Optical classification of bruises

Abstract

Determining the age of injuries is an important aspect of forensic medicine. Currently, visual inspection and colorimetric measurements are the most common techniques used to assess the age of bruises on a victim's body. Bruises are caused by trauma to the skin and vasculature, and the color will depend on the age, depth, and anatomic site of the hemorrhage. Breakdown products of hemoglobin e. g. biliverdin and bilirubin possess various colors, which can be determined spectrometrically. This study presents reflection spectra collected from bruises in otherwise healthy subjects. A total of 73 spectra of 25 bruises were measured on 13 individuals in the 400 -850 nm wavelength region. All injuries were caused by sports activities such as judo and soccer. The bruises were classified according to visual appearance, bilirubin content, oxygenation, and age of injury. Only bruises with known age and cause were included in the study. Spectral changes of each hematoma were recorded over several days. Preliminary results show large variation in the spectra, caused by differences in age and depth of the bruises. This data may provide a basis for developing an algorithm to determine the age of injuries in e. g. child abuse cases.

Skin changes following minor trauma

“…The visual appearance of a fresh bruise is mainly due to hemorrhage from ruptured vessels within the skin, and hemoglobin is therefore the predominant absorber. Bilirubin, methemoglobin, hemosiderin, and other hemoglobin breakdown products might be found in older bruises [1][2][3][4][13][14][15]. However, only fresh bruises were included in this study, and no traces of methemoglobin, hemosiderin or bilirubin could be identified in any of the spectra.…”

“…The visual appearance of a bruise will be dependent on the time after impact, and optical methods can be used to monitor and characterize the observed changes. Reflection spectroscopy has been applied to characterize bruises with good results [12][13][14][15]. Bohnert et al [12] published a relation between reflectance spectra, observed bruise color and depth of injury in post mortem cases.…”

“…They found that superficial hemorrhages cause bright red bruises, while deep subcutaneous bruises appear blue or purple. Hughes et al [13] used reflectance spectroscopy to quantify bilirubin in bruises of various age, and Randeberg et al [14] identified hemoglobin content in the skin, hemoglobin oxygenation, and bilirubin content as potential indicators of bruise age. Randeberg et al [15] later published a mathematical model to predict the age of a bruise from a reflectance measurement.…”

A novel approach to age determination of traumatic injuries by reflectance spectroscopy

“…Bohnert et al [15] used reflectance spectroscopy to study the depth and color of contusions post mortem, and found that shallow fresh bruises appear bright red, and deeper injuries show a more bluish color. Reflectance spectroscopy of bruises in vivo has also been carried out with promising results [16,17]. To further enhance the value of reflectance spectroscopy, the physics behind the changing skin appearance must be considered.…”

Use of reflectance spectrophotometry and colorimetry in a general linear model for the determination of the age of bruises

“…Forensic investigators would benefit from a noninvasive, objective, scientifically validated method for determining the age of bruises. Previous authors have suggested that either colorimetry or reflectance spectrophotometry might provide a solution [13][14][15].…”