Brooks J P, Perry W B, Putnam A T, Karulf R E
Department of Colorectal Surgery, Wilford Hall Medical Center, San Antonio, Texas, USA.
Dis Colon Rectum. 2000 Sep;43(9):1319-21. doi: 10.1007/BF02237446.
The aim of this study was to introduce thermal imaging in the intraoperative detection of bowel ischemia by comparing thermal imaging with conventional techniques in detecting acutely ischemic bowel, using histologic evidence for intestinal necrosis as the standard.
A prospective study was performed using a porcine model. Laparotomy was performed on four pigs under general anesthesia. A 25-cm segment of mid jejunum was tagged with proximal and distal sutures, and its mesentery was ligated and divided. Thermal imaging, visual inspection, Doppler ultrasound, and fluorescence with Wood's lamp after fluorescein were used to estimate the extent of bowel ischemia five minutes after ligation of the mesentery. Measurements were taken in reference to both the proximal and distal tags to obtain two data points per animal for each method. After two hours of warm ischemia, the jejunum was harvested and sectioned longitudinally. Comparisons were made between the estimated region of necrosis for each method and microscopic evidence of necrosis.
Visual inspection was the only method unable to detect a difference between vascularized and devascularized bowel for each of the eight data points. Fluorescein dye missed 3 cm of ischemic bowel. Doppler ultrasound and thermal imaging were 100 percent sensitive for necrotic bowel, with thermal imaging overestimating necrosis to a greater extent than Doppler ultrasound. The positive predictive value of fluorescein dye, Doppler ultrasound, and thermal imaging for determining nonviable bowel was 91.8, 80.8, and 69.5 percent, respectively.
Thermal imaging has the potential to be a useful adjunct in the intraoperative determination of bowel ischemia. Further studies are indicated to study this technique.
本研究的目的是通过将热成像与传统技术在检测急性缺血性肠管方面进行比较，以组织学证据显示的肠坏死作为标准，来介绍热成像在术中检测肠缺血中的应用。
采用猪模型进行前瞻性研究。对4头猪在全身麻醉下进行剖腹手术。用近端和远端缝线标记一段25厘米长的空肠中段，结扎并切断其肠系膜。在结扎肠系膜5分钟后，使用热成像、目视检查、多普勒超声以及荧光素后用伍德灯进行荧光检查来评估肠缺血的程度。测量时参照近端和远端标记，每种方法每只动物获取两个数据点。经过两小时的热缺血后，取出空肠并纵向切片。比较每种方法估计的坏死区域与坏死的显微镜证据。
目视检查是唯一一种在八个数据点中的每一个都无法检测到血管化和非血管化肠管之间差异的方法。荧光素染料遗漏了3厘米的缺血肠管。多普勒超声和热成像对坏死肠管的敏感性均为100%，热成像比多普勒超声在更大程度上高估了坏死情况。荧光素染料、多普勒超声和热成像用于确定无活力肠管的阳性预测值分别为91.8%、80.8%和69.5%。
热成像有潜力成为术中确定肠缺血的有用辅助手段。需要进一步研究来探讨该技术。
