Diagnostic and Interventional Radiology

Nonalcoholic fatty liver disease (NAFLD) can progress to liver cirrhosis and is predicted to become the most frequent indication for liver transplantation in the near future. Noninvasive assessment of NAFLD is important for diagnosis and patient management. This study aims to prospectively determine the liver stiffness and T1 and T2 values in patients with NAFLD and to compare the diagnostic performance of magnetic resonance elastography (MRE) and mapping techniques in relation to the proton density fat fraction (PDFF). Eighty-three patients with NAFLD and 26 participants with normal livers were imaged with a 1.5 T scanner. PDFF measurements obtained from the multiecho Dixon technique were used to quantify the liver fat. MRE, native T1 mapping (modified Look-Locker inversion recovery [MOLLI] schemes 5(3)3, 3(3)3(3)5, and 3(2)3(2)5 and the B1-corrected variable flip angle [VFA] method), and T2 mapping values were correlated with PDFF. The diagnostic performance of MRE and the mapping techniques were analyzed and compared. T1 values measured with the MOLLI schemes and the B1-corrected VFA (P < 0.001), and the stiffness values from MRE (P = 0.047) were significantly higher in the NAFLD group. No significant difference was found between the groups in terms of T2 values (P = 0.127). In differentiation of the NAFLD and control groups, the B1-corrected VFA technique had slightly higher accuracy and area under the curve (AUC) than the MOLLI schemes. In the NAFLD group, there was a good correlation between the PDFF, MOLLI 3(3)3(3)5 and 3(2)3(2)5, and VFA T1 measurements (r=0.732; r=0.735; r=0.716, P < 0.001, respectively). Liver T1 mapping techniques have the potential to distinguish steatotic from nonsteatotic livers, and T1 values seem to have a strong correlation with the liver fat content.

Background and Aims: Magnetic resonance elastography (MRE) is an accurate, continuous biomarker of liver fibrosis; however, the optimal combination with clinical factors to predict the risk of incident hepatic decompensation is unknown. Therefore, we aimed to develop and validate an MRE-based prediction model for hepatic decompensation for patients with NAFLD. Approach and Results: This international multicenter cohort study included participants with NAFLD undergoing MRE from 6 hospitals. A total of 1254 participants were randomly assigned as training (n = 627) and validation (n = 627) cohorts. The primary end point was hepatic decompensation, defined as the first occurrence of variceal hemorrhage, ascites, or HE. Covariates associated with hepatic decompensation on Cox-regression were combined with MRE to construct a risk prediction model in the training cohort and then tested in the validation cohort. The median (IQR) age and MRE values were 61 (18) years and 3.5 (2.5) kPa in the training cohort and 60 (20) years and 3.4 (2.5) kPa in the validation cohort, respectively. The MRE-based multivariable model that included age, MRE, albumin, aspartate aminotransferase, and platelets had excellent discrimination for the 3- and 5-year risk of hepatic decompensation (c-statistic 0.912 and 0.891, respectively) in the training cohort. The diagnostic accuracy remained consistent in the validation cohort with a c-statistic of 0.871 and 0.876 for hepatic decompensation at 3 and 5 years, respectively, and was superior to Fibrosis-4 in both cohorts (p < 0.05). Conclusions: An MRE-based prediction model allows for accurate prediction of hepatic decompensation and assists in the risk stratification of patients with NAFLD.

To determine the accuracy of magnetic resonance imaging-proton density fat fraction (MRI-PDFF) measurements for detecting liver fat content in potential living liver donors and to compare these results using liver biopsy findings. A total of 139 living liver donors (men/women: 83/56) who underwent MRI between January 2017 and September 2021 were included in this analysis retrospectively. The PDFFs were measured using both MR spectroscopy (MRS) and chemical shift-based MRI (CS-MRI) for each donor in a blinded manner. Significant positive correlations were found between liver biopsy and MRS-PDFF and CS-MRI PDFF in terms of hepatic steatosis detection [r = 0.701, 95% confidence interval (CI): 0.604-0.798, r = 0.654, 95% CI: 0.544-0.765, P < 0.001, respectively). A weak level correlation was observed between liver biopsy, MRI methods, and vibration-controlled transient elastography attenuation parameters in 42 available donors. Based on receiver operating characteristic (ROC) analysis, MRS-PDFF and CS-MRI PDFF significantly distinguished >5% of histopathologically detected hepatic steatosis with an area under the ROC curve (AUC) of 0.837 ± 0.036 (P < 0.001, 95% CI: 0.766-0.907) and 0.810 ± 0.036 (P < 0.001, 95% CI: 0.739-0.881), respectively. The negative predictive values (NPVs) of MRS-PDFF and CS-MRI PDFF were 88.3% and 81.3%, respectively. In terms of distinguishing between clinically significant hepatic steatosis (≥10% on histopathology), the AUC of MRS-PDFF and CS-MRI were 0.871 ± 0.034 (P < 0.001 95% CI: 0.804-0.937) and 0.855 ± 0.036 (P < 0.001, 95% CI: 0.784-0.925), respectively. The NPVs of MRS-PDFF and CS-MRI were 99% and 92%, respectively. The methods of MRS-PDFF and CS-MRI PDFF provide a non-invasive and accurate approach for assessing hepatic steatosis in potential living liver donor candidates. These MRI PDFF techniques present a promising clinical advantage in the preoperative evaluation of living liver donors by eliminating the requirement for invasive procedures like liver biopsy.

PURPOSE We aimed to evaluate the spectrum of magnetic resonance cholangiopancreatography (MRCP) findings in patients with ectopic opening of the common bile duct (CBD) into the duodenal bulb and to determine the effectiveness of the MRCP technique in diagnosis. METHODS Morphologic and morphometric MRCP/MRI features in 16 patients and 36 controls were retrospectively analyzed by 2 radiologists. The frequency of MRCP findings was determined. The significance of the difference between the MRCP observations in patients and controls was evaluated statistically and the diagnostic effectiveness of MRCP was investigated. RESULTS Hook-shaped ending of CBD and bulbar deformity were the most frequent morphologic findings seen on MRCP in the ectopic bulbar opening. Mean pylorus-papilla distance and mean CBD length were significantly shorter and the median diameter of CBD was significantly larger than the control group (patients: 28.6 +/- 15.3 mm, 33.7 +/- 12.8 mm, 8.6 (2-16) mm; controls: 66.7 +/- 11.7 mm, 50.3 +/- 14.4 mm, 3.2 (1.5-10) mm, P <.001, respectively). Receiver operating curve analysis showed sensitivity and specificity of MRCP in the diagnosis to be 87.5% and 100%, respectively, if any 3 of the 4 signs (hook-shaped ending of CBD, bulbar deformity, large, and short CBD) were present in a patient whose pylorus-papilla distance was <50 mm. CONCLUSION At MRCP, the presence of short and large CBD with a hook-shaped ending in the deformed duodenal bulb may support the diagnosis of ectopic biliary drainage.