Evaluation of suspected mesenteric ischemia efficacy of radiologic studies

Mesenteric ischemia is a common disorder that is increasing in incidence as the overall population ages. About 0.1% of all patients referred to a hospital and 1% of patients with acute abdomen have mesenteric ischemia [1-3]. Mesenteric ischemia or infarction occurs in a variety of conditions resulting in interruption or reduction of the blood supply of the intestine. This may be acute or chronic depending on the onset and clinical presentation. Classically, mesenteric ischemia or infarction can be categorized as occlusive or nonocclusive, according to the presence or absence of vascular occlusion [4]. In addition to the major causative factors, such as thromboembolism or hypovolemia, many underlying causes including bowel obstruction, vasculitis, neoplasm, trauma, and iatrogenic causes, such as drug or radiation therapy, may contribute to mesenteric ischemia. Irrespective of the cause of the ischemic insult, however, the end results are similar and range from transient alteration of bowel activity to transmural hemorrhagic necrosis. In the circumstance with suspected mesenteric ischemia, early diagnosis is crucial because critical intestinal ischemia progresses to fatal infarction unless promptly diagnosed and treated. Despite advances in medical knowledge and patient management, the morbidity and mortality of mesenteric ischemia have remained high over the past 30 years [4-6]. Mortality rates in acute mesenteric ischemia exceed 60%. This is caused in part by the lack of an optimal diagnostic imaging tool. In most cases, clinical presentations and plain radiographic findings are nonspecific and give little clue to the specific diagnosis, especially early in the course of the disease. In the past, radiologic studies including CT have allowed only limited success in early detection of mesenteric ischemia. With remarkable technical advances, however, the role of CT has conspicuously increased in evaluating patients with acute abdominal symptoms. Because of capacity of demonstrating vascular or intestinal changes and other ancillary abdominal features, CT is considered the procedure of choice when intestinal infarction is suspected on clinical grounds. Similar to CT, the use of MR imaging has been assessed by several investigators. They have recently reported that MR imaging may be comparable with CT for demonstrating the bowel wall changes and mesenteric vascular abnormalities associated with intestinal ischemia [7,8]. This article reviews the efficacy of radiologic studies for evaluating patients with suspected mesenteric ischemia, both in terms of diagnostic radiologic features and pathophysiology of mesenteric ischemia resulting from various underlying causes.