Zhu Jing, Chen Yushu, Xu Ziqian, Wang Shiyu, Wang Lei, Liu Xiaoxin, Gao Fabao
Department of Radiology, West China Hospital, Sichuan University, Chengdu, China.
Quant Imaging Med Surg. 2020 Nov;10(11):2157-2167. doi: 10.21037/qims-20-122.
Myocardial strain analysis can provide diagnostic and prognostic information for myocarditis. The aim of the present study was to assess early and acute myocarditis in a rat model using cardiac magnetic resonance tissue tracking (CMR-TT) for myocardial strain analysis. We compared the strain's findings with the histological and immunohistochemical results.
Experimental autoimmune myocarditis (EAM) was induced by footpad injections of porcine cardiac myosin. The rats were examined by 7.0T preclinical CMR at day 14 (n=15) and day 21 (n=16) after EAM induction and the two control groups (each n=15) were also examined at day 14 and day 21, respectively. Using CMR-TT, we found a global peak systolic radial strain (Err) and a circumferential strain (Ecc) from the short-axis cine views and a radial strain (Err) and a longitudinal strain (Ell) from the long-axis cine views, which were calculated by dedicated TT software. Subsequently, histological and immunohistochemical evaluations were performed.
Ell significantly decreased in early myocarditis compared with the control (-23.40%±1.48% . -22.02%±0.81%, P<0.05). Err, Ecc, Err, and Ell values significantly reduced in acute myocarditis compared with the controls (Err: 34.27%±9.80% . 49.76%±4.97%, Ecc: -18.98%±3.69% . -24.13±1.23, Err: 33.21%±10.24% . 49.59%±5.69%, and Ell: -17.75%±3.58% . -23.39%±1.48%; P<0.001, respectively). The receiver operating characteristic curve showed that myocardial strain analysis had a good diagnostic performance in early and acute myocarditis. The pathological evaluation revealed that inflammatory lesions began to appear in early myocarditis and peaked in acute myocarditis.
The CMR-TT strain analysis allowed accurate and reliable evaluation of early and acute myocarditis in a rat model, and has the potential to serve as a diagnostic indicator for the assessment of myocardial dysfunction in myocarditis.
心肌应变分析可为心肌炎提供诊断和预后信息。本研究的目的是使用心脏磁共振组织追踪（CMR-TT）进行心肌应变分析，以评估大鼠模型中的早期和急性心肌炎。我们将应变结果与组织学和免疫组化结果进行了比较。
通过足垫注射猪心肌肌凝蛋白诱导实验性自身免疫性心肌炎（EAM）。在EAM诱导后第14天（n = 15）和第21天（n = 16）对大鼠进行7.0T临床前CMR检查，两个对照组（每组n = 15）也分别在第14天和第21天进行检查。使用CMR-TT，我们从短轴电影视图中获得了整体峰值收缩期径向应变（Err）和圆周应变（Ecc），并从长轴电影视图中获得了径向应变（Err）和纵向应变（Ell），这些应变由专用的TT软件计算得出。随后进行了组织学和免疫组化评估。
与对照组相比，早期心肌炎时Ell显著降低（-23.40%±1.48% ，-22.02%±0.81%，P<0.05）。与对照组相比，急性心肌炎时Err、Ecc、Err和Ell值显著降低（Err：34.27%±9.80% ，49.76%±4.97%，Ecc：-18.98%±3.69% ，-24.13±1.23，Err：33.21%±10.24% ，49.59%±5.69%，Ell：-17.75%±3.58% ，-23.39%±1.48%；P均<0.001）。受试者工作特征曲线显示，心肌应变分析在早期和急性心肌炎中具有良好的诊断性能。病理评估显示，炎症病变在早期心肌炎时开始出现，并在急性心肌炎时达到高峰。
CMR-TT应变分析能够准确可靠地评估大鼠模型中的早期和急性心肌炎，并且有可能作为评估心肌炎心肌功能障碍的诊断指标。
