Description of the Intrusion Angle of Local Cardiomyocyte Aggregates in Human Left Ventricular Free Wall Using X-ray Phase-Contrast Tomography

Abstract

A better knowledge of the radial orientation of myocytes from the left ventricular wall’s endo- to epi-side may promote our understanding of the cardiac work mechanisms and diseases. The transverse angle is the most used angle, which depicts the myocyte aggregates’ angles on the horizontal plane. Compared with the transverse angle, the intrusion angle (IA) can avoid the influence of projection and better describe the radial orientation of local myocyte aggregates. In this preliminary study, we used a simple empirical formula to fit the distribution of IA in three human left ventricular transparietal tissue samples. The samples were imaged using X-ray phase-contrast tomography, and reconstructed with an isotropic 3.5 μm3 voxel size. We calculated the mean myocyte aggregates IA in each window (112 × 112 × 112 μm3), which is regularly spaced in three-dimension and the adjacent ones have a half overlap. The results present that, in small-sized transparietal samples, the IA experiences a quadratic function along the local radial direction and linear functions along longitudinal and circumferential directions. The distribution of IA in the left ventricle is regional.