Similarly to CT with IV contrast, oral contrast administration may delay the examination if it is routinely performed. CT without and with IV contrast is not indicated in the evaluation of suspected acute mesenteric ischemia. MRA Abdomen and Pelvis Magnetic resonance angiography (MRA) of the abdomen and pelvis with IV contrast has high sensitivity and specificity for diagnosing severe stenosis or occlusion at the origins of the celiac axis and SMA [44-47]. However, it has a limited role in diagnosing distal stenosis as well as nonocclusive mesenteric ischemia, and its use may delay therapeutic options in acute settings because it is a long examination. MRA is tailored to depict mesenteric vasculature and less likely to show ischemic findings within the bowel itself compared to CT, such as pneumatosis and portovenous gas; it is also unlikely to provide additional information in the acute setting if portal venous phase CT has already been performed [48]. MRA without contrast can be attempted in some cases; however, evaluation of smaller vessels may be suboptimal [46]. In the past decade with the advances in technology, CTA supplanted conventional angiography as the first-line imaging technique for acute mesenteric ischemia, and angiography transitioned to complementary diagnostic role with an option of endovascular treatment for revascularization candidates [57-62]. Although there is a lack of Level I evidence demonstrating clear benefits of endovascular therapy compared to open surgery in patients with acute mesenteric ischemia, the available data from systematic reviews and case series show that the endovascular approach is becoming more common and is associated with decreased mortality and need for laparotomy [57-62]. Nonetheless, acute mesenteric ischemia is a vascular surgical emergency requiring immediate surgical evaluation and angiography should not be considered in patients with significant hypovolemia or hypotension.
Imaging of Mesenteric Ischemia. Similarly to CT with IV contrast, oral contrast administration may delay the examination if it is routinely performed. CT without and with IV contrast is not indicated in the evaluation of suspected acute mesenteric ischemia. MRA Abdomen and Pelvis Magnetic resonance angiography (MRA) of the abdomen and pelvis with IV contrast has high sensitivity and specificity for diagnosing severe stenosis or occlusion at the origins of the celiac axis and SMA [44-47]. However, it has a limited role in diagnosing distal stenosis as well as nonocclusive mesenteric ischemia, and its use may delay therapeutic options in acute settings because it is a long examination. MRA is tailored to depict mesenteric vasculature and less likely to show ischemic findings within the bowel itself compared to CT, such as pneumatosis and portovenous gas; it is also unlikely to provide additional information in the acute setting if portal venous phase CT has already been performed [48]. MRA without contrast can be attempted in some cases; however, evaluation of smaller vessels may be suboptimal [46]. In the past decade with the advances in technology, CTA supplanted conventional angiography as the first-line imaging technique for acute mesenteric ischemia, and angiography transitioned to complementary diagnostic role with an option of endovascular treatment for revascularization candidates [57-62]. Although there is a lack of Level I evidence demonstrating clear benefits of endovascular therapy compared to open surgery in patients with acute mesenteric ischemia, the available data from systematic reviews and case series show that the endovascular approach is becoming more common and is associated with decreased mortality and need for laparotomy [57-62]. Nonetheless, acute mesenteric ischemia is a vascular surgical emergency requiring immediate surgical evaluation and angiography should not be considered in patients with significant hypovolemia or hypotension.