BACKGROUND It has recently been suggested that myocardial oedema follows a bimodal pattern early post ST-segment elevation myocardial infarction (STEMI). Yet, water content, quantified using tissue desiccation, did not return to normal values unlike oedema quantified by cardiovascular magnetic resonance (CMR) imaging. We studied the temporal changes in the extent and intensity of injured myocardium using T1-mapping technique within the first week after STEMI. METHODS A first group (n = 31) underwent 3 acute 3 T CMR scans (time-point (TP) < 3 h, 24 h and 6 days), including cine, native shortened modified look-locker inversion recovery T1 mapping, T2* mapping and late gadolinium enhancement (LGE). A second group (n = 17) had a single scan at 24 h with an additional T2-weighted sequence to assess the difference in the extent of area-at-risk (AAR) compared to T1-mapping. RESULTS The mean T1 relaxation time value within the AAR of the first group was reduced after 24 h (P < 0.001 for TP1 vs.TP2) and subsequently increased at 6 days (P = 0.041 for TP2 vs.TP3). However, the extent of AAR quantified using T1-mapping did not follow the same course, and no change was detected between TP1&TP2 (P = 1.0) but was between TP2 &TP3 (P = 0.019). In the second group, the extent of AAR was significantly larger on T1-mapping compared to T2-weighted (42 ± 15% vs. 39 ± 15%, P = 0.025). No change in LGE was detected while microvascular obstruction and intra-myocardial haemorrhage peaked at different time points within the first week of reperfusion. CONCLUSION The intensity of oedema post-STEMI followed a bimodal pattern; while the extent of AAR did not track the same course. This discrepancy has implications for use of CMR in this context and may explain the previously reported disagreement between oedema quantified by imaging and tissue desiccation.

中文翻译：

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使用 T1 映射心血管磁共振对急性心肌梗死后早期受损心肌的动态变化进行量化。


背景最近有人提出，心肌水肿在ST段抬高型心肌梗死(STEMI)后早期遵循双峰模式。然而，与心血管磁共振（CMR）成像量化的水肿不同，使用组织干燥量化的水含量并没有恢复到正常值。我们使用 T1 映射技术研究了 STEMI 后第一周内心肌损伤范围和强度的时间变化。方法 第一组 (n = 31) 接受 3 次急性 3 T CMR 扫描（时间点 (TP) < 3 小时、24 小时和 6 天），包括电影、本地缩短修改的 Look-Locker 反转恢复 T1 映射、T2*测绘和后期钆增强（LGE）。第二组 (n = 17) 在 24 小时进行一次扫描，并附加 T2 加权序列，以评估与 T1 映射相比风险区域 (AAR) 范围的差异。结果 第一组 AAR 内的平均 T1 弛豫时间值在 24 小时后减少（TP1 与 TP2 的 P < 0.001），随后在 6 天时增加（TP2 与 TP3 的 P = 0.041）。然而，使用 T1 映射量化的 AAR 程度并不遵循相同的过程，并且在 TP1 和 TP2 之间（P = 1.0）没有检测到变化，但在 TP2 和 TP3 之间检测到变化（P = 0.019）。在第二组中，与 T2 加权相比，T1 映射的 AAR 程度显着更大（42 ± 15% 与 39 ± 15%，P = 0.025）。 LGE 未检测到变化，而微血管阻塞和心肌内出血在再灌注第一周内的不同时间点达到峰值。结论 STEMI 后水肿强度呈双峰模式；而 AAR 的范围并没有遵循同样的路线。 这种差异对于 CMR 在这种情况下的使用具有影响，并且可以解释之前报道的通过成像量化的水肿与组织干燥之间的分歧。