背景:心脏MRI特征跟踪(FT)可以客观评估心肌梗死(MI)后的节段性左心室(LV)功能,但是它在绵羊身上的利用,可以测试干预措施的地方,缺乏。
目的:在绵羊MI模型中应用和验证FT并描述MI后LV重塑。
方法:动物模型,纵向。
■18只羔羊(6个月,男性,n=14;女性,n=4;25.2±4.5kg)。
■3T时的二维平衡稳态自由进动(bSSFP)和3D反演恢复快速低角度拍摄(IR-FLASH)序列
结果:七只羔羊进行了测试-测试成像,以评估FT研究间的可重复性。在其余11例中,通过冠状动脉结扎诱发MI,在MI之前和之后15天进行MRI。损伤大小通过晚期钆增强(LGE)和LV体积来测量,低压质量,射血分数(LVEF),测量壁厚(LVWT),采用整体和分段径向的FT度量,圆周,和纵向应变。
方法:采样变异性,研究间,观察者内和观察者间的可重复性使用皮尔逊相关性进行评估,Bland-Altman分析,和类内相关系数(ICC)。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。显著差异被认为P<0.05。
结果:FT的研究间再现性总体良好至优异,全局应变比节段应变更具可重复性(ICC=0.89-0.98与0.77-0.96)。MI(4.0±3.7%左心室质量)导致左心室重塑,左心室容量和左心室质量显著增加,损伤区域的LVWT显着降低,而LVEF得到保留(54.9±6.9%vs.55.6±5.7%;P=0.778)。节段周向应变(CS)与LGE的相关性最强。基础和中期CS显著增加,心尖CS显著降低。
结论:FT是可重复的,远隔心肌运动过度补偿可能表现为整体保留的左心室功能。
方法:不适用技术效率:第二阶段。
BACKGROUND: 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.
OBJECTIVE: To apply and validate FT in a sheep model of MI and describe post-MI LV remodeling.
METHODS: Animal model, longitudinal.
UNASSIGNED: Eighteen lambs (6 months, male, n = 14; female, n = 4; 25.2 ± 4.5 kg).
UNASSIGNED: Two-dimensional balanced steady-state free precession (bSSFP) and 3D inversion recovery fast low angle shot (IR-FLASH) sequences at 3 T.
RESULTS: 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.
METHODS: 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.
RESULTS: 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.
CONCLUSIONS: FT is reproducible and compensation by hyperkinetic remote myocardium may manifest as overall preserved global LV function.
METHODS: N/A TECHNICAL EFFICACY: Stage 2.