CT analysis of skull contents in naturally mummified human corpses, a multicentric study.

INTRODUCTION: This study aimed to assess skull contents, brain appearance, and density on postmortem computed tomography in naturally mummified corpses. MATERIAL AND METHODS: For this purpose, a retrospective multicentric study, including mummified corpses from two French centers (Brest and Nantes) and from the New Mexico Decedent Image Database (USA), was performed by analyzing postmortem computed tomography (PMCT) focused on the head and neck of partially or fully mummified corpses discovered between 2011 and 2022. The PMCT analysis provided data on the CT appearance of brains, allowing them to be classified into four different categories (desiccation, liquefaction, dura mater only (DMO), and absence), and to measure densities (HU) of the brain remains. In addition, data on postmortem intervals (PMI) from Nantes and Brest centers were collected and analyzed to test the link between brain densities and PMIs. RESULTS: 54 cases of naturally mummified corpses were included. The brains were classified as liquefied (56%), desiccated (17 %), DMO (20 %), and absent (7 %) based on their CT appearance. Dehydrated brains were significantly (p < 0.004) denser (median 102 HU, interquartile range (IQR) 41) than either liquefied brains (median 39.5 HU, IQR 9) or brains with DMO (median -25 HU, IQR 57). However, the density of brain remains was not significantly affected by where the bodies were found (p = 0,41). Analysis of PMI and brain densities was performed on 22 cases. The results showed that brain remains were significantly (p = 0.039) denser when they were found after a PMI of more than six months. CONCLUSION: Brain desiccation was the aspect with the highest densities on PMCT, and for which we were able to highlight great preservation of anatomical structures observable in living organisms.

Epidemiology and characteristics of firearm injuries in a French level I trauma centre, 2009-2019.

BACKGROUND: Firearm injuries (FI) are an increasing problem in Europe but there have been few European epidemiological studies on civilian FI, particularly in France. This study investigated the epidemiology of FI at a French level I trauma centre. METHODS: A retrospective cohort study was conducted of all patients admitted to our centre with an FI between January 2009 and December 2019. We investigated the epidemiological trends of FI during the study period, and characterised the FI. RESULTS: A total of 162 patients were victims of FI. Prevalence was 0.11% and the mean annual incidence was 10.4 per 100 000 habs. A significant increase has been observed over the last 10 years, from 5 cases in 2009 (3.1%) to 30 in 2019 (18.5%). Of the 162 victims, 85 (52.5%) died as a direct result of the FI: 72 suicides (88.9%) and 9 victims of urban violence (11.1%) (armed public environment disorder). 95.3% of the patients died before reaching at the hospital. There were 95 cases (58.7%) of suicide and 33 cases (20.4%) of urban violence. The head was shot in 87 cases (48.9%), the thorax in 32 cases (18.5%) and the lower limbs in 24 cases (13.5%). A total of 106 surgeries were performed on 54 patients (33.3%). CONCLUSIONS: We identified 162 cases of FI with a mean annual incidence of 10.4 per 100 000 habs. A significant increase in FI was observed over the last 10 years. 52.2% of patients died, and the main context was suicide or attempted suicide.

Feasibility of use of medical dual energy scanner for forensic detection and characterization of explosives, a phantom study.

OBJECTIVE: Detection of explosives is a challenge due to the use of improvised and concealed bombs. Post-bomb strike bodies are handled by emergency and forensic teams. We aimed to determine whether medical dual-energy computed tomography (DECT) algorithm and prediction model can readily detect and distinguish a range of explosives on the human body during disaster victim identification (DVI) processes of bombings. MATERIALS AND METHODS: A medical DECT of 8 explosives (Semtex, Pastex, Hexamethylene triperoxide diamine, Acetone peroxide, Nitrocellulose, Pentrite, Ammonium Nitrate, and classified explosive) was conducted ex-vivo and on an anthropomorphic phantom. Hounsfield unit (HU), electron density (ED), effective atomic number (Zeff), and dual energy index (DEI),were compared by Wilcoxon signed rank test. Intra-class (ICC) and Pearson correlation coefficients (r) were computed. Explosives classification was performed through a prediction model with test-retest samples. RESULTS: Except for DEI (p = 0.036), means of HU, ED, and Zeff were not statistically different (p > 0.05) between explosives ex-vivo and on the phantom (r > 0.80). Intra- and inter-reader ICC were good to excellent: 0.806 to 0.997 and 0.890, respectively. Except for the phantom DEI, all measurements from each individual explosive differed significantly. HU, ED, Zeff, and DEI differed depending on the type of explosive. Our decision tree provided Zeff and ED for explosives classification with high accuracy (83.7%) and excellent reliability (100%). CONCLUSION: Our medical DECT algorithm and prediction model can readily detect and distinguish our range of explosives on the human body. This would avoid possible endangering of DVI staff.

Contribution of dual-energy computed tomography in the differentiation of illicit drugs.

