PLAIN AND GADOLINIUM-DTPA-ENHANCED MR-IMAGING OF HEPATOCELLULAR-CARCINOMA TREATED WITH TRANSARTERIAL CHEMOEMBOLIZATION

Background: To assess unenhanced and gadolinium-enhanced magnetic reso nance (MR) imaging patterns of hepatocellular carcinoma (HCC) treated with transarterial chemoembolization (TACE), Methods: Thirty-two patie nts with 4S HCC lesions underwent MR imaging before and 15 days after TACE. Fifteen lesions were then surgically resected. The remaining 33 lesions were not removed and were followed up with MR imaging at 3, 6, 12, and 18 months after treatment. Spin echo (SE) T1- and T2-weighted and gadolinium-enhanced SE T1-weighted sequences were employed. Quali tative evaluation of signal intensity pattern of the treated lesions w as performed in all cases. Histological evaluation and selective hepat ic arteriography were considered the gold standard of the study for th e 15 resected lesions and the 33 unresected lesions, respectively. Res ults: On follow-up enhanced T1-weighted images of the 15 resected lesi ons, seven showed no area of enhancement corresponding to complete nec rosis at histologic examination, The remaining eight resected lesions showed areas of enhancement, in sis of these cases, viable tumor tissu e was found at histology; in the other two lesions, histologic examina tion revealed the presence of complete tumor necrosis. In the group of resected lesions, T2-weighted images showed no pattern characteristic of necrosis. In 24 of 33 unresected lesions, loss of enhancement on f ollow-up enhanced Tli weighted images was a characteristic finding, wh ich correlated to devascularization at arteriography. Of these 24 lesi ons, 17 were completely hypointense on follow-up T2-weighted images ti le remaining seven showed small foci of hyperintensity, The other nine unresected lesions showed enhanced portions on followup enhanced T1-w eighted Images, which corresponded to hyperintense areas on T2-weighte d images,These findings correlated to persistence of hypervascular are as at arteriography. Conclusion: Gadolinium-enhanced T1-weighted MR im aging is a reliable method for evaluating the outcome of TACE treatmen t and is more accurate than unenhanced T2-weighted MR imaging.