Department of Mechanical Engineering, University of Kentucky, Lexington, KY, United States.
Department of Mechanical Engineering, University of Kentucky, Lexington, KY, United States; Department of Bioengineering, University of California, San Diego, CA, United States.
J Biomech. 2019 Sep 20;94:219-223. doi: 10.1016/j.jbiomech.2019.07.026. Epub 2019 Jul 31.
Statistical data from clinical studies suggests that right ventricular (RV) circumferential strain (E) and longitudinal strain (E) are significant biomarkers for many cardiovascular diseases. However, a detailed and regional characterization of these strains in the RV is very limited. In the current study, RV images were obtained with 3D spiral cine DENSE MRI in healthy rats. An algorithm for surface growing was proposed in order to fit irregular topology. Specifically, a new custom plugin for the DENSEanalysis program, called 3D DENSE Plugin for Crescent Organ, was developed for surface reconstruction and precise segmentation of organs with sharp curvature, such as the murine RV. The RV free wall (RVFW) was divided into three longitudinal thirds (i.e., basal, middle, and apical) with each one partitioned into circumferential fourths (i.e., anterior, anteriorlateral, inferiorlateral and inferior). Peak systolic strains were quantified for each segment and comparisons were performed statistically. The inclusion of a new plugin was able to generate global values for E and E that are in good agreement with previous findings using MRI. Despite no regional variation found in the peak E, the peak E exhibited regional variation at the anterior side of the RV, which is potentially due to differences in biventricular torsion at the RV insertion point and fiber architecture. These results provide fundamental insights into the regional contractile function of the RV in healthy rat and could act as a normative baseline for future studies on regional changes induced by disease or treatment.
临床研究的统计数据表明，右心室（RV）环向应变（E）和纵向应变（E）是许多心血管疾病的重要生物标志物。然而，对 RV 中这些应变的详细和区域性特征描述非常有限。在本研究中，使用 3D 螺旋 cine DENSE MRI 在健康大鼠中获得 RV 图像。提出了一种用于表面生长的算法，以适应不规则的拓扑结构。具体来说，为了进行表面重建和对曲率较锐的器官（如鼠 RV）进行精确分割，开发了一个名为“3D DENSE 插件 Crescent Organ”的新的定制插件，用于 DENSEanalysis 程序。将 RV 游离壁（RVFW）分为三个纵向三分之一（即基底、中间和心尖），每个三分之一又分为四个环向四分之一（即前、前外侧、下外侧和下侧）。对每个节段的收缩期峰值应变进行量化，并进行统计学比较。新插件的包含能够生成与以前使用 MRI 获得的 E 和 E 的全局值非常吻合。尽管在峰值 E 中没有发现区域性变化，但在 RV 的前侧发现了峰值 E 的区域性变化，这可能是由于 RV 插入点和纤维结构的双心室扭转的差异所致。这些结果为健康大鼠 RV 的区域性收缩功能提供了基本的见解，并可为未来研究疾病或治疗引起的区域性变化提供参考。
