MR-IMAGING OF HEPATOCELLULAR CARCINOMAS - EFFECT OF CU AND FE CONTENTS ON SIGNAL INTENSITY

Background: To elucidate the metallic factors contributing to the sign al intensities of hepatocellular carcinoma (HCC) on T1-weighted magnet ic resonance (MR) images and to determine whether or not changes in si gnal intensity contribute to the diagnosis of histological grading of HCC. Methods: In 35 patients immediately after surgery, the quantities of water, lipid, copper (Cu), iron (Fe), and manganese (Mn) were dete rmined in HCCs and the surrounding hepatic parenchyma. The correlation s among these findings, the histopathological findings, and the signal intensities of T1-weighted MR images were evaluated. Results: Among t he 35 HCCs, 12 (34%) were of high intensity, 14 (40%) were isointense, and 9 (26%) were of low intensity on T1-weighted images versus the su rrounding hepatic parenchyma. The paramagnetic ions, which contributed to the signal intensity patterns, were assumed to be Cu in HCCs (30.5 +/- 52.9 mu g/g ww), and Fe in the livers (106.2 +/- 86.8 mu g/g ww) and HCCs (87.7 +/- 49.1 mu g/g ww). In 12 HCCs with high intensity, on e was grade I, eight were grade II, and three were grade III according to Edmondson-Steiner's histopathological classification. Conclusions: Signal intensity and signal intensity patterns alone cannot be signs of low-grade malignancy because of the Fe in livers and in HCCs.