Non-invasive liver stiffness assessment using tagged MRI of cardiac-induced liver motion : comparison of various methods to diagnose liver fibrosis

Abstract

PURPOSE: The purpose of this study was to assess liver stiffness by using tagged-MRI to quantify the cardiac-induced motion and deformation in the liver. And we compared tagged MRI with other non-invasive tests to reflect hepatic fibrosis to explore the relationship between the assessment using tagged MRI and grading of hepatic fibrosis. MATERIALS AND METHODS: We studied a total of 85 patients with tagged MRI who underwent liver MRI for various diagnostic purposes from April 2010 to August 2010 in our institution. Tagged images were acquired in 3 coronal and 3 sagittal planes encompassing both the liver and the heart, using 3T MRI systems (Tim Trio; Siemens). The displacement and strains were calculated using a Gabor filter bank. The maximum displacement (MaxDisp) was found over the cardiac cycle, as well as the local maximum P1 (MaxP1) and minimum P2 strains (minP2). Patients were divided into three groups (no fibrosis, fibrosis and cirrhosis) according to various known methods reflecting the degree of liver fibrosis; APRI, Child-Pugh classification, transient elastography (fibroscan) and pathologic result. Group comparisons were made using ANOVA test.RESULTS: Statistically significant differences were found between groups in APRI (n=85, MaxDisp 2.9±0.9, 2.3±0.7, 2.1±0.6; MaxP1 0.05±0.02, 0.04±0.02, 0.03±0.01; minP2 -0.06±0.02, -0.04±0.02, -0.04±0.01, respectively), Child-Pugh score (n=85, MaxDisp 3.0±0.9, 2.5±0.7, 1.9±0.7; MaxP1 0.06±0.02, 0.04±0.01, 0.02±0.01; minP2 -0.06±0.02, -0.05±0.01, -0.03±0.01, respectively), transient elastography (n=36, MaxDisp 3.5±1.3, 2.6±0.6, 2.5±0.8; MaxP1 0.07±0.02, 0.04±0.02, 0.03±0.01; minP2 -0.07±0.02, -0.05±0.02, -0.04±0.01, respectively; p<0.05 for all). But there was no significant difference between groups in pathologic correlation. (n=37, p=0.156, 0.234 and 0.108, respectively)CONCLUSION: The performance of this method for assessing the liver stiffness based on tagged MRI of cardiac-induced liver motion compares favorably with other noninvasive tests for the presence of liver fibrosis. This method has a significant potential as a non-invasive imaging in detecting early change of hepatic fibrosis and has the potential to replace liver biopsy in some patients.