The Diagnosis of Hypovascular Hepatic Lesions Showing Hypo-intensity in the Hepatobiliary Phase of Gd-EOB- DTPA-enhanced MR Imaging in High-risk Patients for Hepatocellular Carcinoma

The aim of this study was to evaluate the histologic diagnosis of hypovascular hepatic lesions showing hypointensity on hepatobiliary phase images of gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced MRI (EOB-MRI). In 38 patients with hepatocellular carcinoma (HCC) after curative treatments and 18 patients with liver cirrhosis, 105 hypovascular nodules that were hypointense at the hepatobiliary phase of EOB-MRI were biopsied and the clinical usefulness of these EOB-MRI findings for the diagnosis of HCC was examined. Of the 105 nodules (median diameter＝12mm), 78 (74.3%), 11 (10.5%), and 16 (15.2%) were diagnosed as HCC, dysplastic, and non-neoplastic, respectively. The positive predictive value (PPV) of hypointensity at the hepatobiliary phase of EOB-MRI for the diagnosis of HCC increased to 77-90% when combined with the following factors: washout appearance on the delayed phase of triple-phase CT, hyperintensity in diffusion-weighted image of MRI, or the appearance of a hypoechoic part in ultrasonography. PPV increased to 100% when all 3 factors were positive. A relatively large proportion of hypovascular lesions that showed hypo-intensity in the hepatobiliary phase were confirmed to be HCC, and the accuracy of HCC increased when combined with other imaging findings.