Department of Information and Communication Technologies, Universitat Pompeu Fabra, c. Roc Boronat 138, Barcelona 08018, Spain.
Department of Information and Communication Technologies, Universitat Pompeu Fabra, c. Roc Boronat 138, Barcelona 08018, Spain; ICREA, Passeig Lluís Companys, 23, Barcelona 08018, Spain; KU Leuven, Oude Markt 13, Leuven 3000, Belgium.
Med Image Anal. 2018 Oct;49:89-104. doi: 10.1016/j.media.2018.08.001. Epub 2018 Aug 2.
During embryogenesis, a mammalian heart develops from a simple tubular shape into a complex 4-chamber organ, going through four distinct phases: early primitive tubular heart, emergence of trabeculations, trabecular remodeling and development of the compact myocardium. In this paper we propose a framework for standardized and subject-independent 3D regional myocardial complexity analysis, applied to analysis of the development of the mouse left ventricle. We propose a standardized subdivision of the myocardium into 3D overlapping regions (in our case 361) and a novel visualization of myocardial complexity, whereupon we: 1) extend the fractal dimension, commonly applied to image slices, to 3D and 2) use volume occupied by the trabeculations in each region together with their surface area, in order to quantify myocardial complexity. The latter provides an intuitive characterization of the complexity, given that compact myocardium will tend to occupy a larger volume with little surface area while high surface area with low volume will correspond to highly trabeculated areas. Using 50 mouse embryo images at 5 different gestational ages (10 subjects per gestational age), we demonstrate how the proposed representation and complexity measures describe the development of LV myocardial complexity. The mouse embryo data was acquired using high resolution episcopic microscopy. The complexity analysis per region was carried out using: 3D fractal dimension, myocardial volume, myocardial surface area and ratio between the two. The analysis of gestational ages was performed on embryos of 14.5, 15.5, 16.5, 17.5 and 18.5 embryonic days, and demonstrated that the regional complexity of the trabeculations increases longitudinally from the base to the apex, with a maximum around the middle. The overall complexity decreases with gestational age, being most complex at 14.5. Circumferentially, at ages 14.5, 15.5 and 16.5, the trabeculations show similar complexity everywhere except for the anteroseptal and inferolateral area of the wall, where it is smaller. At 17.5 days, the regions of high complexity become more localized towards the inferoseptal and anterolateral parts of the wall. At 18.5 days, the high complexity area exhibits further localization at the inferoseptal and anterior part of the wall.
在胚胎发生过程中，哺乳动物心脏从简单的管状形状发育成复杂的 4 腔器官，经历了四个不同的阶段：早期原始管状心脏、小梁的出现、小梁重塑和致密心肌的发育。在本文中，我们提出了一个标准化和与主体无关的 3D 区域性心肌复杂性分析框架，应用于分析小鼠左心室的发育。我们将心肌标准化地划分为 3D 重叠区域（在我们的情况下为 361 个），并提出了一种新的心肌复杂性可视化方法，在此基础上：1）将分形维数（通常应用于图像切片）扩展到 3D 2）使用每个区域中小梁占据的体积及其表面积，以量化心肌复杂性。后者直观地描述了复杂性，因为致密心肌将倾向于占据较小表面积的较大体积，而具有高表面积的小体积则对应于高度小梁化的区域。使用 50 个不同妊娠龄（每个妊娠龄 10 个）的小鼠胚胎图像，我们展示了所提出的表示和复杂性度量如何描述 LV 心肌复杂性的发育。小鼠胚胎数据是使用高分辨率外显显微镜采集的。对每个区域的复杂性分析使用：3D 分形维数、心肌体积、心肌表面积和两者之比。对妊娠龄的分析是在 14.5、15.5、16.5、17.5 和 18.5 天的胚胎上进行的，结果表明，小梁的区域性复杂性从基底到心尖纵向增加，在中部达到最大值。随着妊娠龄的增加，整体复杂性逐渐降低，在 14.5 天时最为复杂。在 14.5、15.5 和 16.5 岁时，圆周上的小梁在除了壁的前间隔和下外侧区域之外的所有地方都显示出相似的复杂性，而在这些区域，复杂性较小。在 17.5 天时，高复杂性区域变得更加局限于壁的下间隔和前外侧部分。在 18.5 天，高复杂性区域在前间隔和前壁部分进一步局限。
