SUPERPARAMAGNETIC IRON OXIDE-ENHANCED VERSUS GADOLINIUM-ENHANCED MR-IMAGING FOR DIFFERENTIAL-DIAGNOSIS OF FOCAL LIVER-LESIONS

PURPOSE: To assess AMI-25-versus gadolinium-enhanced magnetic resonanc e (MR) imaging in the differential diagnosis of liver tumors. MATERIAL S AND METHODS: Twenty-nine patients with liver tumors underwent unenha nced, AMI-25-enhanced (15 mu mol/kg), and gadolinium-enhanced(0.1 mmol /kg) imaging within 2 weeks. RESULTS: A significant (P <.05) differenc e in percentage signal intensity loss (PSIL) was seen in benign tumors on AMI-25-enhanced proton-density-weighted images (nine focal nodular hyperplasia [FNH], 41%; one adenoma, 32.4%) versus malignant tumors. Gadolinium-enhanced T1-weighted gradient-echo images showed strong enh ancement in benign lesions (seven FNH, 147.5%; one adenoma, 91.3%) and moderate enhancement in malignant tumors (eight hepatoeellular carcin omas, 116.2%; 11 metastases, 39.7%). Receiver operating characteristic analysis revealed a threshold PSIL of 10% on AMI-25-enhanced images a s the most essential criteria to distinguish benign from malignant les ions (sensitivity, 88%; specificity. 89%). Interobserver analysis for two observers revealed specificity of 93% for AMI-25-enhanced imaging versus 81.5% for gadolinium-enhanced MR imaging. CONCLUSION: AMI-25 de creased the SI of benign tumors and helped differentiate benign from m alignant tumors.