T2-weighted and T1-weighted dynamic superparamagnetic iron oxide (ferucarbotran) enhanced MRI of hepatocellular carcinoma and hyperplastic nodules.

Background/Purpose: Iron oxide contrast medium (ferucarbotran) shortens both T1 and T2 relaxation time. We used the T2- and the T1-weighted dynamic ferucarbotran-enhanced magnetic resonance (MR) imaging to predict the histologic grade of hepatocellular carcinoma (HCC) and to distinguish HCC from hyperplastic nodules. Methods: Forty-three patients with 48 representative hepatic lesions (13 well differentiated HCC, 19 moderately differentiated HCC, 4 poorly differentiated HCC, 12 hyperplastic nodules) were included in the study. T1-weighted image, T2-weighted turbo spin echo, and T2*EPI (echo-planar) images were obtained before and after ferucarbotran injection. The percentage T2 signal intensity loss (T2 PSIL) of the tumors was calculated at 5 minutes and 25 minutes after contrast injection. The enhancement in dynamic T1 images was interpreted by two independent radiologists. Results: The T2 PSIL of well differentiated HCC was 39.5±8.23%, moderately differentiated HCC was 26.4±13.78%, poorly differentiated HCC was 4.4±9.42%, and hyperplastic nodules was 44.3±11.04%. Comparison of T2 PSIL showed significant differences in the three histologically graded HCCs (p＜0.001), but not between the well differentiated HCCs and hyperplastic nodules (p＞0.05). Delayed post-contrast (25 minutes) T2-weighted images were not necessary and shortened the examination time. In the post contrast dynamic T1 study, no significant differences between all the groups was seen. Conclusion: Ferucarbotran MR images help in differentiating the different histologic grades of HCC but T2 PSIL could not differentiate hyperplastic nodules from well differentiated HCC. Dynamic post contrast T1-weighted images provide no additional information.