Forensic age estimation based on the pigmentation in the costal cartilage from human mortal remains

• Published in: Legal medicine (Tokyo, Japan) Japan), 2019-09, Vol.40, p.32-36
• Main Authors: Meng, Hang, Zhang, Mingchang, Xiao, Bi, Chen, Xin, Yan, Jianjun, Zhao, Ziqin, Ma, Kaijun, Shen, Yiwen, Xie, Jianhui
• Format: Article
• Language: English
• Subjects: Adolescent; Adult; Age estimation; Age Factors; Aged; Aged, 80 and over; Autopsy; Child; Costal cartilage; Costal Cartilage - anatomy & histology; Female; Forensic anthropology; Forensic Anthropology - methods; Humans; Image Processing, Computer-Assisted; Male; Mean grey value; Middle Aged; Pigmentation
• ISSN: 1344-6223; 1873-4162
• DOI: 10.1016/j.legalmed.2019.07.004

•A correlative color alteration with advancing age was observed in costal cartilage.•Mean gray value (MGV) was introduced to quantify the pigmentation of costal cartilage.•Age, but not gender, shows a significant relationship with MGV.•A linear regression model based on MGV was constructed for age estimation. Age estimation is considered a crucial and challenging issue in forensic casework. Costal cartilage appears a potential mortal remain in age-at-death estimation attributable to its correlative alteration in color based on pigment accumulation with the advancing age. In this study, samples from the second costal cartilage were collected in a Chinese Han population, and the cross sections were subsequently scanned and digitalized in a standard way. Color change was quantified using mean gray value (MGV), which was measured by Photoshop CS5. After the exclusion of samples with factors which could impair the quality of images and the accuracy of values, a high correlation was demonstrated between age and MGV in samples. A linear regression model (AGE = 173.425–0.755*aveMGV) was established for age prediction, with its performance evaluated using both samples from the training set and the blind test set, in which a mean absolute deviation of 4.42 years and 3.57 years was obtained, respectively. Altogether, MGV could be reckoned as a precise quantification of pigmentation in costal cartilage and an excellent indicator of age prediction in the age interval from 20 to 60 years. Moreover, our strategy appears more user-friendly and accurate, thus exceedingly practical for age estimation in forensic anthropology.