Microvascular invasion in hepatocellular carcinoma: is it predictable with pretransplant MRI?

OBJECTIVE: The purpose of this article is to correlate clinicopathologic and MRI parameters with the presence of microvascular invasion at histopathologic examination in patients with hepatocellular carcinoma (HCC) who are undergoing liver transplantation.
MATERIALS AND METHODS: In this retrospective single-center study, we assessed 60 patients (47 men and 13 women; mean age, 58 years) with HCC who underwent liver transplantation and pretransplant MRI (performed within 90 days before liver transplantation). Two observers analyzed the following tumor parameters in consensus: number, size, T1 and T2 signal intensity, margins, presence of capsule or pseudocapsule, distance to closest vessel, distance to liver capsule, and quantitative tumor enhancement. The size and number of HCCs, tumor differentiation, and the presence or absence of microvascular invasion were determined at histopathologic examination. Odds ratios (ORs) were calculated and logistic regression analysis was performed to assess the utility of these clinicopathologic and imaging parameters for predicting microvascular invasion.
RESULTS: None of the clinical parameters or morphologic and enhancement MRI features of HCC was predictive of microvascular invasion. Tumor multifocality, on both MRI and pathologic examination, was the only variable that predicted microvascular invasion (OR = 2.43 and p = 0.013 for MRI; OR = 1.94 and p = 0.013 for pathologic examination). The presence of three or more tumors on MRI and four or more tumors at pathologic examination had high specificity (88.2% and 91.2%, respectively) for the prediction of microvascular invasion.
CONCLUSION: Tumor multifocality on MRI was the only parameter that correlated significantly with microvascular invasion. All other MRI tumor characteristics failed to predict microvascular invasion.