Institute of Radiology, Second University of Naples, Naples, Italy.
J Biol Regul Homeost Agents. 2013 Jul-Sep;27(3):771-9.
To validate a rat model of acute arterial mesenteric ischemia correlating MRI patterns with macro and microscopic changes in the small bowel. Thirty Sprague-Dawley rats were assigned to two experimental groups (Group I and Group II) of fifteen rats each. Group I underwent surgical procedure of superior mesenteric artery (SMA) ligation, followed by macroscopic observation. In Group II, a loop was tied loosely around the SMA without occluding the vessel. Three days after surgery, the loop was tied by external tips to completely occlude the artery. 7T microMR (7Tesla microMR) was performed before and 8 hours after SMA occlusion. At predetermined time-points the histopathological examinations were performed in both of groups. Macroscopic monitoring revealed thinning of mesenteric vessels, hypotonic reflex ileus and chromatic change of some loops. 7T microMR sequences evidenced loop dilation with gas-fluid mixed stasis, intraperitoneal free fluid and bowel wall hyperintensity. There were no significant differences in the histological analysis between the two groups. The gap of three days from surgery, adopted in the Group 2, allowed to avoid signs of peritoneal and mesenteric irritation which could bias imaging patterns. MR succeeded to identify the signs of arterial mesenteric ischemia.
为了验证与 MRI 模式相关的急性肠系膜动脉缺血大鼠模型与小肠的宏观和微观变化。将 30 只 Sprague-Dawley 大鼠分为两组（实验组 I 和实验组 II），每组 15 只。实验组 I 接受肠系膜上动脉（SMA）结扎手术，然后进行宏观观察。实验组 II 中，SMA 周围轻轻系一环，但不阻塞血管。手术后 3 天，用外部尖端将环系紧以完全阻塞动脉。在 SMA 闭塞前和闭塞后 8 小时进行 7T 微磁共振成像（7Tesla microMR）。在两组均进行预定时间点的组织病理学检查。宏观监测显示肠系膜血管变薄、低张性反射性肠梗阻和一些肠环变色。7T 微磁共振成像序列显示肠环扩张，伴有气液混合停滞、腹腔游离液和肠壁高信号。两组之间的组织学分析无显著差异。在实验组 II 中，手术与评估之间的时间间隔为 3 天，这避免了腹膜和肠系膜刺激的迹象，这些迹象可能会影响成像模式。MR 成功地识别了肠系膜动脉缺血的迹象。
