Aneurysms of the portal venous system: ultrasonography and CT findings

The retrospective study of aneurysms of the portal venous system and their possible aetiology, using different imaging methods.

Between 1992 and 1995 we collected 13 cases of portal vein aneurysm from 11 patients, eight of whom suffered portal hypertension (PH) secondary to hepatic cirrhosis. All were diagnosed by means of ultrasonography (155) and/or computed tomography (CT). The aneurysms were defined as fusiform expansions when in the main portal vein and its branches or as cystic lesions with internal flow when in the intrahepatic branches.

Ten of the aneurysms (76.9%) were in the extrahepatic portal venous system and three (23.1%) in intrahepatic branches. Of the extrahepatic aneurysms, the two most common locations were the main portal vein and the confluence of superior mesenteric and splenic veins (30.7% each site). The largest were generally those at the confluence (37.6+/-9.7 mm maximum diameter).

Aneurysms in the portal system can be congenital or acquired. Although their aetiology is uncertain, we found a clear relation to PH syndrome; of 13 aneurysms in the study, eight were related to this disease. PH should be suspected in the evaluation of portal aneurysms.