Liver findings in newly diagnosed, treatment-naive patients with Crohn's disease: a preliminary study of MRI proton density fat fraction and extracellular volume fraction.
OBJECTIVE This study aimed to investigate the applicability of MRI proton density fat fraction (MRI-PDFF) and extracellular volume fraction (ECV) in detecting liver injury in patients with intestinal Crohn's disease (CD). Additionally, it evaluated the relationships among multi-parametric imaging indicators, clinical scores, and serological markers. METHODS A total of 107 patients with CD were enrolled in this retrospective study conducted from December 2021 to October 2024. All subjects underwent MRI scans with Iterative decomposition of water and fat with echo asymmetry and least-squares estimation quantitation (IDEAL-IQ) sequence to generate the MRI-PDFF values. Moreover, pre- and post-contrast liver T1 mapping was performed at the level of the liver hilum. The ECV value was calculated by inputting the patient's hematocrit level (HCT). Based on the Harvey-Bradshaw index (HBI), the clinical score was assessed along with serological markers, including alkaline phosphatase (ALP), alanine transaminase (ALT), aspartate aminotransferase (AST), erythrocyte sedimentation rate (ESR), fecal calprotectin (FC), and γ-glutamyl transferase (GGT). Receiver operating characteristic (ROC) curves were plotted, and the area under the curve (AUC) was calculated to evaluate the application value of ECV and MRI-PDFF value compared with ALP, ALT, AST, ESR, FC, and GGT. The correlation of the ECV and MRI-PDFF values with clinical score and serological markers was assessed using correlation coefficients. RESULTS In examining different levels of intestinal inflammation activity, significant statistical differences were observed in MRI-PDFF and ECV values (p < 0.001). ROC curve analysis indicated that MRI-PDFF and ECV exhibited superior discriminatory abilities, with AUCs of 0.773 and 0.843, respectively (ALP, ALT, AST, GGT, ESR, and FC of 0.512, 0.566, 0.530, 0.551, 0.693, 0.716). Both MRI-PDFF values (r = 0.520, r = 0.246, r = 0.339, all p < 0.001) and ECV (r = 0.534, r = 0.435, r = 0.433, all p < 0.001) were positively correlated with HBI, ESR, and FC values. CONCLUSION This study suggests that chronic systemic inflammation may lead to liver injury in patients with CD. Liver MRI can help assess and monitor liver involvement that may not be visually detectable in these patients. CLINICAL TRIAL NUMBER Not applicable.