Portal venous gas: detection by gray-scale and Doppler sonography in the absence of correlative findings on computed tomography.

Two cases are described in which portal venous gas (PVG) was detectable by ultrasound, but the liver appeared normal on computed tomography (CT). The finding of PVG was associated with ischemic bowel in one case but was a benign finding in the other case. The gray-scale and Doppler ultrasound findings associated with PVG are described. This case report illustrates two key points. First, ultrasound may detect gas within the portal venous system when CT is negative. Second, when PVG is detected on ultrasound, urgent clinical assessment followed by contrast-enhanced CT is indicated to assess for associated intestinal ischemia.