derived from the discharge report served as the standard of reference. Prevalence of diagnoses by age, sex, and admission status were compared using Cochran-Armitage, chi-square, and Fisher exact tests. RESULTS. Prevalence of CD was 52.5% (561/1069) and of AD was 39.9% (427/1069). In the remaining 7.6% (81/1069) no final clinical diagnosis was established. The most frequent AD were appendicitis (12.6%, 54/427), infectious colitis (10.5%, 45/427), infectious gastroenteritis (8.2%, 35/427), urolithiasis (6.1%, 26/427), and pyelonephritis (4.9%, 21/427). The prevalence of diverticulitis and AD varied statistically significantly according to both age (p < 0.001) and admission status (p < 0.001). Also, the prevalence of the 10 most frequent specific AD varied statistically significantly according to sex (p = 0.022). CT had a sensitivity and specificity of 99.1% and 99.8% for diagnosing CD and 92.7% and 98.8% for AD, respectively. CONCLUSION. In about 40% of patients with suspected diverticulitis a broad spectrum of AD is causative for symptoms. MDCT provides high diagnostic accuracy in the diagnosis of diverticulitis and AD. The prevalence of diagnoses is related to admission status and demographic data; in particular age-related AD have to be considered in patients with clinically suspected diverticulitis.

Implementation of a 24-Hour Teleradiology Service for Cruise Ships: A Pilot Study.

OBJECTIVE. The purpose of this study was to introduce a 24-hour teleradiology service for cruise ships as a novel concept in maritime telemedicine. SUBJECTS AND METHODS. One cruise ship equipped with a mobile radiography unit and digital storage imaging plates was involved in this pilot study. Radiographs were transmitted via satellite internet to a tertiary hospital on shore for image interpretation by expert radiologists. Use of a virtual private network (VPN) enabled secure data transfer. Radiographs and patient data were automatically integrated into the PACS and radiology information system of the radiology department at the hospital. Images were analyzed by the staff radiologist at the hospital, and reports were immediately returned via e-mail through the VPN tunnel. RESULTS. Seventy-five radiographs of 47 patients were obtained on board within 2 months. All datasets were successfully transmitted. Most of the examinations (35 [≈ 75%]) were skeletal radiographs; the other 12 (≈ 25%) were chest radiographs. The turnaround time for the radiology reports was within 30 minutes in 43 cases (≈ 92%). In four cases (≈ 8%), delay was due to technical and organizational issues at the tertiary hospital. CONCLUSION. With the objective of supporting ship physicians with expert analyses of radiographs, a secure and stable method of image and radiology report transmission between an onboard hospital and a land-based radiology department was established.

Four-dimensional Flow MRI as a Marker for Risk Stratification of Gastroesophageal Varices in Patients with Liver Cirrhosis.

Purpose To assess the feasibility of four-dimensional (4D) flow MRI as a noninvasive imaging marker for stratifying the risk of variceal bleeding in patients with liver cirrhosis. Materials and Methods This study recruited participants scheduled for both liver MRI and gastroesophageal endoscopy. Risk of variceal bleeding was assessed at endoscopy by using a three-point scale: no varices, low risk, and high risk requiring treatment. Four-dimensional flow MRI was used to create angiograms for evaluating visibility of varices and to measure flow volumes in main portal vein (PV), superior mesenteric vein, splenic vein (SV), and azygos vein. Fractional flow changes in PV and SV were calculated to quantify shunting (outflow) from PV and SV into varices. Logistic analysis was used to identify the independent indicator of high-risk varices. Results There were 23 participants (mean age, 52.3 years; age range, 25-75 years), including 14 men (mean age, 51.7 years; age range, 25-75 years) and nine women (mean age, 53.2 years; age range, 31-72 years) with no varices (n = 8), low-risk varices (n = 8), and high-risk varices (n = 7) determined at endoscopy. Four-dimensional flow MRI-based angiography helped radiologists to view varices in four of 15 participants with varices. Independent indicators of high-risk varices were flow volume in the azygos vein greater than 0.1 L/min (P = .034; 100% sensitivity [seven of seven] and 62% specificity [10 of 16]) and fractional flow change in PV of less than 0 (P < .001; 100% sensitivity [seven of seven] and 94% specificity [15 of 16]). Conclusion Azygos flow greater than 0.1 L/min and portal venous flow less than the sum of splenic and superior mesenteric vein flow are useful markers to stratify the risk of gastroesophageal varices bleeding in patients with liver cirrhosis. © RSNA, 2018 Online supplemental material is available for this article.

