Magnetic resonance imaging (MRI) of bruises: a pilot study

Pulsed Photothermal Radiometric Depth Profiling of Bruises by 532 nm and 1064 nm Lasers

Optical techniques are often inadequate in estimating bruise age since they are not sensitive to the depth of chromophores at the location of the bruise. To address this shortcoming, we used pulsed photothermal radiometry (PPTR) for depth profiling of bruises with two wavelengths, 532 nm (KTP laser) and 1064 nm (Nd:YAG laser). Six volunteers with eight bruises of exactly known and documented times of injury were enrolled in the study. A homogeneous part of the bruise was irradiated first with a 5 ms pulse at 532 nm and then with a 5 ms pulse at 1064 nm. The resulting transient surface temperature change was collected with a fast IR camera. The initial temperature-depth profiles were reconstructed by solving the ill-posed inverse problem using a custom reconstruction algorithm. The PPTR signals and reconstructed initial temperature profiles showed that the 532 nm wavelength probed the shallow skin layers revealing moderate changes during bruise development, while the 1064 nm wavelength provided additional information for severe bruises, in which swelling was present. Our two-wavelength approach has the potential for an improved estimation of the bruise age, especially if combined with modeling of bruise dynamics.

Determination of the age of bruises using a bilirubinometer

The dating of bruises can be of crucial interest in clinical forensic medicine, but the macroscopic or photographic evaluation of a bruise has not been regarded as reliable. Several methods have thus been regularly evaluated for this purpose, with reflectance spectrometry yielding promising results. The objective of this study is to evaluate the value of a bilirubinometer as a tool for dating bruises on living victims. A clinical follow-up was carried out on patients presenting a bruise with a known onset. Using a bilirubinometer, we obtained daily measurements of the bruise (bili-bruise) and of healthy skin (bili-skin). Potential confounding factors were collected: age, sex, body mass index, trauma mechanism and Fitzpatrick skin phototype. We followed 20 patients for a total of 88 measurements of bruises. Bili-skin values showed significant differences according to skin phototype. Differences between the bili-bruise and bili-skin values (Δ-bili) followed an increase phase, peaking between 3 and 5 days, and then there was a decrease phase. No significant Δ-bili value differences were observed based on the suspected confounding factors. Our results are in favour of a peak Δ-bili value generally at day 4 or 5 post-trauma. Notably, decreasing values were not observed before day 3. Decreasing Δ-bili values would then indicate a bruise resulting from an injury formed at least 3 days before the first measurement. Complementary work confirming such data would enable improvement of the performance of bruise dating in forensic medicine.