Department of Radiology, Université Jean Monnet Saint-Etienne, CREATIS, UMR CNRS 5220-INSERM U1044, Lyon, France.
Radiology. 2012 Oct;265(1):12-22. doi: 10.1148/radiol.12111769.
The use of T2-weighted MR imaging to delineate the area at risk and subsequently quantify myocardial salvage is problematic on many levels. The validation studies available thus far are inadequate. Unlike the data validating DE MR imaging, in which pathologic analysis has shown the precise shape and contour of the bright region exactly match the infarcted area, this level of validation does not exist for T2-weighted MR imaging. Technical advances have occurred, but image contrast between abnormal and normal regions remains limited, and in this situation, measured size differences between MR imaging data sets should not be overinterpreted. Moreover, with any T2 technique, there remains the key issue that there is no physiologic basis for the apparent T2 findings. Indeed, a homogeneously bright area at risk on T2-weighted MR images is incompatible with the known levels of edema that occur in infarcted and salvaged myocardium, and the finding that the lateral borders of T2 hyperintense regions frequently extend far beyond that of infarction is contrary to the wavefront phenomenon. Even if T2-weighted MR imaging provided an accurate measure of myocardial edema, the level of edema within the area at risk is dependent on multiple variables, including infarct size, age, reperfusion status, reperfusion injury, and therapies that could have an antiedema effect. The area at risk is a coronary perfusion territory. There is a fundamental limitation with defining the area at risk by using a nonperfusion-based indicator that can vary with different postreperfusion therapies. There are several applications for T2 myocardial imaging, including differentiation of acute from chronic MI and identification of acute myocarditis. On the basis of the currently available data; however, we conclude that T2-weighted MR imaging should not be used to delineate the area at risk in patients with ischemic myocardial injury.
在许多方面，使用 T2 加权磁共振成像来描绘危险区域，并随后定量评估心肌挽救都是有问题的。到目前为止，可用的验证研究还不够充分。与验证 DE MR 成像的数据不同，病理分析显示，亮区的精确形状和轮廓与梗死区完全匹配，而对于 T2 加权磁共振成像，并不存在这种水平的验证。技术已经取得了进步，但异常和正常区域之间的图像对比度仍然有限，在这种情况下，不应过度解释磁共振成像数据集之间测量的大小差异。此外，对于任何 T2 技术，仍然存在一个关键问题，即 T2 表现没有生理基础。事实上，T2 加权磁共振图像上危险区域的均匀亮区与梗死和挽救心肌中发生的已知水肿水平是不兼容的，并且 T2 高信号区域的外侧边界经常远远超出梗死区域的发现与波前现象相矛盾。即使 T2 加权磁共振成像提供了心肌水肿的准确测量，危险区域内的水肿水平取决于多个变量，包括梗死大小、年龄、再灌注状态、再灌注损伤以及可能具有抗水肿作用的治疗方法。危险区域是一个冠状动脉灌注区域。使用基于非灌注的指标来定义危险区域存在根本限制，因为该指标可能因不同的再灌注治疗而变化。T2 心肌成像有多种应用，包括区分急性和慢性 MI 以及识别急性心肌炎。然而，根据目前可用的数据，我们得出结论，T2 加权磁共振成像不应用于描绘缺血性心肌损伤患者的危险区域。
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