Lauerma K, Saeed M, Wendland M F, Derugin N, Yu K K, Higgins C B
Department of Radiology, University of California, San Francisco 94143-0628, USA.
Am Heart J. 1996 Jan;131(1):14-23. doi: 10.1016/s0002-8703(96)90045-9.
Contrast-enhanced magnetic resonance (MR) imaging was used to detect and quantify the extent of myocardial injury after a brief coronary occlusion and reperfusion in response to verapamil treatment in a rat model of left ventricular hypertrophy (LVH). Two groups of rats were prepared by banding the abdominal aorta for 7 to 8 weeks to produce LVH. Group 1 (n = 13) received oral verapamil for 3 days, whereas group 2 (n = 13) received no therapy. Before MR examination was performed, each rat was subjected to 25 min of coronary artery occlusion followed by 1 hour of reperfusion. T1-weighted spin echo images were acquired before and after 0.3 mmol/kg gadoteridol was injected. Three images were acquired at contiguous levels of the LV and used to estimate the size of the myocardial injury. The size of the infarcted region was demarcated at postmortem examination by using triphenyltetrazolium chloride dye (TTC). Before contrast medium was administered, no significant difference in signal intensity was seen between nonischemic and reperfused ischemically injured myocardium. After gadoteridol was injected, a hyperintense zone indicative of myocardial injury was observed in 8 of 13 rats treated with verapamil and in all untreated animals. The size of the injury was significantly larger in untreated hearts than in hearts treated with verapamil as defined on MR images (25% +/- 5% vs 18% +/- 5%, p < 0.05) and TTC staining (12% +/- 4% and 4% +/- 1%, p < 0.05). Good correlation (r = 0.91) was found between the two measurements. No significant difference in the size of jeopardy area was seen between the two groups as (defined by blue dye infusion). In conclusion, contrast-enhanced MR imaging is a suitable technique to evaluate the effects of therapies applied to reduce myocardial injury. Verapamil can cause reduction in the extent of ischemic injury after reperfusion of hypertrophied myocardium.
在左心室肥厚（LVH）大鼠模型中，采用对比增强磁共振（MR）成像来检测和量化短暂冠状动脉闭塞及再灌注后心肌损伤的程度，以评估维拉帕米治疗的效果。通过结扎腹主动脉7至8周制备两组大鼠以产生LVH。第1组（n = 13）口服维拉帕米3天，而第2组（n = 13）未接受治疗。在进行MR检查前，每只大鼠经历25分钟的冠状动脉闭塞，随后再灌注1小时。在注射0.3 mmol/kg钆特醇前后采集T1加权自旋回波图像。在左心室连续层面采集三张图像，用于估计心肌损伤的大小。在尸检时用氯化三苯基四氮唑染料（TTC）划定梗死区域的大小。在给予造影剂前，非缺血心肌和再灌注缺血损伤心肌之间的信号强度无显著差异。注射钆特醇后，在13只接受维拉帕米治疗的大鼠中有8只以及所有未治疗的动物中观察到指示心肌损伤的高强度区。根据MR图像（25%±5%对18%±5%，p<0.05）和TTC染色（12%±4%和4%±1%，p<0.05）定义，未治疗心脏的损伤大小显著大于接受维拉帕米治疗的心脏。两种测量方法之间发现良好的相关性（r = 0.91）。两组之间危险区域的大小无显著差异（通过蓝色染料注入定义）。总之，对比增强MR成像是评估用于减少心肌损伤的治疗效果的合适技术。维拉帕米可使肥厚心肌再灌注后的缺血损伤程度降低。
