Le Garff Erwan, Mesli Vadim, Delannoy Yann, Colard Thomas, Demondion Xavier, Becart Anne, Hedouin Valéry
Univ. Lille, EA 7367 - UTML - Unité de Taphonomie Médico-Légale, Rue André Verhaeghe, 59000, Lille, France.
Int J Legal Med. 2017 May;131(3):761-770. doi: 10.1007/s00414-016-1509-y. Epub 2016 Dec 29.
Post-mortem interval (PMI) estimation is an important issue in forensic medicine, particularly for criminal purposes and legal limitation periods. The goal of the present study is to examine the evolution of the trabecular cranial vault bone after 4 weeks of conservation in a controlled environment with micro-tomography (μCT) analyses.Four bone samples were extracted from a fresh human cranial vault (a donation to science according to the French law) and conserved in an air-controlled environment. The samples were weighed and μCT scanned at a 10-μm resolution every week after death for a month. The μCT features were identical for every sample. Each set of data from the μCTs was reconstructed, registered, and analyzed in terms of the total volume, bone volume, bone surface, number of trabeculae, trabeculae thickness, and mean distance of the trabeculae. The samples were conserved in a glass box in 20 °C air with 60% humidity in a laboratory hood between each μCT acquisition. Descriptive statistics were determined. Each sample was observed and compared to itself over time.After 1 month of conservation, the mean bone volume (-1.9%), bone surface (-5.1%), and trabecular number (-12.35%) decreased, whereas the mean trabecular separation (+5.55%) and trabecular thickness (+12.7%) increased. Many variations (i.e., increases and decreases) were observed between the extraction of the sample and the end of the 4 weeks of conservation. The present observations may be explained by bone diagenesis. Previous observations have indicated that protein and lipid losses occur with bone weight and volume losses. These diagenesis effects may explain the trabecular modifications observed in the present work. We observed many bone variations with the μCT scans between the beginning and the end of the conservation that had no explanations. Additional studies, particularly studies involving statistics, need to be performed to confirm our observations and explain these results more clearly.
死后间隔时间（PMI）的估计是法医学中的一个重要问题，特别是在刑事目的和法定时效方面。本研究的目的是通过显微断层扫描（μCT）分析，研究在可控环境中保存4周后颅顶骨小梁的演变情况。从新鲜的人类颅顶骨中提取了四个骨样本（根据法国法律捐赠给科学），并保存在可控空气环境中。样本称重后，在死后每周以10微米的分辨率进行μCT扫描，持续一个月。每个样本的μCT特征相同。对μCT的每组数据进行重建、配准，并从总体积、骨体积、骨表面积、小梁数量、小梁厚度和小梁平均距离等方面进行分析。在每次μCT采集之间，样本保存在实验室通风橱内的玻璃盒中，温度为20°C，空气湿度为60%。确定了描述性统计数据。对每个样本进行观察，并随时间进行自身比较。保存1个月后，平均骨体积（-1.9%）、骨表面积（-5.1%）和小梁数量（-12.35%）减少，而平均小梁间距（+5.55%）和小梁厚度（+12.7%）增加。在样本提取和4周保存结束之间观察到许多变化（即增加和减少）。目前的观察结果可能由骨成岩作用来解释。先前的观察表明，蛋白质和脂质损失伴随着骨重量和体积的损失。这些成岩作用效应可能解释了本研究中观察到的小梁变化。我们通过μCT扫描观察到保存开始和结束之间有许多骨变化，但无法解释。需要进行更多的研究，特别是涉及统计学的研究，以证实我们的观察结果并更清楚地解释这些结果。
