Superparamagnetic iron oxide enhanced magnetic resonance imaging of rat liver with hepatocellular carcinoma and benign hyperplastic nodule

RATIONALE AND OBJECTIVES. The authors assess the potential of a new superparamagnetic iron oxide (SPIO) in grading hepatocellular carcinoma (HCC) histologically and in differentiating HCC from benign hyperplastic nodule (HPN). METHODS. Nine Wistar rats (with poorly to moderately differentiated HCC, well-differentiated HCC, and HPN) received drinking water containing N-nitrosomorpholine, and were examined by magnetic resonance imaging (4.7 tesla). Spin-echo images (repetition time/echo time, 600/24.5 mseconds) were obtained before and 15 minutes after intravenous administration of 10 mu mol Fe/kg of SH U 555A. RESULTS. poorly to moderately differentiated and well-differentiated HCC showed no significant change in signal-to-noise ratio (SNR) 15 minutes after contrast, whereas HPN showed a significant decrease in SNR. The contrast-to-noise ratio (CNR) between each kind of tumor and adjacent liver parenchyma showed a significant increase at 15 minutes after contrast. CONCLUSIONS. The SPIO discussed in this article may help to differentiate HCC from HPN, but it remains difficult to grade hepatocellular carcinoma histologically.