PURPOSE: To document the findings of a small arterioportal(AP) shunt on hepatic angiography through the various diagnostic modalities, and to determine whether this shunt is related to hepatocelluar carcinoma. MATERIALS AND METHODS: During the hepatic angiography in 223 patients, a small AP shunt and subsequent focalparenchymal staining more than 1cm in diameter were found in 28 patients. We compared this angiographic abnormality using MR imaging(n=10), CTAP(n=12), iodized-oil CT(n=23), intraoperative ultrasonography(n=5) and follow-up hepatic angiography(n=11), as well as with conventional ultrasonography and CT scan. RESULTS: Arterioportal shunts noted on angiographic study matched with perfusion defects noted in CTAP(10/12) and also with the area of arterial enhancement seen on dynamic CT scan(3/4). In no case was a lesion found on MR and no Lipiodol uptake was seen on CT. There was no evidence of tumor growth around the AP shunts on follow-up angiographies, andno tumor was found during surgery. CONCLUSION: A small AP shunt was not related to the presence of a tumor. Ifthe hemodynamic changes resulfing from a small AP shunt are understood, confusion can be avoided in the interpretation of vascular imaging including CTAP and dynamic CT.