BACKGROUND Although cardiac magnetic resonance (CMR) can accurately quantify global left ventricular strain using feature tracking (FT), it has been suggested that FT cannot reliably quantify regional strain. We aimed to determine whether abnormalities in regional strain measured using FT can be detected within areas of myocardial scar and to determine the extent to which the regional strain measurement is impacted by LV ejection fraction (EF). METHODS We retrospectively studies 96 patients (46 with LVEF ≤ 40%, 50 with LVEF > 40%) with coronary artery disease and a late gadolinium enhancement (LGE) pattern consistent with myocardial infarction, who underwent CMR imaging (1.5T). Regional peak systolic longitudinal and circumferential strains (RLS, RCS) were measured within LGE and non-LGE areas. Linear regression analysis was performed for strain in both areas against LVEF to determine whether the relationship between strain and LGE holds across the LV function spectrum. Receiver-operating curve (ROC) analysis was performed in 33 patients (derivation cohort) to optimize strain cutoff, which was tested in the remaining 63 patients (validation cohort) for its ability to differentiate LGE from non-LGE areas. RESULTS Both RLS and RCS magnitudes were reduced in LGE areas: RLS = -10.4 ± 6.2% versus -21.0 ± 8.5% (p < 0.001); RCS = -10.4 ± 6.0% versus -18.9 ± 8.6%, respectively (p < 0.001), but there was considerable overlap between LGE and non-LGE areas. Linear regression revealed that it was partially driven by the natural dependence between strain and EF, suggesting that EF-corrected strain cutoff is needed to detect LGE. ROC analysis showed the ability of both RLS and RCS to differentiate LGE from non-LGE areas: area under curve 0.95 and 0.89, respectively. In the validation cohort, optimal cutoffs of RLS/EF = 0.36 and RCS/EF = 0.37 yielded sensitivity, specificity and accuracy 0.74-0.78. CONCLUSION Abnormalities in RLS and RCS within areas of myocardial scar can be detected using CMR-FT; however, LVEF must be accounted for.

中文翻译：

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通过心脏磁共振特征跟踪来检测局部心肌应变，以检测缺血性心脏病中的疤痕。

背景技术尽管心脏磁共振（CMR）可以使用特征跟踪（FT）准确地量化整体左心室应变，但已提出FT无法可靠地量化局部应变。我们旨在确定是否可以在心肌疤痕区域内检测到使用FT测量的局部应变异常，并确定该区域应变测量受LV射血分数（EF）影响的程度。方法我们回顾性研究了96例行CMR成像（1.5T）的冠心病和晚期a增强（LGE）模式（与心肌梗死相符）的患者（LVEF≤40％的46例，LVEF> 40％的50例）。在LGE和非LGE区域内测量了区域峰值收缩期纵向和周向应变（RLS，RCS）。在两个区域对LVEF进行应变线性回归分析，以确定应变和LGE之间的关系在整个LV功能谱中是否成立。在33例患者（派生队列）中进行了接收者操作曲线（ROC）分析，以优化菌株截止值，在其余63例患者（验证队列）中测试了其区分LGE与非LGE区域的能力。结果LGE区域的RLS和RCS幅度均降低：RLS = -10.4±6.2％对-21.0±8.5％（p <0.001）；RCS分别为-10.4±6.0％和-18.9±8.6％（p <0.001），但LGE和非LGE区域之间存在相当大的重叠。线性回归表明，它部分是由菌株和EF之间的自然依赖性驱动的，这表明需要用EF校正的菌株截止值来检测LGE。ROC分析显示RLS和RCS都有能力区分LGE和非LGE区域：曲线下面积分别为0.95和0.89。在验证队列中，RLS / EF = 0.36和RCS / EF = 0.37的最佳临界值产生的敏感性，特异性和准确性为0.74-0.78。结论可以使用CMR-FT检测心肌瘢痕区域内RLS和RCS的异常。但是，必须考虑LVEF。