Tanabe K, Ishibashi Y, Shimada T, Tsukihashi H, Hatano J, Oyake N, Morioka S, Moriyama K, Sugimura K, Yuasa K
Fourth Department of Internal Medicine, Shimane Medical University, Izumo, Japan.
Jpn Circ J. 1993 May;57(5):458-66. doi: 10.1253/jcj.57.458.
In previous studies, magnetic resonance imaging (MRI) using contrast agents was found to be useful in distinguishing reperfused infarcts from nonreperfused infarcts. However, there have been only a few detailed studies using consecutive MR images for the assessment of myocardial reperfusion during an acute myocardial infarction and also no studies have been performed using a percutaneous transluminal coronary occlusion model (closed chest model). We induced acute myocardial infarction in dogs by occluding and then reperfusing the coronary artery with a balloon catheter. ECG-gated MR images were taken using the spin-echo technique before and after Gd-DTPA injection during both coronary artery occlusion and after reperfusion. We defined the intensity ratio (IR) as the signal intensity at the ischemic area divided by that at the nonischemic area on MR images and compared each image by the IR. Without Gd-DTPA, there was no difference between infarcted and normally perfused myocardium. Infarcted myocardium had a low signal intensity (IR = 0.68 +/- 0.14) soon after Gd-DTPA injection. This difference diminished with time. After reperfusion the infarcted myocardium had a high signal intensity (IR:1.76 +/- 0.34). We conclude that Gd-DTPA- enhanced MRI can distinguish reperfused from nonreperfused infarcts soon after Gd-DTPA administration.
在先前的研究中，发现使用造影剂的磁共振成像（MRI）有助于区分再灌注梗死灶与非再灌注梗死灶。然而，仅有少数详细研究使用连续的MR图像来评估急性心肌梗死期间的心肌再灌注，且尚未有研究使用经皮腔内冠状动脉闭塞模型（闭胸模型）进行。我们通过用球囊导管闭塞然后再灌注冠状动脉来诱导犬急性心肌梗死。在冠状动脉闭塞期间和再灌注后，使用自旋回波技术在注射钆喷酸葡胺（Gd-DTPA）前后采集心电图门控的MR图像。我们将强度比（IR）定义为MR图像上缺血区域的信号强度除以非缺血区域的信号强度，并通过IR比较每张图像。在未使用Gd-DTPA时，梗死心肌与正常灌注心肌之间无差异。注射Gd-DTPA后不久，梗死心肌的信号强度较低（IR = 0.68±0.14）。这种差异随时间减小。再灌注后，梗死心肌的信号强度较高（IR：1.76±0.34）。我们得出结论，Gd-DTPA增强的MRI在注射Gd-DTPA后不久可区分再灌注梗死灶与非再灌注梗死灶。
