Department of Radiology, The First Affiliated Hospital of Chongqing Medical University, Yuzhong District, Chongqing, 400016, China.
Department of Radiology, West China Hospital, Sichuan University, 37 Guo Xuexiang Road, Wuhou District, Chengdu, 610041, Sichuan, China.
BMC Med Imaging. 2021 Nov 20;21(1):173. doi: 10.1186/s12880-021-00709-x.
This study investigates the segmental myocardial strain of the early phase of intramyocardial hemorrhage (IMH) caused by reperfused myocardial infarction (MI) in rats by low-dose dobutamine (LDD) cardiovascular magnetic resonance (CMR) feature-tracking.
Nine sham rats and nine rats with 60-min myocardial ischemia followed by 48-h reperfusion were investigated using CMR, including T2*-mapping sequence and fast imaging with steady-state precession (FISP)-cine sequence. Another FISP-cine sequence was acquired after 2 min of dobutamine injection; the MI, IMH, and Non-MI (NMI) areas were identified. The values of peak radial strains (PRS) and peak circumferential strains (PCS) of the MI, IMH and NMI segments were acquired. The efficiency of PRS and PCS (EPRS and EPCS, respectively) were calculated on the basis of the time of every single heartbeat.
The PRS, PCS, EPRS, and EPCS of the sham group increased after LDD injection. However, the PRS, PCS, EPRS, and EPCS of the IMH segment did not increase. Moreover, the PRS and PCS of the MI and NMI segments did not increase, but the EPRS and EPCS of these segments increased. The PRS, PCS, EPRS, and EPCS of the IMH segment were lower than those of the MI and NMI segments before and after LDD injection, but without a significant difference between MI segment and NMI segment before and after LDD injection.
LDD could help assess dysfunctions in segments with IMH, especially using the efficiency of strain. IMH was a crucial factor that decreased segmental movement and reserved function.
本研究通过低剂量多巴酚丁胺（LDD）心血管磁共振（CMR）特征追踪技术，研究再灌注心肌梗死（MI）引起的早期心肌内出血（IMH）的节段心肌应变。
对 9 只假手术大鼠和 9 只 60 分钟心肌缺血后 48 小时再灌注大鼠进行 CMR 检查，包括 T2*-mapping 序列和快速稳态进动（FISP）电影序列。多巴酚丁胺注射 2 分钟后采集另一个 FISP 电影序列，识别 MI、IMH 和非 MI（NMI）区域。获取 MI、IMH 和 NMI 节段的峰值径向应变（PRS）和峰值周向应变（PCS）值。根据每个心动周期的时间计算 PRS 和 PCS 的效率（EPRS 和 EPCS）。
假手术组 LDD 注射后 PRS、PCS、EPRS 和 EPCS 增加。然而，IMH 节段的 PRS、PCS、EPRS 和 EPCS 没有增加。此外，MI 和 NMI 节段的 PRS 和 PCS 没有增加，但这些节段的 EPRS 和 EPCS 增加。LDD 注射前后 IMH 节段的 PRS、PCS、EPRS 和 EPCS 均低于 MI 和 NMI 节段，但 LDD 注射前后 MI 节段和 NMI 节段之间无显著差异。
LDD 可帮助评估 IMH 节段的功能障碍，尤其是使用应变效率。IMH 是降低节段运动和保留功能的关键因素。
