Acute Mesenteric Ischemia: Anatomy, Imaging Techniques, and Pathophysiology

Acute mesenteric ischemia is frequently a rapidly life-threatening condition in which the radiologist may play a crucial role in early diagnosis and thus improve patient outcome. The small and large bowels are supplied by the celiac trunk, superior mesenteric artery, and inferior mesenteric artery with watershed zones at the splenic flexure (Griffith's point) and rectosigmoid junction (Sudeck's point). Important bowel collateral circulation is the superior-inferior pancreaticoduodenal anastomosis, marginal artery of Drummond, and arc of Riolan. The most common cause of acute mesenteric ischemia is arterial embolism or thrombosis with less common causes being veno-occlusive and other nonocclusive causes. CT angiography evaluation is the first-line modality with high sensitivity and specificity for identifying acute mesenteric ischemia. Dual-energy CT is an emerging modality, which may be helpful in subtle cases.