犬急性心肌梗死与再灌注的多层螺旋CT评价实验研究

目的探讨多层螺旋CT评价急性冠状动脉闭塞后心肌梗死及再灌注的能力.方法将12只杂种犬随机分成两组:①急性心肌梗死组(AMI),分别于结扎冠状动脉前、结扎后1 h和2 h进行CT平扫和增强扫描.②AMI再灌注组,分别于结扎前、结扎后1 h及再灌注30 min进行同样扫描.观察心肌梗死的病变部位及形态,测量每组正常心肌、心肌梗死部位在各个扫描时点的CT值,计算两者与左心室腔的CT值之比(M/L).结果12只犬结扎左前降支后1 h增强图像上左心室前壁或心尖区均有明显的低密度区形成.AMI组结扎后2 h图像缺血区的密度更为减低;AMI再灌注组再灌注30 min后病变的密度变化不明显.AMI组结扎后1 h与2 h的正常心肌与梗死心肌的CT值均值及两者与左心室腔的M/L均具有显著性差异(P＜0.001).AMI再灌注组结扎后1 h与再灌注后30 min正常心肌与梗死心肌的CT值均值及两者与左心室腔M/L也具有显著性差异(P＜0.001).结论急性冠脉闭塞后心肌梗死区MSCT表现为低密度,MSCT能够区分急性冠状动脉闭塞后梗死心肌与正常心肌.

Evaluation of acute myocardial infarction and reperfusion with multi-slice spiral CT in dogs: experimental study

Objective To evaluate acute myocardial infarction and reperfusion after obstruction of coronary artery with 16-slice spiral CT by animal model. Methods Twelve hybrid canines were divided into two groups. The pre-enhanced CT and contrast-enhanced CT at one and two hours after ligation of left anterior descending artery (LAD) were performed in acute myocardial infarction group (AMI), respectively. The same CT scanning at one hour after ligation of LAD and 30 min after reperfusion was also performed in AMI reperfusion group, respectively. The morphological features of ischemic myocardium were observed. The CT values of normal and ischemic myocardium were measured. The M/L ratios of the CT value of normal and infarction myocardium to that of left ventricle cavity were calculated. Results The infarction areas of all 12 hybrids showed low density at one hour after ligation of LAD. The density of infarction area was much lower at 2 hours after ligation of vessel in AMI group. In AMI reperfusion group, the density of lesion area did not obviously change after 30 mins reperfusion. For AMI group, significant differences of the CT values and the M/L ratios at one or two hours after ligation of LAD existed (P<0.001). For AMI reperfusion group, significant differences of the values above mentioned also existed at one hour after ligation and 30mins after reperfusion (P<0.001). Conclusion Acute myocardial infarction area showed low density on the contrast-enhanced CT image. MSCT can distinguish the infarction myocardium and normal area.