Figure 2

Comparison of structural parameters in region 1 (near the base of the heart) and region 2 (near to the apex of the heart) of a sham heart. (A) In region 1, the filament spacing is homogeneous, with the sole exception of a small layer in the outer myocardium where the filament spacing is increased, indicated by red arrows. (B) The filament spacing in region 2 resembles the distribution in region 1. In contrast to (A), the thin epicardial layer, indicated by a red arrow in a zoom inset, is now clearly visible. Note that in this layer the filament spacing is reduced. Sections from both regions appear very similar in shape and size. Total scattered intensity and peak intensity is increased around the left ventricle and filaments circulate smoothly around the left ventricle. (C) K-means clustering based on the five-dimensional dataset of fit parameters was used to identify three distinct clusters which are color-coded in (C). (D) Histograms of lattice spacings corresponding to the three clusters identified in (C). (E) Logical maps of the three clusters demonstrate more clearly, that cluster 1 with lattice spacings below 38.9 nm accounts well for the thin epicardial layer while cluster 2 represents the myocardium, with the exception of cluster 3 that highlights the outer myocardial layer with lattice spacings above 40.4 nm. Scale bar: 1 mm. RV right ventricle; LV left ventricle.