Superparamagnetic iron oxide in the differential diagnosis of focal liver lesions at .5 T MRI

Introduction. We investigated the efficacy of superparamagnetic iron oxide (SPIO) in the characterization of focal liver lesions on MR images by means of quantitative and qualitative analysis. Material and methods. We examined 60 patients with at least one focal liver lesion on US images. Conventional T1-weighted spin echo (CSE), proton density and T2-weighted MR images were acquired before and after the injection of a SPIO agent (Endorem®, slow infusion, 15 micromoles Fe/kg body weight). A qualitative and a quantitative analysis were performed calculating the contrast enhancement rate in different kinds of lesions; the differences were related to the type of sequence statistically using Student's t-test for coupled samples. Results. Excellent correlation was found with biopsy findings in all but two patients who were false positive for hepatocellular carcinoma (scar on cirrhotic liver). T1-weighted sequences after AMI-25 injection were the most specific ones in hemangioma characterization; PD were the most sensitive sequences in the detection and characterization of liver metastases. T2- weighted sequences were helpful only in the detection of focal liver lesions but they were not specific. Conclusions. In conclusion, SPIO-enhanced MRI is an excellent imaging tool for the differential diagnosis of focal liver lesions, with a good specificity for the differential diagnosis of hemangioma and metastasis. It is also helpful to distinguish benign from malignant lesions.