Pflugfelder P W, Wisenberg G, Prato F S, Turner K L, Carroll S E
J Am Coll Cardiol. 1986 Apr;7(4):843-9. doi: 10.1016/s0735-1097(86)80346-1.
Anterior infarction was produced in eight dogs to characterize serial changes in nuclear magnetic resonance signal intensity within the infarct zone. Magnetic resonance imaging was done on the day of infarction, on day 4, 5 or 6, on day 13 and day 20 using a 0.15 tesla (6.25 MHz) resistive imager. Electrocardiographically triggered spin echo (30, 45 and 60 ms echo times) and inversion recovery (400 to 500 ms inversion time) pulse sequences were employed to obtain single slice images. On day 20, the excised hearts were sectioned and examined to determine infarct location and extent. In the spin echo images, signal intensity within the ischemic zone was visibly increased in seven of the eight dogs on the day of infarction, and in all dogs by days 4 to 6. Signal intensity remained elevated in all but two dogs at day 20. With inversion recovery imaging, changes in the infarct zone were highly variable; both ill defined increases and decreases in signal intensity were noted. With a 30 ms echo time, signal intensity in the infarct zone was increased on average 29.8 +/- 24.1% above that in normal myocardium on the day of infarction. The relative signal intensity increased to 62.4 +/- 23.5% during the first 2 weeks after infarction (p less than 0.05), then decreased to 12.0 +/- 18.5% by day 20 (p less than 0.05). Similar changes were detected in the images using the 45 and 60 ms echo times. Nuclear magnetic resonance imaging therefore is able to detect regions of myocardial infarction and follow evolutionary changes in signal intensity within the infarct zone with healing.
对8只犬造成前壁梗死，以描述梗死区内核磁共振信号强度的系列变化。在梗死当天、第4、5或6天、第13天和第20天，使用0.15特斯拉（6.25兆赫）的电阻式成像仪进行磁共振成像。采用心电图触发自旋回波（回波时间30、45和60毫秒）和反转恢复（反转时间400至500毫秒）脉冲序列获取单层图像。在第20天，将切除的心脏切片并检查以确定梗死的位置和范围。在自旋回波图像中，8只犬中有7只在梗死当天缺血区内的信号强度明显增加，到第4至6天时所有犬的缺血区内信号强度均增加。除2只犬外，所有犬在第20天时信号强度仍保持升高。采用反转恢复成像时，梗死区内的变化差异很大；信号强度既有不明确的增加也有降低。在梗死当天，回波时间为30毫秒时，梗死区内的信号强度平均比正常心肌高出29.8±24.1%。梗死后头2周内相对信号强度增加到62.4±23.5%（p<0.05），到第20天时降至12.0±18.5%（p<0.05）。使用45和60毫秒回波时间的图像中也检测到类似变化。因此，核磁共振成像能够检测心肌梗死区域，并跟踪梗死区内信号强度随愈合过程的演变变化。
