Ko G Y, Ha H K, Lee H J, Jeong Y K, Kim P N, Lee M G, Kim H R, Yang S K, Auh Y H
Department of Diagnostic Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
AJR Am J Roentgenol. 1997 Apr;168(4):951-6. doi: 10.2214/ajr.168.4.9124147.
The purpose of this study was to assess the usefulness of CT scans for distinguishing ischemic from tumoral segments in patients with colonic carcinoma complicated by proximal bowel ischemia.
CT scans of 20 patients with ischemic colitis proximal to obstructing colonic carcinoma were reviewed retrospectively. The concomitant presence of ischemia was proven on pathologic examinations in 12 patients and on barium enema studies in the remaining eight patients. CT scans were analyzed for the involved site and length, bowel wall thickness, enhancing pattern of both tumoral and ischemic segments, and changes in the pericolic space. The results of tumor staging on CT scans were compared with those of pathologic findings.
Distinction of ischemic from tumoral segments could be made on CT in 15 (75%) of the 20 patients. Of the 20 patients, 18 had ischemic segments contiguously proximal to the tumoral segment, and the remaining two patients had a skipped zone with intervening normal mucosa. Tumoral segments were irregularly thickened in most patients. Maximum thickness ranged from 0.8 to 4.5 cm (mean, 2.0 cm). Most often the ischemic segment was concentrically and smoothly thickened, ranging from 0.6 to 1.5 cm (mean, 1.0 cm). The tumoral segments enhanced heterogeneously in 12 patients and enhanced homogeneously in the remaining eight, whereas ischemic segments enhanced homogeneously in 14 (70%) patients and heterogeneously in six. On CT scans, we saw the target or double halo sign in four (20%) patients. Pericolic vascular engorgement was 19 patients, two of whom were overstaged because pericolic vascular engorgement was interpreted as tumor infiltration.
Although CT findings are not specific for certain groups of patients, they are often helpful in distinguishing tumoral from ischemic segments in patients with ischemic colitis proximal to colonic carcinoma. An understanding of this pathologic entity may increase the accuracy of CT for staging colonic carcinoma.
本研究旨在评估CT扫描在鉴别合并近端肠缺血的结肠癌患者中缺血段与肿瘤段的实用性。
回顾性分析20例梗阻性结肠癌近端缺血性结肠炎患者的CT扫描图像。12例患者经病理检查证实存在缺血，其余8例经钡剂灌肠检查证实。分析CT扫描图像中受累部位及长度、肠壁厚度、肿瘤段和缺血段的强化方式以及结肠周围间隙的变化。将CT扫描的肿瘤分期结果与病理结果进行比较。
20例患者中，15例（75%）可在CT上区分缺血段与肿瘤段。20例患者中，18例缺血段紧邻肿瘤段近端，其余2例患者有正常黏膜间隔的跳跃区。大多数患者的肿瘤段不规则增厚。最大厚度为0.8至4.5厘米（平均2.0厘米）。缺血段大多呈同心性、均匀增厚，范围为0.6至1.5厘米（平均1.0厘米）。12例患者的肿瘤段呈不均匀强化，其余8例呈均匀强化；14例（70%）缺血段呈均匀强化，6例呈不均匀强化。在CT扫描中，4例（20%）患者可见靶征或双晕征。19例患者有结肠周围血管充血，其中2例分期过高，因为结肠周围血管充血被误诊为肿瘤浸润。
虽然CT表现对某些患者群体不具有特异性，但在鉴别结肠癌近端缺血性结肠炎患者的肿瘤段与缺血段时通常很有帮助。了解这一病理实体可能会提高CT对结肠癌分期的准确性。
