Imaging of Acute Mesenteric Ischemia Using Multidetector CT and CT Angiography in a Porcine Model

Abstract

Acute mesenteric ischemia, a frequently lethal disease, requires prompt diagnosis and intervention for favorable clinical outcomes. This goal remains elusive due, in part, to lack of a noninvasive and accurate imaging study. Traditional angiography is the diagnostic gold standard but is invasive and costly. Computed tomography (CT) is readily available and noninvasive but has shown variable success in diagnosing this disease. The faster scanning time of multidetector row CT (M.D.CT) greatly facilitates the use of CT angiography (CTA) in the clinical setting. We sought to determine whether M.D.CT-CTA could accurately demonstrate vascular anatomy and capture the earliest stages of mesenteric ischemia in a porcine model. Pigs underwent embolization of branches of the superior mesenteric artery, then imaging by M.D.CT-CTA with three-dimensional reconstruction protocols. After scanning, diseased bowel segments were surgically resected and pathologically examined. Multidetector row CT and CT angiography reliably defined normal and occluded mesenteric vessels in the pig. It detected early changes of ischemia including poor arterial enhancement and venous dilatation, which were seen in all ischemic animals. The radiographic findings-compared with pathologic diagnoses-predicted ischemia, with a positive predictive value of 92%. These results indicate that M.D.CT-CTA holds great promise for the early detection necessary for successful treatment of acute mesenteric ischemia. KeywordsMesenteric ischemia; computed tomography; angiography; animal model Acute mesenteric ischemia, the process of insufficient blood supply to the bowel, carries consequences ranging from a transient, totally reversible insult to a lethal event. The prevalence of mesenteric ischemia is increasing in the United States as the population ages. It is estimated that nearly 1% of patients presenting with acute abdominal pain have ischemic intestinal disease, 1-3 and it may be responsible for 0.1% of all hospital The lethality of the disease is well documented, with some series reporting mortality rates exceeding 60%. [4][5][6][7] A critical factor for survival of acute mesenteric ischemia is early diagnosis and intervention. In cases of superior mesenteric artery (SMA) embolism in which surgery is performed once the bowel is infarcted, the mortality rate nearly doubles from 35% to 68%. 8 The mean duration of ischemia preceding surgery for noninfarcted bowel is 13 hours, compared with 21 hours for those with infarction. 9 Thus, the window of opportunity for intervention is narrow and prompt diagnosis is crucial for patient survival. Nevertheless, this goal remains elusive, due in part to the lack of an accurate diagnostic imaging tool. NIH Public AccessAlthough angiography is considered the standard of reference for the diagnosis of mesenteric ischemia, it is not widely used because it is invasive, time-consuming, and costly. Computed tomography has been historically used with variable success for evaluating small bowel ischemia. It can help dete...

A Review of Scientific Topics and Literature in Abdominal Radiology in Germany – Part 1: Gastrointestinal Tract

“…A pictorial essay by Wildermuth et al [110] illustrates this very clearly. In an animal experiment with pigs, it was able to be shown that CTA can effectively differentiate between open and embolically occluded branches of the superior mesenteric artery with a positive predictive value of 92 % [111]. In a further study in which CT units with 16 rows or more were used, excellent sensitivity and specificity values for the diagnosis of arterial mesenteric ischemia were able to be achieved [112].…”

Mesenteric Ischemia: Results Of Surgical Treatment And A Review Of Literature

“…The severity of injury depends on etiology of ischemia, systemic blood pressure, collateral circulation flow, response of mesenteric vessels to autonomic stimulators, amounts of circulatory autonomic stimulators, regional hormonal factors, presence of cellular metabolites after reperfusion of the ischemic bowel, and duration of ischemia 2,7,11,12,17,23,24,25,26 Four pathologic factors have been described as the cause of acute mesenteric ischemia including: superior or inferior mesenteric artery emboli, thrombosis of these vessels, venous thrombosis, and non occlusive mesenteric ischemia 5,9,12,21 Emboli is the most common cause of AMI 1,14,15,25 Appropriate diagnosis of this disease depends on a high clinical suspicion particularly in elderly an patient who has history of cardiovascular disease 14,7,21,22 Early diagnosis and early intervention to ameliorate vascular obstruction are critical in patient's salvage 1,4,9,22,27 . Appropriate resuscitation of the patient and diagnostic studies and early surgical or non surgical intervention is the most effective approach to save the patient 1,3,9,28 .…”

Syndrome of Chronic Abdominal Ischemia in the Practice of General Surgeons

“…Основными инструметальными методами диагностики являются: ультразвуковое дуп лексное сканирование, спиральная компьютер ная томография (СКТ), магниторезонансная томография в режиме непрямой ангиографии (МРТ ангиография) и прямая ангиография [25,26,27]. Еще одним высокоинформатив ным, но, к сожалению, малодоступным в нашей стране методом диагностики СХАИ является эндоскопическое измерение напряжения PCO2 либо PO2 в слизистой оболочке желудка и ки шечника [28].…”

“…Однако он не дает возможности су дить о характере коллатерального кровотока и о состоянии нижней брыжеечной артерии из за малого ее диаметра. Данное исследование яв ляется скрининговым методом для отбора больных на ангиографию [26]. Высокой информативностью также облада ют неинвазивные современные методики иссле дования сосудов -СКТ и МРТ ангиография.…”

“…Высокой информативностью также облада ют неинвазивные современные методики иссле дования сосудов -СКТ и МРТ ангиография. Данные методы позволяют выявить не только окклюзию ВБА (до 92%), но и помогают в диф ференциальной диагностике таких заболеваний брюшной полости, как васкулиты и вазоспазм сосудов брыжейки тонкой кишки [26,27].…”