Magnetic Resonance Elastography and Diffusion Weighted Imaging in the Evaluation of Hepatic Fibrosis in Chronic Hepatitis B

Abstract

Background/aims: Comparison of the accuracy of magnetic resonance elastography (MRE) and diffusion weighted imaging (DWI) for the diagnosis of liver fibrosis in patients with chronic hepatitis B (CHB).

Methods: In this retrospective analysis, we investigated 63 patients with CHB and liver fibrosis. DWI was performed with both breath-hold (DWI-BH) and free-breathing (DWI-FB) sequences (b=0, 500). The mean liver stiffness and apparent diffusion coefficient (ADC) were calculated by drawing regions of interest maps. Fibrosis staging according to the METAVIR system was independently performed by an experienced pathologist. A receiver operating curve (ROC) analysis was conducted to determine the accuracy of MRE, DWI-BH and DWI-FB in the detection and stratification of liver fibrosis. The performance of the detection of significant fibrosis (≥F2), advanced fibrosis (≥F3), and cirrhosis (F4) was also evaluated by comparing areas under the ROC.

Results: There was a moderate and significantly negative correlation between the ADC values and liver stiffness. The accuracies for the detection of ≥F2/≥F3/F4 stage fibrosis with DWI-FB, DWI-BH and MRE were 0.84/0.76/0.72, 0.72/0.83/0.79 and 0.99/0.99/0.98, respectively. The performance of MRE was significantly better than DWI-FB and DWI-BH. There were no significant differences between the performance of DWI-FB and DWI-BH.

Conclusions: MRE is more accurate than DWI for the detection and stratification of liver fibrosis in CHB.

Keywords: Accuracy; Cirrhosis; Diffusion weighted imaging; Elastography; Liver cirrhosis.

Fig. 1

Examples of representative axial T2 weighted images (first column), diffusion weighted imaging (DWI; second column), apparent diffusion coefficient (ADC) maps (third column) and stiffness maps from magnetic resonance elastography (MRE; fourth column). DWI images in the top and third rows were obtained from breath-hold DWI sequences, whereas the second and fourth rows were obtained from free-breathing DWI sequences. In the top and second rows, the ADC and MRE values correctly classified the cases as stage F2 and F4 fibrosis. In the third and fourth rows, the MRE values correctly classified the cases as stage F2 and F4 fibrosis; however, the ADC values failed to correctly classify these cases.

Fig. 2

Box and whisker plots demonstrate the apparent diffusion coefficient (ADC) values for diffusion weighted imaging-breath hold (A) and diffusion weighted imaging-free breathing (B) and the liver stiffness (C) values for magnetic resonance elastography (MRE) in liver stages F0–1 through F4.

Fig. 3

Comparison of the area under receiver operating curves indicated significantly better performance of magnetic resonance elastography (MRE) for all stages of fibrosis than that of diffusion weighted imaging-breath hold (DWI-BH) and diffusion weighted imaging-free breathing (DWI-FB). ADC, apparent diffusion coefficient.