Rajakulasingam Ramyah, Ferreira Pedro F, Scott Andrew D, Khalique Zohya, Azzu Alessia, Molto Maria, Conway Miriam, Falaschetti Emanuela, Cheng Kevin, Hammersley Daniel J, Cantor Emily-Jane, Tindale Alexander, Beattie Catherine J, Banerjee Arjun, Wage Ricardo, Soundarajan Raj K, Dalby Miles, Nielles-Vallespin Sonia, Pennell Dudley J, de Silva Ranil
National Heart and Lung Institute, Imperial College London, London SW3 6LY, UK.
Royal Brompton and Harefield Hospitals, Guy's and St Thomas' NHS Foundation Trust, London SW3 6NP, UK.
Eur Heart J. 2025 Feb 3;46(5):454-469. doi: 10.1093/eurheartj/ehae667.
Microstructural disturbances underlie dysfunctional contraction and adverse left ventricular (LV) remodelling after ST-elevation myocardial infarction (STEMI). Biphasic diffusion tensor cardiovascular magnetic resonance (DT-CMR) quantifies dynamic reorientation of sheetlets (E2A) from diastole to systole during myocardial thickening, and markers of tissue integrity [mean diffusivity (MD) and fractional anisotropy (FA)]. This study investigated whether microstructural alterations identified by biphasic DT-CMR: (i) enable contrast-free detection of acute myocardial infarction (MI); (ii) associate with severity of myocardial injury and contractile dysfunction; and (iii) predict adverse LV remodelling.
Biphasic DT-CMR was acquired 4 days (n = 70) and 4 months (n = 66) after reperfused STEMI and in healthy volunteers (HVOLs) (n = 22). Adverse LV remodelling was defined as an increase in LV end-diastolic volume ≥ 20% at 4 months. MD and FA maps were compared with late gadolinium enhancement images.
Widespread microstructural disturbances were detected post-STEMI. In the acute MI zone, diastolic E2A was raised and systolic E2A reduced, resulting in reduced E2A mobility (all P < .001 vs. adjacent and remote zones and HVOLs). Acute global E2A mobility was the only independent predictor of adverse LV remodelling (odds ratio .77; 95% confidence interval .63-.94; P = .010). MD and FA maps had excellent sensitivity and specificity (all > 90%) and interobserver agreement for detecting MI presence and location.
Biphasic DT-CMR identifies microstructural alterations in both diastole and systole after STEMI, enabling detection of MI presence and location as well as predicting adverse LV remodelling. DT-CMR has potential to provide a single contrast-free modality for MI detection and prognostication of patients after acute STEMI.
微观结构紊乱是ST段抬高型心肌梗死（STEMI）后功能失调性收缩和不良左心室（LV）重构的基础。双相扩散张量心血管磁共振成像（DT-CMR）可量化心肌增厚过程中舒张期至收缩期心肌薄片（E2A）的动态重新定向，以及组织完整性标志物[平均扩散率（MD）和分数各向异性（FA）]。本研究调查了双相DT-CMR识别的微观结构改变是否：（i）能够在无对比剂的情况下检测急性心肌梗死（MI）；（ii）与心肌损伤严重程度和收缩功能障碍相关；（iii）预测不良LV重构。
在再灌注STEMI后4天（n = 70）和4个月（n = 66）以及健康志愿者（HVOLs）（n = 22）中采集双相DT-CMR。不良LV重构定义为4个月时LV舒张末期容积增加≥20%。将MD和FA图与延迟钆增强图像进行比较。
STEMI后检测到广泛的微观结构紊乱。在急性MI区域，舒张期E2A升高而收缩期E2A降低，导致E2A移动性降低（与相邻和远处区域及HVOLs相比，所有P <.001）。急性整体E2A移动性是不良LV重构的唯一独立预测因子（优势比.77；95%置信区间.63-.94；P =.010）。MD和FA图在检测MI的存在和位置方面具有出色的敏感性和特异性（均> 90%）以及观察者间一致性。
双相DT-CMR可识别STEMI后舒张期和收缩期的微观结构改变，能够检测MI的存在和位置以及预测不良LV重构。DT-CMR有可能为急性STEMI后患者的MI检测和预后提供一种单一的无对比剂检查方法。
