Colorimetry for wall appearance study of cerebral aneurysms

Abstract

BackgroundNeurosurgeons can assess thin red walls in a cerebral aneurysm during a microsurgical procedure, but the judgment of the color is subjective and could have a bias. This study aimed to quantitatively evaluate the aneurysm wall characteristics. MethodsIn 15 unruptured cerebral aneurysms, the surface color of cerebral aneurysms, parent arteries and branches were measured using Commission International del’Eclairage L*a*b*. The values of L* (perceptual lightness), a* (red-green color characteristics) and b* (blue-yellow color characteristics) were compared with color discrimination by two independent neurosurgeons, which was classified into “red”, “yellow”, “white” and “unjudged”. ResultsSignificantly lower L* and higher a* values were shown in red wall points consistently judged by both neurosurgeons compared with yellow or white wall points, while b* values had no significant differences. Based on these results, a novel index, aneurysm red indicator (ARI) was developed as a ratio of a* to L* values. The ARI had a high sensitivity and specificity to discriminate red walls (0.984 and 0.986, respectively). ConclusionsARI could be useful for evaluating thin red walls of cerebral aneurysms. The novel approach using colorimetry may contribute to future hemodynamics analyses related to the aneurysm wall characteristics.