The impact of [68Ga]PSMA I&T PET/CT on radiotherapy planning in patients with prostate cancer.

PURPOSE: To determine the impact of Gallium-68-labled prostate-specific membrane antigen positron-emission tomography/computed tomography ([68Ga]PSMA PET/CT) on radiotherapy planning for primary disease, biochemical cancer relapse, and advanced disease of prostate cancer. METHODS: A total of 106 patients with prostate cancer scheduled for radiation therapy underwent 120 [68Ga]PSMA PET/CT scans prior to radiotherapy treatment. In 20 cases, patients underwent [68Ga]PSMA PET/CT for primary therapy (PT), 75 cases were referred for biochemical relapse after surgery (RL), and 25 cases were intended for palliative treatment of localized metastases (MD). We retrospectively compared the impact of [68Ga]PSMA PET/CT on lesion detection and treatment decision to CT alone. RESULTS: [68Ga]PSMA PET/CT revealed a total of 271 positive lesions, whereas CT detected 86 lesions (32%). Overall, the radiotherapy regime was changed in 55 of 120 cases (46%) based on the higher detection rate of [68Ga]PSMA PET/CT: in 15% of cases with PT, in 43% of cases with RL, and in 44% of cases with MD. CONCLUSION: [68Ga]PSMA PET/CT is superior to CT alone for lesion detection in prostate cancer, thereby significantly impacting on radiotherapy planning for primary disease, biochemical cancer relapse, and advanced disease of prostate cancer.

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.

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.

MRI-based quantitative susceptibility mapping (QSM) and R2* mapping of liver iron overload: Comparison with SQUID-based biomagnetic liver susceptometry.

PURPOSE: We aimed to determine the agreement between quantitative susceptibility mapping (QSM)-based biomagnetic liver susceptometry (BLS) and confounder-corrected R2* mapping with superconducting quantum interference device (SQUID)-based biomagnetic liver susceptometry in patients with liver iron overload. METHODS: Data were acquired from two healthy controls and 22 patients undergoing MRI and SQUID-BLS as part of routine monitoring for iron overload. Magnetic resonance imaging was performed on a 3T system using a three-dimensional multi-echo gradient-echo acquisition. Both magnetic susceptibility and R2* of the liver were estimated from this acquisition. Linear regression was used to compare estimates of QSM-BLS and R2* to SQUID-BLS. RESULTS: Both QSM-BLS and confounder-corrected R2* were sensitive to the presence of iron in the liver. Linear regression between QSM-BLS and SQUID-BLS demonstrated the following relationship: QSM-BLS = (-0.22 ± 0.11) + (0.49 ± 0.05) · SQUID-BLS with r2 = 0.88. The coefficient of determination between liver R2* and SQUID-BLS was also r2 = 0.88. CONCLUSION: We determined a strong correlation between both QSM-BLS and confounder-corrected R2* to SQUID-BLS. This study demonstrates the feasibility of QSM-BLS and confounder-corrected R2* for assessing liver iron overload, particularly when SQUID systems are not accessible. Magn Reson Med 78:264-270, 2017. © 2016 International Society for Magnetic Resonance in Medicine.

Detection rate of PET/CT in patients with biochemical relapse of prostate cancer using [68Ga]PSMA I&T and comparison with published data of [68Ga]PSMA HBED-CC.

