Diagnosis of Acute Bowel Ischaemia: Which Computed Tomography Finding Should We Trust?
VYK To, WL Poon, CY Lee, WS Wan
Hong Kong J Radiol 2014;17:234-9
DOI: 10.12809/hkjr1414240
Objective: To determine which computed tomography (CT) findings correlate most with acute bowel ischaemia.
Methods: This cross-sectional study included patients attending the Tuen Mun Hospital, Hong Kong between July 2005 and July 2011 who fulfilled one of the following criteria: (1) had undergone CT abdomen for clinical suspicion of bowel ischaemia, (2) CT showed evidence of bowel ischaemia with or without clinical suspicion, or (3) had operative findings of bowel ischaemia and had undergone CT previously. All CT images were reviewed independently by three radiologists who were blinded to the clinical outcome. Six specific CT findings including mural thickness, bowel dilatation, mural enhancement, pneumatosis intestinalis, portal or mesenteric venous gas, and superior mesenteric artery or venous (SMA/SMV) occlusion were documented. Binary logistic regression and adjusted odds ratio were used for statistical analysis. Intraclass correlation coefficient was calculated to determine the interobserver agreement among the three radiologists. The sensitivity, specificity, and positive predictive values were determined.
Results: A total of 148 patients were included, of whom 28 were excluded due to death without confirmed operative findings within the same admission. The remaining 120 patients were included for review. A combined feature of bowel dilatation with mural thinning was found to be the strongest CT indicator of acute bowel ischaemia with an odds ratio of 30.3 (p < 0.001; sensitivity, 73%; specificity, 94%; positive predictive value, 88%). The other significant CT indicator was mural hypoenhancement with an odds ratio of 6.3 (p = 0.001; sensitivity, 63%; specificity, 80%; positive predictive value, 68%). The intraclass correlation coefficient was 0.85 (p < 0.001), indicating a high degree of interobserver agreement in assessing the CT signs of acute bowel ischaemia.
Conclusion: A combined feature of dilatation with mural thinning and mural hypoenhancement are the strongest indicators for diagnosing acute bowel ischaemia.
中文摘要
急性腸缺血的診斷：應相信哪些CT徵象？
杜婉筠、潘偉麟、李芷茵、溫詠雪
目的：確定哪些電腦斷層掃描（CT）徵象與急性腸道缺血最為相關。
方法：本橫斷面研究包括2005年7月至2011年7月期間到香港屯門醫院求診並符合以下其中一項標準的病人：（1）因臨床懷疑腸道缺血而接受腹部CT掃描；（2）不論是否臨床懷疑，CT徵象提示腸道缺血；或（3）手術發現腸道缺血，並有腹部CT掃描記錄。所有CT圖像分別由三名放射科醫生在未知臨床結果的情況下獨立審閱然後記錄以下六項CT徵象：腸壁的厚度、腸道擴張、腸壁強化、腸壁內積氣、門靜脈或腸系膜靜脈氣體，以及腸系膜上動脈或靜脈（SMA/SMV）閉塞。利用二元logistic迴歸和校正比值比進行統計分析。計算組內相關係數以確定三名放射科醫生之間的觀察者間一致性。判定CT徵象的敏感性、特異性和陽性預測值。
結果：148個腸道缺血病例中，28個無該次入院的手術結果確診的死亡病例而不被列入研究範圍。餘下的120例列入回顧分析。結果發現腸道擴張伴有腸壁變薄為急性腸道缺血的最強CT診斷指標，其比值比為30.3（p < 0.001；敏感性73%、特異性94%、陽性預測值88%）。另一項指標為腸壁低強化，比值比為6.3（p = 0.001；敏感性63%、特異性80%、陽性預測值68%）。組內相關係數為0.85（p < 0.001），顯示三名放射科醫生在判斷急性腸道缺血的CT特徵具高度一致性。
結論：腸道擴張伴有腸壁變薄，以及腸壁低強化為診斷急性腸缺血的最強CT指標。