Name : Hanid Reza
Family : Pouraliakbar
Affiliation :Radiology Department, Shahied Rajaie Cardiovascular Medical Center,TUMS
Academic Degree : Assistant Professor of Radiology
Resident : Mehran Mansouri
Gender : Male
Age : 66
66 years old man with history of CABG and abdominal pain.
Axial CT angiography images shows thrombosis within midpart of SMA and luminal narrowing and wall thickening near the splenic flexure (red arrow), the "watershed" area between the vascular distribution of the SMA and IMA. Note the aorta atherosclerotic changes with luminal thrombosis.
Discussion (Related Text)
Occlusive intestinal ischemia is usually caused by either arterial or venous disease, although arterial occlusion accounts for most cases. More than 95% of patients with embolic occlusion of the SMA have documented histories of cardiac disease, with the emboli usually originating from a left atrial or ventricular mural thrombus. The embolus lodges at points of normal anatomic narrowing immediately distal to the origin of a major arterial branch. Most patients with SMA thrombosis also have a history of coronary, cerebrovascular, or peripheral arterial insufficiency, and thrombosis occurs at points of severe atherosclerotic narrowing, most often at the origin of the SMA. Before symptoms are expected, the degree of arterial narrowing must be severe, with narrowing of the cross sectional area by 50% to 80%.174 In addition to the arterial luminal narrowing, systemic blood pressure and the degree of collateral circulation also play a role in determining the severity of a patient's symptoms and the extent of ischemic insult. If collateral circulation is adequate, bowel infarction may not develop even in cases with total occlusion of the main SMA or inferior mesenteric artery.
Haaga J: CT and MR imaging of the whole body, 5th ed. Philadelphia: Mosby, 2009.