Quantitative Performance Evaluation of Commonly Used Colormaps for Image Display in Myocardial Perfusion Imaging: Analysis based on Perceptual Metrics.

Objectives: To quantitatively evaluate the performance of the most used colormaps in image display using perceptual metrics and to what extent these measures are congruent with the true intensity or uptake of pixels at different levels of defect severity in simulated cardiac images. Methods: Six colormaps, labeled "Gray", "Thermal", "Cool", "CEqual", "Siemens" and "S Pet" extracted from FIJI ImageJ software are included. Colormap data are converted from the red, green, blue color space to CIELAB. Perceptual metrics for measuring "color difference" were calculated, including difference (ΔE Results: In 0% defect, all the curves are at the highest level, except for "s pet", in that the lightness is not at its maximum value. In the phantom with 10% defect (or 90% of maximum value), discrepancies among curves appear. In "Siemens", the ΔE Conclusion: Of 6 colormaps investigated for estimating defect severity, "grayscale" is less favorable than others and "thermal" performs slightly better. "S pet" or rainbow, which is used traditionally by many practitioners, is strongly discouraged. The "Siemens" colormap suffers from decreased discriminating power in the range of mild to moderate/severe. In contrast, the "cool" and "cequal" colormaps outperform the other colormaps employed in this study to some extent, although they have some shortcomings.