EXTRACAPSULAR INVASION OF SMALL HEPATOCELLULAR-CARCINOMA - MR AND CT FINDINGS

Objective: The purpose was to examine whether MR and CT imaging can de tect extracapsular invasion of hepatocellular carcinoma (HCC) and, if this is possible, to determine its characteristic signs on MR and CT i mages. Materials and Methods: Thirty-eight patients with small HCC (le ss than or equal to 3.0 cm in diameter) were studied to correlate the findings in surgically resected specimens with the findings on MR and CT images. Results: Ten of 38 patients had histologically proven extra capsular invasion of HCC. Of these 10 patients with extracapsular inva sion, partial projections of the tumor into the surrounding area or sa tellite nodules in the immediate vicinity of the tumor were observed i n 9 patients on T1-weighted images and in 5 patients on postcontrast C T images. Partial tumor projection or satellite nodules were not obser ved in patients without extracapsular invasion of HCC. The detection r ate for these characteristic signs was 90% on MR and 50% on CT. Conclu sion: Magnetic resonance and CT imaging were useful for detection of e xtracapsular invasion of HCC. The characteristic signs for extracapsul ar invasion of HCC were partial tumor projection into the surrounding area and satellite nodules in the immediate vicinity of the tumor.