Non-invasive assessment of liver fibrosis in autoimmune hepatitis: Diagnostic value of liver magnetic resonance parametric mapping including extracellular volume fraction

Abstract

Purpose Autoimmune hepatitis (AIH) is an immune-mediated chronic liver disease that leads to severe fibrosis and cirrhosis. The aim of this study was to determine the diagnostic value of T1 and T2 mapping as well as extracellular volume fraction (ECV) for non-invasive assessment of liver fibrosis in AIH patients. Methods In this prospective study, 27 patients (age range: 19–77 years) with AIH underwent liver MRI. T1 and T2 relaxation times as well as ECV were quantified by mapping techniques. The presence of significant fibrosis (≥ F2) was defined as magnetic resonance elastography (MRE)-based liver stiffness ≥ 3.66 kPa. MRE was used as reference standard, against which the diagnostic performance of MRI-derived mapping parameters was tested. Diagnostic performance was compared by utilizing receiver-operating characteristic (ROC) analysis. Results MRE-based liver stiffness correlated with both, hepatic native T1 (r = 0.69; P < 0.001) as well as ECV (r = 0.80; P < 0.001). For the assessment of significant fibrosis, ECV yielded a sensitivity of 85.7% (95% confidence interval (CI): 60.1–96.0%) and a specificity of 84.6% (CI 60.1–96.0%); hepatic native T1 yielded a sensitivity of 85.7% (CI 60.1–96.0%); and a specificity of 76.9% (CI 49.7–91.8%). Diagnostic performance of hepatic ECV (area under the curve (AUC): 0.885), native hepatic T1 (AUC: 0.846) for assessment of significant fibrosis was similar compared to clinical fibrosis scores (APRI (AUC: 0.852), FIB-4 (AUC: 0.758), and AAR (0.654) (P > 0.05 for each comparison)). Conclusion Quantitative mapping parameters such as T1 and ECV can identify significant fibrosis in AIH patients. Future studies are needed to explore the value of parametric mapping for the evaluation of different disease stages.

Diagnostic value of magnetic resonance parametric mapping for non-invasive assessment of liver fibrosis in patients with primary sclerosing cholangitis

“…Another promising MRI technique is relaxometry including ECV calculation. Significant correlations between hepatic T1, T2 as well as ECV with liver fibrosis have been already sufficiently described in the previous studies [ 17 , 20 , 21 , 37 – 39 ]. Liver fibrosis is defined as the accumulation of extracellular matrix proteins produced by fibrogenic cell populations in response to tissue injury.…”

“…ECV can be calculated from the change in relaxation rate (R1 = 1/T1) of blood and parenchyma corrected for the hematocrit [ 17 , 19 ]. Although several studies investigated the role of T1 and T2 mapping techniques as well as ECV for liver fibrosis assessment [ 16 , 17 , 20 – 23 ], reliable data investigating these techniques in patients with PSC are still missing. Therefore, the goal of the present study was to explore the diagnostic value of MRI mapping parameters, including ECV to diagnose significant fibrosis in PSC patients using MRE-derived liver stiffness as a reference standard.…”

Synthetic extracellular volume fraction without hematocrit sampling for hepatic applications

“…This process leads to the extension of extracellular space and an increased accumulation of extracellular contrast agents, which is reflected by prolonged native T1 relaxation times and increased ECV of the liver. Therefore, with a growing body of evidence, calculation of ECV is considered a new promising potential biomarker for non-invasive assessment of liver fibrosis [7][8][9]. Therefore, parametric MRI mapping including ECV requires routine clinical use of mapping beyond morphological sequences.…”

“…Liver MR-elastography was performed with a 2D gradient-recalled echo sequence to acquire liver elasticity maps with motion-encoding gradients. MR-elastography measurements were performed as previously described [8].…”

“…Therefore, calculation of ECV requires Hct sampling. MRI-derived ECV using T1 mapping techniques is currently of increased interest as a new non-invasive tool for liver fibrosis assessment [7][8][9][10][11][12]. There are already studies, demonstrating a high diagnostic performance of ECV in liver fibrosis assessment in both, animal and human models [7,9].…”