SERIAL CHANGES IN NUCLEAR MAGNETIC-RESONANCE RELAXATION-TIMES AFTER MYOCARDIAL-INFARCTION IN THE RABBIT - RELATIONSHIP TO WATER-CONTENT, SEVERITY OF ISCHEMIA, AND HISTOPATHOLOGY OVER A 6-MONTH PERIOD
SERIAL CHANGES IN NUCLEAR MAGNETIC-RESONANCE RELAXATION-TIMES AFTER MYOCARDIAL-INFARCTION IN THE RABBIT - RELATIONSHIP TO WATER-CONTENT, SEVERITY OF ISCHEMIA, AND HISTOPATHOLOGY OVER A 6-MONTH PERIOD
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DOI：
10.1002/mrm.1910080402
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发表时间：
1988-12-01
影响因子：
3.3
通讯作者：
OKADA, RD
中科院分区：
文献类型：
--
作者：
JOHNSTON, DL;HOMMA, S;OKADA, RD
为了确定心肌梗死T1和T2弛豫时间的系列变化，以及它们与所观察到的含水量、局部心肌血流量和组织病理学变化的关系，对家兔在冠状动脉结扎后30分钟至6个月的14个时间间隔进行了研究。将所有值与对照组进行比较。心脏被细分为梗死和正常段的血流量，水含量和弛豫时间（20 MHz光谱仪）的测量;其他心脏被切除完整的组织病理学研究。在6个月的研究期间，与对照组相比，梗死心肌的T1弛豫时间没有显著变化。T2弛豫时间在第3天增加（P < 0.0001），并在2个月时恢复至基线。与梗死的T2增加相一致，3天时的核磁共振（NMR）图像显示与周围正常心肌相比，梗死的信号强度增加。6个月时，观察到明显的心肌变薄，信号强度无变化。梗死心肌T2的变化与含水量或缺血严重程度的变化无关，但与组织病理学检测到的梗死愈合和瘢痕形成相关性最好。总之，这项研究的结果表明，T2弛豫时间的梗死心肌在3天显着增加，并保持2个月的升高。这些变化与梗死愈合的开始和进展最相关。这些数据证明了T2加权核磁共振成像在评估缺血性心肌损伤后的愈合模式方面的潜力。
To determine the serial changes in T1 and T2 relaxation times of myocardial infarction, and their relationship to observed changes in water content, regional myocardial blood flow, and histopathology, rabbits were studied at 14 time intervals ranging from 30 min to 6 months after coronary artery ligation. All values were compared to a control group. Hearts were subdivided into infarct and normal segments for measurements of blood flow, water content, and relaxation times (20-MHz spectrometer); other hearts were excised intact for histopathologic studies. T1 relaxation time of infarcted myocardium did not change significantly compared to control over the 6-month study period. T2 relaxation time increased (P < 0.0001) at 3 days and returned to baseline by 2 months. Consonant with the increase in T2 of infarct, nuclear magnetic resonance (NMR) images at 3 days demonstrated an increase in signal intensity of infarct compared to surrounding normal myocardium. At 6 months, marked myocardial thinning was observed without changes in signal intensity. Changes in T2 of infarcted myocardium were not related to changes in water content or severity of ischemia, but correlated best with infarct healing and scar formation as detected on histopathology. In conclusion, the findings of this study indicate that T2 relaxation time of the infarcted myocardium increases markedly at 3 days and remains elevated for 2 months. These changes correlate best with the onset and progression of infarct healing. These data demonstrate the potential of T2-weighted NMR imaging for assessing healing patterns following ischemic myocardial injury.