Fig. 2

Quantification of non-contractile tissue was performed by analyzing grayscale values of pixels within the region of interest (ROI). The graphs represent examples of the distribution of pixels based on grayscale values in the ROI from the corresponding MRI’s (low and high non-contractile tissue content). A threshold was set at a grayscale value of 60. Grayscale values ≤ 60 were considered to present contractile tissue and grayscale values > 60 were considered to present non-contractile tissue. The percentage of non-contractile tissue was calculated as the number of non-contractile pixels (grayscale value > 60) divided by the total number of pixels