Intramyocardial hemorrhage (IMH) within myocardial infarction (MI) is associated with major adverse cardiovascular events. Bright-blood T2*-based cardiovascular magnetic resonance (CMR) has emerged as the reference standard for non-invasive IMH detection. Despite this, the dark-blood T2*-based CMR is becoming interchangeably used with bright-blood T2*-weighted CMR in both clinical and preclinical settings for IMH detection. To date however, the relative merits of dark-blood T2*-weighted with respect to bright-blood T2*-weighted CMR for IMH characterization has not been studied. We investigated the diagnostic capacity of dark-blood T2*-weighted CMR against bright-blood T2*-weighted CMR for IMH characterization in clinical and preclinical settings. Hemorrhagic MI patients (n = 20) and canines (n = 11) were imaged in the acute and chronic phases at 1.5 and 3 T with dark- and bright-blood T2*-weighted CMR. Imaging characteristics (Relative signal-to-noise (SNR), Relative contrast-to-noise (CNR), IMH Extent) and diagnostic performance (sensitivity, specificity, accuracy, area-under-the-curve, and inter-observer variability) of dark-blood T2*-weighted CMR for IMH characterization were assessed relative to bright-blood T2*-weighted CMR. At both clinical and preclinical settings, compared to bright-blood T2*-weighted CMR, dark-blood T2*-weighted images had significantly lower SNR, CNR and reduced IMH extent (all p < 0.05). Dark-blood T2*-weighted CMR also demonstrated weaker sensitivity, specificity, accuracy, and inter-observer variability compared to bright-blood T2*-weighted CMR (all p < 0.05). These observations were consistent across infarct age and imaging field strengths. While IMH can be visible on dark-blood T2*-weighted CMR, the overall conspicuity of IMH is significantly reduced compared to that observed in bright-blood T2*-weighted images, across infarct age in clinical and preclinical settings at 1.5 and 3 T. Hence, bright-blood T2*-weighted CMR would be preferable for clinical use since dark-blood T2*-weighted CMR carries the potential to misclassify hemorrhagic MIs as non-hemorrhagic MIs.

中文翻译：

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用暗血 T2* 加权心血管磁共振评估心肌内出血

心肌梗死 (MI) 内的心肌内出血 (IMH) 与主要的不良心血管事件有关。基于亮血 T2* 的心血管磁共振 (CMR) 已成为无创 IMH 检测的参考标准。尽管如此，在 IMH 检测的临床和临床前环境中，基于暗血 T2* 的 CMR 正变得与亮血 T2* 加权 CMR 互换使用。然而，迄今为止，尚未研究暗血 T2* 加权相对于亮血 T2* 加权 CMR 用于 IMH 表征的相对优点。我们在临床和临床前环境中研究了暗血 T2* 加权 CMR 与亮血 T2* 加权 CMR 对 IMH 表征的诊断能力。出血性 MI 患者 (n = 20) 和犬科动物 (n = 11) 在 1 的急性和慢性期成像。5 和 3 T，带有暗血和亮血 T2* 加权 CMR。成像特征（相对信噪比 (SNR)、相对噪声对比 (CNR)、IMH 范围）和诊断性能（敏感性、特异性、准确性、曲线下面积和观察者间变异性）相对于亮血 T2* 加权 CMR，评估了用于 IMH 表征的暗血 T2* 加权 CMR。在临床和临床前环境中，与亮血 T2* 加权 CMR 相比，暗血 T2* 加权图像的 SNR、CNR 和 IMH 范围显着降低（所有 p < 0.05）。与亮血 T2* 加权 CMR 相比，暗血 T2* 加权 CMR 还表现出较弱的敏感性、特异性、准确性和观察者间变异性（所有 p < 0.05）。这些观察结果在梗死年龄和成像场强方面是一致的。