Bruise chromophore concentrations over time

Abstract

During investigations of potential child and elder abuse, clinicians and forensic practitioners are often asked to offer opinions about the age of a bruise. A commonality between existing methods of bruise aging is analysis of bruise color or estimation of chromophore concentration. Relative chromophore concentration is an underlying factor that determines bruise color. We investigate a method of chromophore concentration estimation that can be employed in a handheld imaging spectrometer with a small number of wavelengths. The method, based on absorbance properties defined by Beer-Lambert's law, allows estimation of differential chromophore concentration between bruised and normal skin. Absorption coefficient data for each chromophore are required to make the estimation. Two different sources of this data are used in the analysis-generated using Independent Component Analysis and taken from published values. Differential concentration values over time, generated using both sources, show correlation to published models of bruise color change over time and total chromophore concentration over time.

Noninvasive Monitoring of Dynamical Processes in Bruised Human Skin Using Diffuse Reflectance Spectroscopy and Pulsed Photothermal Radiometry

“…Our results correspond very well to literature data, which stated that the bilirubin content (or ∆b* value in the case of colorimetric studies) typically peaks at 3-5 days [5,8,9,38,47]. However, longer times required to reach the bilirubin peak were also reported, i.e., 4-8 days [1] and up to 10 days [43], which supports the significantly slower dynamics seen in our subject b. Furthermore, all our examples demonstrate a subsequent gradual removal of the bilirubin.…”

“…These amount to 1–2 and 2–3 days in subjects a and c , respectively, but extend to 6–8 days in subject b . A similar variance of individual timelines, while universally showing a gradual decrease of the excess hemoglobin content as the bruise resolves, was reported by Duckworth et al [ 43 ] and Kim et al [ 8 ]. Such a variability could result from many uncontrolled factors, from the severity of the impact force, size, and structure of the injured blood vessel and the surrounding tissue, to the dynamics of RBC lysis, hemoglobin diffusion, and even dynamics of its decomposition and removal.…”

Systematic reviews of bruising in relation to child abuse—what have we learnt: an overview of review updates

“…Although promising, to date however, these techniques are not applicable in clinical practice for children. Other techniques explored have included an evaluation of chromophore concentrations to determine age, but this technique was found to be unreliable 22. The most recent work has investigated the use of ultrasound to aid the assessment of bruises in post‐mortem cases 23, as it was felt that a limiting feature in the potential application of spectrophotometry techniques may be the degree to which bruises vary depending on their depth and extent, which ultrasound may delineate 24.…”

Which injuries may indicate child abuse?

“…It is clear that not only do different colours appear in the same bruise at the same time, but each of us perceives colour differently, and we may not even agree with our own assessment of colour between the assessment of the live child and subsequent review of a photograph 27–29. New techniques are being explored which may offer a method of dating bruises, including reflectance spectroscopy, chromophore concentrations, etc, but these are not yet in clinical practice 30 31…”