INTRODUCTION: The objective of this study was to compare the dual-energy behaviour of the main illicit substances as well as their cutting agents in order to be able to differentiate them. MATERIAL AND METHODS: Cocaine, heroin, MDMA, and cannabis as well as 3 adulterants, 2 diluents, and water were scanned at 90 kV and then at 140 kV on a single X-ray tube computed tomography (CT) scanner. The data acquired enabled a mapping of the attenuation values to 90 and 140 kVp as well as a resulting dual-energy index (DEI) mapping. RESULTS: Drugs, cocaine, MDMA (pill), and cannabis had a positive DEI (0.014-0.008), while heroin and MDMA (powder) had a negative DEI (-0.016 and -0.013). The DEI of water was -0.01 and that of taurine was -0.018. Adulterants had negative DEI, while diluents had a positive DEI. All DEI were significantly different (p < 0.01). CONCLUSIONS: Cocaine and heroin can be clearly differentiated using DEI.

Automated contour detection in spine radiographs and computed tomography reconstructions for forensic comparative identification.

This study was conducted to test an automated method to identify unknown individuals. It relies on a previous radiographic file and uses an edge-based comparison of lumbar CT/PMCT reconstructions and radiographs. The living group was composed of 15 clinical lumbar spine CT scans and 15 paired radiographs belonging to the same patients. The deceased group consisted of 5 lumbar spine PMCT scans and 5 paired antemortem radiographs of deceased individuals plus the 15 unpaired radiographs belonging to the living. An automated method using image filtering (anisotropic diffusion) and edge detection (Canny filter) provided image contours. Cross comparisons of all the exams in each group were performed using similarity measurements under the affine registration hypothesis. The Dice coefficient and Hausdorff distance values were significantly linked (p < 0.001 and p = 0.001 respectively) to the matched examinations in the living group (p < 0.001; pseudo-R2 = 0.70). 12 of the 15 examinations were correctly paired, 2 were wrongly paired and 3 were not paired when they must have been. In the deceased group, the Hausdorff distance was significantly linked (p = 0.018) to the matched examinations (p < 0.001; pseudo-R2 = 0.62; Dice coefficient p = 0.138). The paired examinations were all correctly found, but one was wrongly paired. The negative predictive value was above 98% for both groups. We highlighted the feasibility of comparative radiological identification using automated edge detection in cross-modality (CT/PMCT scan and radiographs) examinations. This method could be of significant help to a radiologist or coroner in identifying unknown cadavers.

Manual and Fully Automated Segmentation to Determine the Ferromagnetic Status of Bullets Using Computed Tomography Dual-Energy Index: A Phantom Study.

OBJECTIVE: The aim was to determine if dual-energy computed tomography (DECT) can discriminate ferromagnetic bullets from nonferromagnetic ones. METHODS: The ferromagnetic properties of 29 bullets were determined. All bullets underwent a DECT evaluation, and a manual measurement of the dual-energy index was performed by 2 radiologists, followed by a fully automatic measurement, in 3 different positions in a phantom (air, water, and bone). RESULTS: Twenty-one bullets were found to be nonferromagnetic. There were significant differences between the mean of the dual-energy index measured in the core of ferromagnetic projectiles and those of nonferromagnetic ones in the lung position of the phantom (P = 0.007). Specificity was 86.36%, and negative predictive value was 90.48%. Among the 29 bullets, 24 were correctly classified. CONCLUSIONS: Our study demonstrates that DECT can assess the ferromagnetic status of bullets and their magnetic resonance imaging compatibility using an extended computed tomography scale in an ex vivo phantom model.

Routine practice HCV infection screening with saliva samples: multicentric study in an intravenous drug user population.

OBJECTIVE: The purpose of this randomized multicentric study was to evaluate the diagnostic contribution of screening for HCV infection on saliva samples in day-to-day practice in the intravenous drug-user (IVDU) population. METHODS: Between January and May 2004, 274 presumably HCV-negative IVDU were screened for HCV infection in 15 centers in France (median age 29 years). After centralized randomization, screening tests were performed on blood samples (arm A) or saliva samples (arm B). Screening tests were performed in 78 subjects (28%) had never been screened before and in 196 subjects (72%) who had had a negative HCV screening test on average 12 months prior to the beginning of the study. In the event of a positive saliva test for anti-HCV Ab, a serum test for anti-HCV Ab was performed. In the event of a positive serum test for anti-HCV Ab, PCR was performed on serum to measure HCV-RNA. RESULTS: Fourteen individuals were positive for HCV RNA (7 in each arm). Six of these cases had not been detected before. In eight cases, the median time between the last negative screening test and study inclusion was 11 months (range 6-94 months). CONCLUSIONS: Viremia tests were positive in 5% percent of the target population, although one-third of the individuals in arm A (blood samples) were not tested. The saliva test may be a useful alternative in the event of refusal of a blood test or when poor venous conditions compromise venous puncture. A confirmatory blood test still remains difficult to obtain in nearly half of patients.