BACKGROUND Myocardial edema in acute myocardial infarction (AMI) is commonly imaged using dark-blood short tau inversion recovery turbo spin echo (STIR-TSE) cardiovascular magnetic resonance (CMR). The technique is sensitive to cardiac motion and coil sensitivity variation, leading to myocardial signal nonuniformity and impeding reliable depiction of edematous tissues. T2-prepared balanced steady state free precession (T2p-bSSFP) imaging has been proposed, but its contrast is low, and averaging is commonly needed. T2 mapping is useful but requires a long scan time and breathholding. We propose here a single-shot magnetization prepared sequence that increases the contrast between edema and normal myocardium and apply it to myocardial edema imaging. METHODS A magnetization preparation module (T2STIR) is designed to exploit the simultaneous elevation of T1 and T2 in edema to improve the depiction of edematous myocardium. The module tips magnetization down to the -z axis after T2 preparation. Transverse magnetization is sampled at the fat null point using bSSFP readout and allows for single-shot myocardial edema imaging. The sequence (T2STIR-bSSFP) was studied for its contrast behavior using simulation and phantoms. It was then evaluated on 7 healthy subjects and 7 AMI patients by comparing it to T2p-bSSFP and T2 mapping using the contrast-to-noise ratio (CNR) and the contrast ratio as performance indices. RESULTS In simulation and phantom studies, T2STIR-bSSFP had improved contrast between edema and normal myocardium compared with the other two edema imaging techniques. In patients, the CNR of T2STIR-bSSFP was higher than T2p-bSSFP (5.9 ± 2.6 vs. 2.8 ± 2.0, P < 0.05) but had no significant difference compared with that of the T2 map (T2 map: 6.6 ± 3.3 vs. 5.9 ± 2.6, P = 0.62). The contrast ratio of T2STIR-bSSFP (2.4 ± 0.8) was higher than that of the T2 map (1.3 ± 0.1, P < 0.01) and T2p-bSSFP (1.4 ± 0.5, P < 0.05). CONCLUSION T2STIR-bSSFP has improved contrast between edematous and normal myocardium compared with commonly used bSSFP-based edema imaging techniques. T2STIR-bSSFP also differentiates between fat that was robustly suppressed and fluids around the heart. The technique is useful for single-shot edema imaging in AMI patients.

中文翻译：

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用于单次心血管磁共振心肌水肿成像的 T2STIR 准备。


背景技术急性心肌梗死（AMI）中的心肌水肿通常使用暗血短tau反转恢复涡轮自旋回波（STIR-TSE）心血管磁共振（CMR）进行成像。该技术对心脏运动和线圈灵敏度变化敏感，导致心肌信号不均匀并妨碍可靠地描绘水肿组织。 T2准备的平衡稳态自由进动（T2p-bSSFP）成像已被提出，但其对比度较低，并且通常需要平均。 T2 映射很有用，但需要较长的扫描时间和屏气。我们在这里提出了一种单次磁化准备序列，可以增加水肿和正常心肌之间的对比度，并将其应用于心肌水肿成像。方法 磁化准备模块 (T2STIR) 旨在利用水肿中 T1 和 T2 的同时升高来改善对水肿心肌的描绘。 T2 准备后，模块将磁化强度向下倾斜至 -z 轴。使用 bSSFP 读数在脂肪零点对横向磁化进行采样，并允许单次心肌水肿成像。使用模拟和模型研究了序列 (T2STIR-bSSFP) 的对比行为。然后使用对比噪声比 (CNR) 和对比度作为性能指标，将其与 T2p-bSSFP 和 T2 映射进行比较，对 7 名健康受试者和 7 名 AMI 患者进行评估。结果在模拟和模型研究中，与其他两种水肿成像技术相比，T2STIR-bSSFP 改善了水肿和正常心肌之间的对比度。在患者中，T2STIR-bSSFP 的 CNR 高于 T2p-bSSFP（5.9 ± 2.6 vs. 2.8 ± 2.0，P < 0.05），但与 T2 图谱相比无显着性差异（T2 图谱：6.6 ± 3.3 vs. 2.8 ± 2.0）。 5.9±2.6，P=0。62）。 T2STIR-bSSFP的对比度（2.4±0.8）高于T2图（1.3±0.1，P<0.01）和T2p-bSSFP（1.4±0.5，P<0.05）。结论 与常用的基于 bSSFP 的水肿成像技术相比，T2STIR-bSSFP 改善了水肿心肌和正常心肌之间的对比度。 T2STIR-bSSFP 还可以区分被强力抑制的脂肪和心脏周围的液体。该技术对于 AMI 患者的单次水肿成像非常有用。