Portomesenteric venous gas: imaging findings with an emphasis on sonography.

OBJECTIVE: Portomesenteric venous gas is a rare condition with an unclear pathogenesis. Most studies in the medical literature mention computed tomography (CT) as the primary imaging tool for this entity. The objective of this study was to outline the advantages and disadvantages of sonography in the evaluation of patients with portomesenteric venous gas. METHODS: We describe 7 patients (3 female and 4 male; age range, 47-83 years) with portomesenteric venous gas. Both CT and sonographic examinations were performed in each patient. Our patient population consisted of 2 patients with superior mesenteric artery occlusion, 3 with ischemia of the colon, small bowel, or both, 1 with gastric ulcer perforation, and 1 with ischemic bowel disease presumably secondary to complications of continuous ambulatory peritoneal dialysis. RESULTS: Portal venous gas was observed in all 7 patients with sonography and in 6 patients with CT. Computed tomography was unable to show gas in the portal venous system in 1 patient. Sonography showed patchy hepatic gas accumulation (likely within small peripheral portal vein branches) with no correlative findings on CT. Computed tomography showed important associated findings, including pneumatosis intestinalis. CONCLUSIONS: In cases with portomesenteric gas, CT is the preferred modality for showing the underlying etiology. However, with its real-time imaging capability, sonography may also be a very valuable imaging modality in the evaluation of this entity.