Purpose: The purpose of this work was to clarify the mechanism of peritumoral rim enhancement of metastatic liver cancer.
Method: Twenty-nine liver metastases of colon cancer were examined by single-level dynamic CT during hepatic arteriography, which was performed without table feed. We analyzed these findings and correlated them with the histopathologic findings.
Results: Eleven metastases were hypervascular and 18 were hypovascular. Early appearance of rim enhancement was seen in 3 of 10 hypervascular metastases and 17 of 18 hypovascular metastases (p < 0.01). The time of appearance and thickness of peritumoral rim enhancement showed no apparent correlation with the desmoplastic reaction or inflammation in the surrounding hepatic parenchyma.
Conclusion: Two types of intra- and peritumoral enhancement were observed. Peritumoral rim enhancement was considered to be due mainly to the drainage of blood flow from the tumor to the surrounding hepatic parenchyma in hypervascular metastasis or increased arterioportal shunts surrounding the tumor in hypovascular metastasis.