Detection and characterization of focal hepatic lesions: Mangafodipir vs. superparamagnetic iron oxide-enhanced magnetic resonance imaging

Purpose: To compare the mangafodipir-enhanced magnetic resonance (MR) and superparamagnetic iron oxide (SPIO)-enhanced images for their ability to detect and characterize focal hepatic lesions. Materials and Methods: Unenhanced, mangafodipir-enhanced, and SPIO-enhanced hepatic MR images obtained from 64 patients were analyzed. A total of 121 hepatic lesions were included: 66 hepatocellular carcinomas (HCCs), 26 metastases, 14 hemangiomas, 5 cysts, 3 cholangiocarcinomas, 4 focal nodular hyperplasias (FNHs), 2 abscesses, and 1 adenoma. Two radiologists independently reviewed the two sets of images in a random order: 1) the unenhanced and mangafodipir-enhanced images (the mangafodipir set) and 2) the unenhanced and SPIO-enhanced images (the SPIO set). This study compared the accuracy of lesion detection, the ability to distinguish between a benign and malignant lesion, and the ability to distinguish between the hepatocellular and non-hepatocellular origins of the lesions using the areas (Az) under the receiver operating characteristic (ROC) curve. Results: The overall accuracy for detecting focal lesions was significantly higher (P<0.05) with the SPIO set (Az = 0.846 and 0.871 for readers 1 and 2, respectively) than with the mangafodipir set (Az = 0.716 and 0.766). Most of the lesions detected only with the SPIO-enhanced MR images by the readers were small HCCs. For lesions larger than 15 mm, the sensitivities of the two contrast enhancement techniques were similar for both readers. The accuracy of the mangafodipir and SPIO sets in distinguishing between benign and malignant lesions was comparable. The accuracy for distinguishing between the hepatocellular and non-hepatocellular origins of the lesions was significantly higher (P<0.05) using the mangafodipir set (Az = 0.897 and 0.946) than using the SPIO set (Az = 0.741 and 0.833). Conclusion: SPIO- and mangafodipir-enhanced images were comparable for detection of focal hepatic lesions other than small HCCs, which were better detected on the SPIO-enhanced images. Mangafodipir-enhanced images are likely better than the SPIO-enhanced images for distinguishing between focal liver lesions with a hepatocellular or nonhepatocellular origin.