Hemangioma and hepatocellular carcinoma: distinction with superparamagnetic iron oxide enhanced MR imaging

To compare liver hemangioma with hepatocellular carcinoma (HCC), as seen on superparamagnetic iron oxide (SPIO)-enhanced MR images. The study involved 30 patients with 51 focal hepatic mass lesions (31 hemangiomas, 20 HCCs). Breath-hold T1-weighted fast low angle shot (FLASH) and respiratory-triggered T2-weighted turbospin echo (TSE) images were obtained at 1.5T before and after intravenous administration of SPIO particles. For quantitative analysis, percentage signal intensity change (PSIC) and contrast-to-noise ratio (CNR) of the lesions were calculated for T1-weighted FLASH and T2-weighted TSE before and after intravenous administration of SPIO particles. In addition, lesion conspicuity and imaging artifacts were analyzed qualitatively. After SPIO administration, percentage signal intensity increase on T1-weighted FLASH images was 73.0 ± 22.1% for hemangiomas and 21.8 ±12.6% for HCCs, the difference being significant (p less than 0.05). Taking a signal increase of 40% on postcontrast T1-weighted FLASH as the cut-off value, sensitivity and specificity for hemangiomas were 96.8% and 100%, respectively. In addition, the percentages of signal intensity loss on T2-weighted TSE images for hemangiomas and HCCs were 35.5 ± 17.2% and 0.2 ± 10.5%, respectively (p less than 0.05). A comparison of lesion to liver CNR before and after SPIO infusion showed readings-for hemangiomas and HCCs, respectively- of 15.4 ± 6.0 and 4.7 ± 4.4 on T1-weighted FLASH images, and -2.6 ± 0.7 and 2.7 ± 4.4 on T2-weighted TSE images (p less than 0.05). Qualitative analysis indicated that the conspicuity of HCCs was noticeably greater on postcontrast T2-weighted TSE images than on precontrast images (p less than 0.05). The positive enhancement seen on T1-weighted FLASH images and the negative enhancement on T2-weighted TSE observed in liver hemangiomas after the administration of SPIO particles are valuable diagnostic features that can help characterize hemangiomas and differentiate them from HCCs. (author)