Intra-class and inter-class tool discrimination through micro-CT analysis of false starts on bone.

Micro-CT has successfully been applied to the characterization of false starts (FSs) and, among several parameters, kerf width seems to correlate to the tool blade. The aim of the present study was to evaluate the diagnostic value of micro-CT for the differentiation of saw marks produced by different classes of saws and by saws belonging to the same class and differing only in number of teeth per inches (TPI). A morphological and morphometric analysis of 84 marks, produced by 6 saws belonging to 3 morphological classes, was performed. In the experimental cohort, for each parameter, statistically significant differences in intra- and inter-class analysis were searched for and cut-offs were established. The diagnostic accuracy of cut-offs was assessed through statistical analyses on the validation cohort. The morphological assessment did not allow to differentiate saws differing only in TPI. Angle 1 and top kerf width, respectively for cross-cut and rip-cut saws with alternating set, allowed a good discrimination between FSs produced by tools belonging to the same morphological class. High positive predictive values were found in intra-class analyses, while results in inter-class analyses were less encouraging. In cases of dismemberment, a micro-CT-based analysis of FSs is strongly suggested as a part of a multistep and multimodal methodology of assessment, which includes scanning electron microscopy and stereomicroscopy. A morphological assessment should be followed by an experimental trial and by a morphometric analysis. Further studies are needed to evaluate hampering factors, such as damage by physico-chemical agents.

Radiological investigation of gunshot wounds: a systematic review of published evidence.

INTRODUCTION: Despite the constantly growing popularity of radiological imaging in forensic pathology, a systematic review investigating the efficiency and limits of radiological techniques, in comparison to forensic autopsy, was still missing. AIM: The present review aims at providing an overview on the current role of radiology in the forensic investigation of fatal gunshot wounds without any restriction to specific radiological techniques. MATERIAL AND METHODS: A systematic literature search on three databases (PubMed, Web of Science, and Science Direct) was performed until December 2017. The Oxford Centre for Evidence Based Medicine (OCEBM) grading system for levels of evidence was applied, in order to weigh published evidence. RESULTS AND DISCUSSION: Eighty-six papers (1.64% of the records) were included. Despite the quite limited general level of evidence, which contrasts with the abundance of the scientific literature on this topic, several recommendations/statements, coupled to their OCEBM grade, were distilled as for the identification of retained bullets, gunshot wounds detection, diagnosis of entrance and exit wounds, trajectories and internal injury detection and estimation of the firing distance. CONCLUSIONS: Imaging radiological technologies represent the present and future of wound ballistics. However, traditional, micro and molecular imaging techniques require further validation through blinded cross-sectional studies with appropriate reference standards (e.g. forensic autopsy).