Hepatic lesion detection and characterization: Value of nonenhanced MR imaging, superparamagnetic iron oxide-enhanced MR imaging, and spiral CT-ROC analysis

PURPOSE: To determine the accuracy for detection and characterization of fo cal hepatic lesions of nonenhanced, superparamagnetic iron oxide (SPIO)-enh anced, or a combination of nonenhanced and SPIO-enhanced MR imaging and con trast-enhanced spiral computed tomography (CT). MATERIALS AND METHODS: Spiral CT and T2-weighted SPIO-enhanced (ferucarbotr an-enhanced) MR imaging were performed in 35 patients within 2 weeks before surgery for malignant hepatic lesions. Only malignant lesions with histopa thologic proof were considered. A total of 875 images with and 800 images w ithout focal lesions were presented to five readers, who were asked to asse ss the presence and characterization of lesions by using a five-point confi dence scale. Receiver operating characteristic analysis was performed. RESULTS: Nonenhanced and SPIO-enhanced images together and SPIO-enhanced im ages alone yielded the best performance for lesion detection. No difference s were found among all imaging techniques with regard to lesion characteriz ation (benign vs malignant). The combined approach resulted in larger area under the ROC curve (A(z) = 0.9062) and accuracy (85.3%) (P < 0.02), as com pared with SPIO-enhanced MR imaging (A(z) = 0.8667; accuracy, 73.1%). CONCLUSION: SPIO-enhanced T2-weighted MR imaging was more accurate than non enhanced T1-weighted and T2-weighted MR imaging and contrast-enhanced spira l CT for the detection of focal hepatic lesions. The combined analysis of n onenhanced and SPIO-enhanced images was more accurate in the characterizati on of focal hepatic lesions than was review of SPIO-enhanced images alone.