PURPOSE: To determine the detection rate of PET/CT in biochemical relapse of prostate cancer using [68Ga]PSMA I&T and to compare it with published detection rates of [68Ga]PSMA HBED-CC. METHODS: We performed a retrospective analysis in 83 consecutive patients with documented biochemical relapse after prostatectomy. All patients underwent whole body [68Ga]PSMA I&T PET/CT. PET/CT images were evaluated for presence of local recurrence, lymph node metastases, and distant metastases. Proportions of positive PET/CT results were calculated for six subgroups with increasing prostate specific antigen (PSA) levels (<0.5 ng/mL, 0.5 to <1.0 ng/mL, 1.0 to <2.0 ng/mL, 2.0 to <5.0 ng/mL, 5.0 to <10.0, ≥10.0 ng/mL). Detection rates of [68Ga]PSMA I&T were statistically compared with published detection rates of [68Ga]PSMA HBED-CC using exact Fisher's test. RESULTS: Median PSA was 0.81 (range: 0.01 - 128) ng/mL. In 58/83 patients (70 %) at least one [68Ga]PSMA I&T positive lesion was detected. Local recurrent cancer was present in 18 patients (22 %), lymph node metastases in 29 patients (35 %), and distant metastases in 15 patients (18 %). The tumor detection rate was positively correlated with PSA levels, resulting in detection rates of 52 % (<0.5 ng/mL), 55 % (0.5 to <1.0 ng/mL), 70 % (1.0 to <2.0 ng/mL), 93 % (2.0 to <5.0 ng/mL), 100 % (5.0 to <10.0 ng/mL), and 100 % (≥10.0 ng/mL). There was no significant difference between the detection rate of [68Ga]PSMA I&T and published detection rates of [68Ga]PSMA HBED-CC (all p>0.05). CONCLUSIONS: [68Ga]PSMA I&T PET/CT has high detection rates of recurrent prostate cancer that are comparable to [68Ga]PSMA HBED-CC.

Thrombus-mimicking artifacts in two-point Dixon MRI: Prevalence, appearance, and severity.

PURPOSE: To evaluate the incidence and severity of potentially thrombus mimicking, flow-induced misallocation artifacts in a clinical setting. Two-point "Dixon" fat-water separation methods, with bipolar readout gradients, may suffer from flow-induced fat-water misallocation artifacts. If these artifacts occur within blood vessels, they may mimic thrombus. MATERIALS AND METHODS: Two-point Dixon coronal and axial images acquired in 102 consecutive patients were retrospectively evaluated for the presence of flow-induced artifacts in arteries and veins. Artifacts were graded on a 3-point scale (none, mild, severe) by two independent readers. Interreader agreement was evaluated with kappa statistics. RESULTS: Reader 1 reported 63 artifacts in 46 (45%) of the cases (severe in 19 cases, 18.6%). Reader 2 reported 51 artifacts in 43 (42.2%) of the cases (severe in 18 cases, 17.6%). Misallocation of fat and water was apparent in all datasets with severe artifacts, whereas variable signal intensity changes in water and fat images were observed in mild artifacts. Interreader agreement was good for artifacts appearing in coronal images (κ = 0.7) and fair for artifact appearance in axial images (κ = 0.24). CONCLUSION: Our study shows a high incidence of flow-induced mild and severe artifacts in a two-point Dixon method with bipolar readout gradients. This artifact should not be misinterpreted as intravascular thrombus. LEVEL OF EVIDENCE: 3 J. Magn. Reson. Imaging 2017;45:229-236.

How to write an original radiological research manuscript.

Many scientific manuscripts submitted for publication are limited by fundamental mistakes in their preparation, leading to rejection. We describe how to write a well-organized radiological research manuscript containing all of the important ingredients for effective communication of a hypothesis-driven scientific study in the context of medical imaging. KEY POINTS: • Mistakes in the preparation of scientific manuscripts lead to rejection. • Scientific writing, like any important skill, can be learned. • A well-developed approach will improve the quality of scientific writing. • High-quality scientific writing is essential to communicate research results. • A well-organized manuscript effectively communicates a hypothesis-driven scientific study.