Noninvasive Magnetic Resonance Imaging Models for Staging Hepatic Fibrosis and Grading Inflammatory Activity in Patients with Chronic Hepatitis B

Abstract

Background: In patients with chronic hepatitis B (CHB), the hepatic fibrosis (HF) stage and inflammatory activity grade are critical indicators for therapeutic strategies and prognosis. However, patients with CHB usually show no symptoms or only present with mild abdominal distension, making it difficult to stage HF and grade inflammatory activity. Invasive liver biopsy is the current gold standard for assessing HF and inflammation, but this technique has some limitations. Magnetic resonance imaging (MRI), a noninvasive and promising technique for HF evaluation, has been increasingly adopted in such cases. Diffusion-weighted imaging (DWI) with multiple b-values, a non-contrast MRI method, has become a topic of interest in the assessment and staging of HF. This study aimed to assess the value of various diffusion parameters obtained from monoexponential, biexponential, and stretched-exponential DWI models in predicting the HF stage and inflammatory activity grade in patients with CHB. Methods: 102 patients with CHB and 30 healthy volunteers underwent prospective DWI with 13 b-values on a 3T MRI unit. The standard apparent diffusion coefficient (ADCst) was calculated using a monoexponential DWI model. The true diffusion coefficient (Dt), pseudo-diffusion coefficient (Dp), and perfusion fraction (f) were calculated using a biexponential DWI model. The distributed diffusion coefficient (DDC) and water-molecule diffusion heterogeneity index (α) were calculated using a stretched-exponential DWI model. The Kruskal-Wallis H test, Mann-Whitney U test, and receiver operating characteristic (ROC) analysis were performed for all of the DWI parameters. Findings: Patients with significant fibrosis (≥F2) had lower hepatic ADCst, Dt and DDC values than those without or with early fibrosis (≤F1) and healthy volunteers (all P 0.05). Interpretation: Dt and DDC are promising indicators and outperform ADCst for diagnosing significant fibrosis and advanced fibrosis. While both Dt and DDC have similar diagnostic performance compared with ADCst in inflammatory activity grading in patients with CHB. Funding: This research was supported by the National Key R&D Program of China (2017YFE0103600), National Natural Science Foundation of China (81720108021, 81772009, 81601466, 81641168, 31470047), Scientific and Technological Research Project of Henan Province (182102310162). Declaration of Interest: F.F. disclosed no relevant relationships. X.L disclosed no relevant relationships. Y.L. disclosed no relevant relationships C.C. disclosed no relevant relationships. Y.B. disclosed no relevant relationships. J.S. disclosed no relevant relationships. D.S. disclosed no relevant relationships. J.T. disclosed no relevant relationships M.W. disclosed no relevant relationships. Ethical Approval: This prospective study was approved by the institutional review board, and informed consent was obtained from all participants.