title: Concurrent validation and reliability of digital image analysis of granulation tissue color for clinical pressure ulcers.
abstract: Granulation tissue color is one indicator for pressure ulcer (PU) assessment. However, it entails a subjective evaluation only, and quantitative methods have not been established. We developed color indicators from digital image analysis and investigated their concurrent validity and reliability for clinical PUs. A cross-sectional study was conducted on 47 patients with 55 full-thickness PUs. After color calibration, a wound photograph was converted into three images representing red color: erythema index (EI), modified erythema index with additional color calibration (granulation red index [GRI]), and , which represents the artificially created red-green axis of L(*) a(*) b(*) color space. The mean intensity of the granulation tissue region and the percentage of pixels exceeding the optimal cutoff intensity (% intensity) were calculated. Mean GRI (ρ=0.39, p=0.007) and (ρ=0.55, p<0.001), as well as their % intensity indicators, showed positive correlations with a(*) measured by tristimulus colorimeter, but erythema index did not. They were correlated with hydroxyproline concentration in wound fluid, healthy granulation tissue area, and blood hemoglobin level. Intra- and interrater reliability of the indicator calculation using both GRI and had an intraclass correlation coefficient >0.9. GRI and from digital image analysis can quantitatively evaluate granulation tissue color of clinical PUs.
authors.affiliation: Department of Gerontological Nursing/Wound Care Management, Division of Health Sciences and Nursing, Graduate School of Medicine, The University of Tokyo, Japan.
authors.forename: Shinji
authors.initials: S
authors.lastname: Iizaka
authors.forename: Junko
authors.initials: J
authors.lastname: Sugama
authors.forename: Gojiro
authors.initials: G
authors.lastname: Nakagami
authors.forename: Toshiko
authors.initials: T
authors.lastname: Kaitani
authors.forename: Ayumi
authors.initials: A
authors.lastname: Naito
authors.forename: Hiroe
authors.initials: H
authors.lastname: Koyanagi
authors.forename: Junko
authors.initials: J
authors.lastname: Matsuo
authors.forename: Takafumi
authors.initials: T
authors.lastname: Kadono
authors.forename: Chizuko
authors.initials: C
authors.lastname: Konya
authors.forename: Hiromi
authors.initials: H
authors.lastname: Sanada
mesh_terms: D000369:Aged, 80 and over; D003430:Cross-Sectional Studies; D004890:Erythema / Q000473:pathology; D005122:Exudates and Transudates / Q000378:metabolism; D005260:Female; D006097:Granulation Tissue / Q000473:pathology*; D006454:Hemoglobins / Q000032:analysis; D006801:Humans; D006909:Hydroxyproline / Q000378:metabolism; D007089:Image Enhancement / Q000379:methods; D007091:Image Processing, Computer-Assisted; D008297:Male; D010781:Photography; D003668:Pressure Ulcer / Q000473:pathology*; D015203:Reproducibility of Results; D012880:Skin Pigmentation; D012984:Software
chemical_list: D006454:Hemoglobins; D006909:Hydroxyproline