Describe the technique of biphasic CT scan and CT angiography (CTA) using multi-detetector row CT for the diagnosis of acute mesenteric ischemia (AMI). Describe the spectrum of CT signs seen in cases of acute bowel ischemia. Demonstrate the high sensitivity and specficity of biphasic CT with mesenteric CTA in the evaluation of AMI.

Eighteen (out of 43 evaluated) patients were found to have AMI using biphasic multidetector row CT. Mesenteric CTA was performed with 1.25 mm collimation starting 30 seconds after begining an IV injection of 120 ml of nonionic contrast agent at a rate of 3.5 ml/sec. This was followed by portal venous phase imaging (5 mm collimation) after a 60 seconds delay. CTA were reconstructed with multiplanar and volume-rendered techniques. The 25 patients without AMI were used as a control group for statistical analysis of positive CT signs. CTA depicted arterial disease in 4 patients and venous thrombosis in 6. The CT findings of any one of ; superior meseteric artery occlusion, pneumatosis intestinalis, venous gas was 100% specific and 65% sensitive. Other less specific signs were; venous thrombosis, bowel wall thickening with focal lack of bowel wall enhancement, bowel dilatation or ascites. Biphasic CT with mesenteric CTA is a highly sensitive and specific tool for the diagnosis of AMI.