RIM ENHANCEMENT IN COLORECTAL METASTASES AT CT DURING INFUSION HEPATIC ARTERIOGRAPHY - DOES IT REPRESENT LIVER PARENCHYMA OR LIVE TUMOR-CELL ZONE

Purpose: To evaluate the morphologic substrate of the rim enhancement of colorectal metastases seen at CT during infusion hepatic arteriogra phy (CTIHA). Material and Methods: Eleven sector defects in the enhanc ing rim of 9 metastases at CTIHA were analyzed. The corresponding path ologic specimens were investigated for sector defects of liver parench yma. We investigated whether there was a correlation between the centr al angle of the sector defects of rim enhancement at CTIHA and that of sector defects in the zone of liver parenchyma in histologic slices. The inner and outer diameters of the enhancing rim were also compared with the diameter of the metastases as seen at CT during arterial port ography (CTAP). Results: There was a significant correlation between t he central angle of sector defects of rim enhancement at CTIHA and the angle of sector defects in the zone of liver parenchyma in histologic slices (p=0.008, Spearman's test). The diameter of the metastases mea sured at CTAP was larger than the inner diameter and smaller than the outer diameter of the enhancing rim in CTIHA, i.e. the margins of the nodules as seen in CTAP are located in liver parenchyma and not in tum or tissue. Conclusion: The morphologic substrate of the rim enhancemen t of colorectal metastases seen at CTIHA is liver parenchyma.