Figure 2.

Analysis of three example images using AutoTT. (A–C) The original (top), skeletalized (middle), and magnitude (bottom) images of three different cardiomyocytes are shown. Shown at the bottom is a table of output values corresponding to the three cells. Global T-tubule regularity is defined as the magnitude of the major frequency peak (red arrow) divided by the DC component (white arrow), which measures the overall regularity of the global T-tubule system. TE density is the total number of TE pixels divided by the area of the ROI as determined in the skeletalized image. LE density is the total number of LE pixels divided by the area of the ROI as determined in the skeletalized image. TE spacing is determined by converting the major spatial frequency into distance, or period. Index of T-tubule integrity (TT_int) takes into account the T-tubule regularity and density. To see this figure in color, go online.