Additional Value of SPIO-Enhanced MR Imaging for the Noninvasive Imaging Diagnosis of Hepatocellular Carcinoma in Cirrhotic Liver

Abstract

The purpose of this study is to determine whether adding superparamagnetic iron oxide (SPIO)-enhanced MR images to the 2 dynamic imaging modalities, triphasic CT scan and dynamic MR imaging (MRI), improves the diagnosis of hepatocellular carcinomas (HCCs) compared with the noninvasive diagnosis provided by the European Society of Study of the Liver (EASL) criteria. This retrospective study included 108 patients with 152 histologically confirmed hepatocellular nodules, ie, 28 dysplastic nodules and 124 HCCs. Of the 124 HCCs, 79 were larger than 2 cm in diameter, 34 were between 1 to 2 cm, and 11 were less than 1 cm. The reviewers retrospectively analyzed by consensus the hypervascularity of the nodules on both dynamic CT and MR images as well as their signal intensity on SPIO-enhanced images. Sensitivity, specificity, and diagnostic accuracy were assessed based on the EASL noninvasive diagnostic criteria for HCC and SPIO-combined EASL criteria. Seventeen (14%) of 124 HCCs were hypovascular HCC according to both imaging modalities, and hypovascular HCC was more frequently seen in the subgroup of HCC < or = 2 cm in diameter. A significant improvement in the sensitivity (78% to 96%) for diagnosing HCCs larger than 2 cm in diameter, was achieved by adding SPIO-enhanced MR images to 2 dynamic studies compared with the noninvasive diagnosis according to the EASL criteria (P < 0.01). When the EASL criteria were applied to the 34 HCCs of 1 to 2 cm in diameter, 21 lesions (62%) were correctly diagnosed using the EASL criteria and 29 lesions (85%) according to the SPIO-combined EASL criteria. Adding SPIO-enhanced MR images to the dynamic imaging modalities, including triphasic CT and dynamic MRI, improves the noninvasive diagnosis of HCCs compared with using only the EASL criteria, especially when attempting to diagnose hypovascular or slightly hypervascular HCCs. As these images combine information regarding the function or deficit of Kupffer cells within the hepatic nodules with vascularity information, combining sequentially acquired SPIO-enhanced MRI with dynamic MRI could be considered to be the single-step imaging modality with a high degree of accuracy in the diagnostic work-up of small HCCs.