Hepatocellular Carcinomas Smaller Than 4 cm Supplied by the Intercostal Artery: Can We Predict Which Intercostal Artery Supplies the Tumor?

OBJECTIVE To predict which intercostal artery supplies a tumor by examining the spatial relationship between hepatocellular carcinoma (HCC) and the intercostal artery feeding the tumor on transverse computed tomography (CT) images. MATERIALS AND METHODS Between January 2000 and September 2009, 46 intercostal arteries supplying HCCs smaller than 4 cm were noted in 44 patients, and CT scans and angiograms of these patients were retrospectively reviewed. The intercostal artery feeding the tumor was marked on the CT scan showing the center of the tumor. In addition, its spatial relationship with the tumor center was examined. The angle of the tumor location was measured on the transverse CT scan in the clockwise direction from the sagittal line on the virtual circle centered in the right hemithorax. Correlations between the angle of the tumor location and the level of the tumor-feeding intercostal artery were assessed with the Spearman rank coefficient. RESULTS Of 46 intercostal arteries feeding HCC, 39 (85%) were the first ones observed from the tumor center in a counterclockwise direction on the transverse CT image containing the tumor center. The level of the tumor-feeding intercostal artery was significantly correlated with the angle of the tumor, as the posteriorly located tumor tends to be supplied by lower intercostal arteries, while the laterally located tumor by upper intercostal arteries (Spearman coefficient = -0.537; p < 0.001). CONCLUSION We can predict the tumor feeder with an accuracy of 85% as the first intercostal artery encountered from the tumor center in a counterclockwise direction on a transverse CT image.