Radiography findings in patients with acute mesenteric ischemia are usually nonspecific, late, and associated with a high mortality rate, as they often first appear when bowel infarction has already occurred [5,18-20]. A radiograph typically shows bowel dilatation in elderly patients and a gasless abdomen in younger patients with acute mesenteric ischemia [21]. Hepatic portal venous gas is a rare but important radiographic finding associated with several pathological processes, including bowel necrosis secondary to acute mesenteric ischemia. Portal venous gas can occur alone or in association with pneumatosis intestinalis. When associated with pneumatosis intestinalis, it usually indicates the presence of advanced mesenteric ischemia [18]. In addition, given its limited role in assessing for other causes of acute abdominal pain, radiographs in mesenteric ischemia should be solely utilized to screen for bowel perforation or obstruction [17]. All elements are essential: 1) timing, 2) reconstructions/reformats, and 3) 3-D renderings. Standard CTs with contrast also include timing issues and recons/reformats. Only in CTA, however, is 3-D rendering a required element. This corresponds to the definitions that the CMS has applied to the Current Procedural Terminology codes. CTA of the abdomen and pelvis is a fast, accurate, and noninvasive diagnostic tool for evaluating the bowel and assessing intestinal vasculature and should be the first-step imaging approach in patients with acute bowel ischemia [12,15,23-28]. CTA can be helpful in stratifying patients to identify those who would benefit from angiography as opposed to the ones who should undergo emergent surgery. Grading the degree of arterial stenosis with CTA has also been shown to be highly accurate compared to digital subtraction imaging (DSA) as well as other imaging modalities, including US and MRA [29].
Imaging of Mesenteric Ischemia. Radiography findings in patients with acute mesenteric ischemia are usually nonspecific, late, and associated with a high mortality rate, as they often first appear when bowel infarction has already occurred [5,18-20]. A radiograph typically shows bowel dilatation in elderly patients and a gasless abdomen in younger patients with acute mesenteric ischemia [21]. Hepatic portal venous gas is a rare but important radiographic finding associated with several pathological processes, including bowel necrosis secondary to acute mesenteric ischemia. Portal venous gas can occur alone or in association with pneumatosis intestinalis. When associated with pneumatosis intestinalis, it usually indicates the presence of advanced mesenteric ischemia [18]. In addition, given its limited role in assessing for other causes of acute abdominal pain, radiographs in mesenteric ischemia should be solely utilized to screen for bowel perforation or obstruction [17]. All elements are essential: 1) timing, 2) reconstructions/reformats, and 3) 3-D renderings. Standard CTs with contrast also include timing issues and recons/reformats. Only in CTA, however, is 3-D rendering a required element. This corresponds to the definitions that the CMS has applied to the Current Procedural Terminology codes. CTA of the abdomen and pelvis is a fast, accurate, and noninvasive diagnostic tool for evaluating the bowel and assessing intestinal vasculature and should be the first-step imaging approach in patients with acute bowel ischemia [12,15,23-28]. CTA can be helpful in stratifying patients to identify those who would benefit from angiography as opposed to the ones who should undergo emergent surgery. Grading the degree of arterial stenosis with CTA has also been shown to be highly accurate compared to digital subtraction imaging (DSA) as well as other imaging modalities, including US and MRA [29].