Fractal analysis of heart graft acute rejection microscopic images.

Abstract Background Endomyocardial biopsy to evaluate rejection in the transplanted heart is accepted at the “gold standard.” The complexity of microscopic images suggested using digital methods for precise evaluating of acute rejection episodes with numerical representation. The aim of the present was study to characterize digitally acute rejection of the transplanted heart using complexity/fractal image analysis. Material and Methods Biopsy samples harvested form 40 adult recipients after orthotropic heart transplantation were collected and rejection grade was evaluated according to the International Society for Heart and Lung Transplantation (0, 1a, 1b, or 3a) at transverse and longitudinal sections. Fifteen representative digital microscope images from each grade were collected and analyzed after Sobel edge detection and binarization. Results Only mean fractal dimension showed a progressive and significant increase and correlation based on rejection grade using longitudinal sections. Lacunarity and number of foreground pixels showed unequivocal results. Conclusion Mean fractal diameter could serve as auxiliary digital parameter for grading of acute rejection in the transplanted heart.