CT Manifestations of Bowel Ischemia
Chung Kuao Chou
1 Department of Radiology, Chi Mei Foundation Hospital, 901 Chung Hwa Rd., Tainan 71010, Taiwan, Republic of China. Received April 9, 2001; accepted after revision July 11, 2001.
Bowel ischemia represents a process of insufficient blood supply of the small or large bowel with the consequences ranging from a transient, totally reversible attack to a lethally catastrophic event. This condition may result directly from arterial occlusion (thromboembolism of the superior mesenteric artery or its branches, vasculitis of various autoimmune diseases, and external compression of the artery by adhesion, volvulus, hernia, and intussusception), hypotension (congestive heart failure, hypovolemia, and sepsis), or vasoconstrictive medications (digitalis, norepinephrine, and ergotamine). Bowel ischemia may also be associated with impaired venous drainage (thrombosis of the mesenteric and portal veins, interference of intramural venous outflow by distention and elevated intraluminal pressure that occurs proximal to a stenotic lesion, and compression of the mesenteric veins by tumor, adhesion, volvulus, hernia, and intussusception) [1,2,3,4,5,6,7,8]. The severity of the ischemic attack depends on the acuteness, duration, degree, and state of the collateral circulation; extent of the involved area; and promptness in correcting the underlying pathologic process. The damage starts with the mucosa, which is most vulnerable to the ischemic insult, extends outward through the submucosa and the proper muscular layer, and ends at the serosa. The extent of the injury may range from mucosal, to mural, to transmural necrosis. We describe different conditions of the ischemic event and their corresponding CT appearances.