Cho Steven K S, Darby Jack R T, Williams Georgia K, Holman Stacey L, Rai Archana, Van Amerom Joshua F P, Fan Chun-Po, Macgowan Christopher K, Selvanayagam Joseph B, Morrison Janna L, Seed Mike
Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada.
Early Origins of Adult Health Research Group, Health and Biomedical Innovation, UniSA: Clinical and Health Sciences, University of South Australia, Adelaide, South Australia, Australia.
J Magn Reson Imaging. 2025 Mar;61(3):1323-1335. doi: 10.1002/jmri.29496. Epub 2024 Jun 28.
Cardiac MRI feature tracking (FT) allows objective assessment of segmental left ventricular (LV) function following a myocardial infarction (MI), but its utilization in sheep, where interventions can be tested, is lacking.
To apply and validate FT in a sheep model of MI and describe post-MI LV remodeling.
Animal model, longitudinal.
Eighteen lambs (6 months, male, n = 14; female, n = 4; 25.2 ± 4.5 kg).
FIELD STRENGTH/SEQUENCE: Two-dimensional balanced steady-state free precession (bSSFP) and 3D inversion recovery fast low angle shot (IR-FLASH) sequences at 3 T.
Seven lambs underwent test-retest imaging to assess FT interstudy reproducibility. MI was induced in the remaining 11 by coronary ligation with MRI being undertaken before and 15 days post-MI. Injury size was measured by late gadolinium enhancement (LGE) and LV volumes, LV mass, ejection fraction (LVEF), and wall thickness (LVWT) were measured, with FT measures of global and segmental radial, circumferential, and longitudinal strain.
Sampling variability, inter-study, intra and interobserver reproducibility were assessed using Pearson's correlation, Bland-Altman analyses, and intra-class correlation coefficients (ICC). Diagnostic performance of segmental strain to predict LGE was assessed using receiver operating characteristic curve analysis. Significant differences were considered P < 0.05.
Inter-study reproducibility of FT was overall good to excellent, with global strain being more reproducible than segmental strain (ICC = 0.89-0.98 vs. 0.77-0.96). MI (4.0 ± 3.7% LV mass) led to LV remodeling, as evident by significantly increased LV volumes and LV mass, and significantly decreased LVWT in injured regions, while LVEF was preserved (54.9 ± 6.9% vs. 55.6 ± 5.7%; P = 0.778). Segmental circumferential strain (CS) correlated most strongly with LGE. Basal and mid- CS increased significantly, while apical CS significantly decreased post-MI.
FT is reproducible and compensation by hyperkinetic remote myocardium may manifest as overall preserved global LV function.
N/A TECHNICAL EFFICACY: Stage 2.
心脏磁共振成像特征追踪（FT）能够客观评估心肌梗死（MI）后节段性左心室（LV）功能，但在可进行干预测试的绵羊模型中尚未得到应用。
在MI绵羊模型中应用并验证FT，并描述MI后LV重塑情况。
动物模型，纵向研究。
18只羔羊（6个月龄，雄性，n = 14；雌性，n = 4；体重25.2±4.5 kg）。
场强/序列：3T时的二维平衡稳态自由进动（bSSFP）序列和三维反转恢复快速低角度激发（IR-FLASH）序列。
7只羔羊接受重测成像以评估FT研究间的可重复性。其余11只通过冠状动脉结扎诱导MI，并在MI前和MI后15天进行MRI检查。通过延迟钆增强（LGE）测量梗死面积，测量LV容积、LV质量、射血分数（LVEF）和壁厚度（LVWT），并采用FT测量整体和节段性径向、圆周和纵向应变。
使用Pearson相关性、Bland-Altman分析和组内相关系数（ICC）评估抽样变异性、研究间、观察者内和观察者间的可重复性。使用受试者工作特征曲线分析评估节段应变预测LGE的诊断性能。差异有统计学意义定义为P < 0.05。
FT研究间的可重复性总体良好至优秀，整体应变比节段应变更具可重复性（ICC = 0.89 - 0.98 vs. 0.77 - 0.96）。MI（占LV质量的4.0±3.7%）导致LV重塑，表现为LV容积和LV质量显著增加，梗死区域LVWT显著降低，而LVEF得以保留（54.9±6.9% vs. 55.6±5.7%；P = 0.778）。节段圆周应变（CS）与LGE的相关性最强。MI后基底段和中段CS显著增加，而心尖段CS显著降低。
FT具有可重复性，高动力性远隔心肌的代偿可能表现为整体LV功能得以保留。
无 技术效能：2级
