Colorimetry for wall appearance study of cerebral aneurysms

Abstract

Background: Neurosurgeons 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. Methods: In 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”. Results: Significantly 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). Conclusions: ARI 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.

Keywords

• Cerebral aneurysm
• Aneurysm wall characteristics
• Colorimetry
• CIE L*a*b*
• Digital Color Meter
• Aneurysm Red Indicator