Histogram analysis of noncancerous liver parenchyma on gadoxetic acid-enhanced MRI: predictive value for liver function and pathology

Purpose: To clarify whether the heterogeneity of hepatic parenchyma in the hepatobiliary phase on gadoxetic acid-magnetic resonance (MR) imaging is correlated with liver damage. Materials and methods: We retrospectively examined the cases of 98 patients with or without chronic liver disease who underwent gadoxetic acid-enhanced 3T MR imaging before a hepatectomy between December 2010 and October 2014. For the evaluation of the heterogeneity of the signal intensity in the hepatobiliary phase, we placed the region of interest on the hepatic parenchyma, and the skewness and kurtosis were calculated using ImageJ software. A discriminant analysis was performed to examine the routine preoperative laboratory test results including indocyanine green retention at 15 min (ICG-R15), necro-inflammation grade, and liver fibrosis stage according to the METAVIR system: A0/1 (n = 69) and A2 (n = 29); F0/1 (n = 47), F2/3 (n = 31), and F4 (n = 20). Results: The combination of skewness and kurtosis could discriminate the high ICG-R15 (>20) and low (<20) groups (lambda; 0.925, p = 0.025), necro-inflammatory grade (lambda; 0.926, p = 0.026), and fibrosis stage (lambda; 0.752, p < 0.0001) with statistical significance. The difference between the patients with normal values and those with an abnormal platelet count or aspartate transaminase level was also detectable (lambda; 0.901, p < 0.007, and lambda; 0.864, p = 0.001, respectively). Conclusion: Histogram analyses of the hepatobiliary phase of gadoxetic acid-enhanced MR imaging have potential as a biomarker for the assessment of liver function, liver fibrosis, and necro-inflammation.