Angelos M G, Katz-Stein A, Leasure J E
Department of Emergency Medicine, Wright State University, Cox Institute, Kettering, Ohio.
Ann Emerg Med. 1993 Sep;22(9):1378-84. doi: 10.1016/s0196-0644(05)81982-1.
To determine the effectiveness of magnetic resonance imaging in detecting early myocardial infarction in vivo after coronary artery occlusion.
A prospective, controlled canine study using a left anterior descending coronary artery ligation model.
After thiopental anesthesia, nine mongrel dogs underwent cardiac-gated magnetic resonance imaging with a 2.35-T magnet with a 40-cm bore before and four hours after ligation of the left anterior descending coronary artery.
Hemodynamic and left ventricular blood flow changes were determined. The mean image intensity ratio of the suspected infarct region to the normal myocardium was determined in the four-hour postocclusion images and compared with the ratio from the same anatomic region obtained at baseline. The area of necrotic and ischemic myocardium was determined using fluorescein and triphenyl tetrazolium chloride staining immediately after four-hour images. All animals were noted to have necrotic (range, 1.8% to 20.4% of ventricles) and ischemic (range, 9.2% to 36.6% of ventricles) myocardium with histochemical staining. The mean intensity ratio of infarcted myocardium four hours after left anterior descending coronary artery occlusion was significantly higher than baseline (four hours, 2.31 +/- 0.82; baseline, 1.02 +/- 0.09; P < .002).
Magnetic resonance imaging can distinguish myocardial edema associated with acute infarcting myocardium in vivo as early as four hours after left anterior descending coronary artery occlusion. Magnetic resonance imaging may be clinically useful in identifying thrombolytic therapy candidates among acute myocardial infarction patients presenting with atypical symptoms.
确定磁共振成像在检测冠状动脉闭塞后体内早期心肌梗死方面的有效性。
一项前瞻性对照犬类研究，采用左前降支冠状动脉结扎模型。
在硫喷妥钠麻醉后，9只杂种犬在左前降支冠状动脉结扎前和结扎后4小时，使用孔径为40厘米的2.35-T磁体进行心脏门控磁共振成像。
测定血流动力学和左心室血流变化。在闭塞后4小时的图像中测定疑似梗死区域与正常心肌的平均图像强度比，并与基线时在相同解剖区域获得的比值进行比较。在4小时图像采集后立即使用荧光素和氯化三苯基四氮唑染色确定坏死和缺血心肌的面积。通过组织化学染色发现所有动物均有坏死（范围为心室的1.8%至20.4%）和缺血（范围为心室的9.2%至36.6%）心肌。左前降支冠状动脉闭塞4小时后梗死心肌的平均强度比显著高于基线（4小时时为2.31±0.82；基线时为1.02±0.09；P<.002）。
磁共振成像能够在左前降支冠状动脉闭塞后4小时就区分出体内与急性梗死心肌相关的心肌水肿。磁共振成像在识别表现为非典型症状的急性心肌梗死患者中的溶栓治疗候选者方面可能具有临床应用价值。
