Imaging description

Traditional CT signs of acute mesenteric ischemia such as visceral artery occlusion, pneumatosis, portomesenteric venous gas, and bowel wall thickening are generally derived from surgically proven series [1,2]. This is scientifically rigorous but does not account for the fact that many patients with presumed thromboembolic mesenteric ischemia do not go to surgery, and are characterized by milder degrees of self-limiting segmental bowel dilatation, bowel wall thickening, mesenteric infiltration, and ascites (Figures 57.1–57.4) [3, 4]. The emerging concept that acute mesenteric ischemia covers a clinicoradiological spectrum varying from mild and self-limiting to severe and life-threatening [3] is analogous to the spectrum of neurological deficits due to cerebrovascular insufficiency varying from transient ischemic attack to full-blown stroke. The term “transient ischemia of the bowel” has reasonably been proposed to describe those with the milder forms of acute mesenteric ischemia.

Importance

It is likely that transient ischemia of the bowel is underrecognized. In one series, 8 of 30 patients with acute abdominal pain and atrial fibrillation had CT signs of end-organ ischemia or infarction [3]. Atrial fibrillation affects an estimated 2.3 million Americans [5], so the population at risk is substantial. Failure to recognize the diagnosis may result in a missed opportunity for reassessment of anticoagulation status.