Virtual anthropology – a brief review of the literature and history of computed tomography

Computed tomography (CT) has influenced numerous fields since its inception in the 1970s. The field of palaeoanthropology significantly benefited from this efficient and non-invasive medium in terms of the conservation, reconstruction and analysis of fossil human remains. Over the past decade, there has been a steady increase in the number of forensic anthropological studies incorporating virtual osteological analyses. Because of the increasing importance of these modern cross-sectional imaging techniques and the requirement for standardized parameters in forensic science, we deemed it important to outline the history and development of CT applications in these related academic areas. The present paper outlines the history of “virtual anthropology” and osteological multi-detector CT in the context of palaeoanthropology and forensic anthropology

Gas analysis of exhumed cadavers buried for 30years: a case report about long time alteration

Due to important alteration caused by long time decomposition, the gases in human bodies buried for more than a year have not been investigated. For the first time, the results of gas analysis sampled from bodies recently exhumed after 30years are presented. Adipocere formation has prevented the bodies from too important alteration, and gaseous areas were identified. The sampling was performed with airtight syringes assisted by multi-detector computed tomography (MDCT) in those specific areas. The important amount of methane (CH4), coupled to weak amounts of hydrogen (H2) and carbon dioxide (CO2), usual gaseous alteration indicators, have permitted to confirm methanogenesis mechanism for long period of alteration. H2 and CO2 produced during the first stages of the alteration process were consumed through anaerobic oxidation by methanogenic bacteria, generating CH4

(210)Po poisoning as possible cause of death: forensic investigations and toxicological analysis of the remains of Yasser Arafat.

The late president of the Palestinian Authority, Yasser Arafat, died in November 2004 in Percy Hospital, one month after having experienced a sudden onset of symptoms that included severe nausea, vomiting, diarrhoea and abdominal pain and which were followed by multiple organ failure. In spite of numerous investigations performed in France, the pathophysiological mechanisms at the origin of the symptoms could not be identified. In 2011, we found abnormal levels of polonium-210 ((210)Po) in some of Arafat's belongings that were worn during his final hospital stay and which were stained with biological fluids. This finding led to the exhumation of Arafat's remains in 2012. Significantly higher (up to 20 times) activities of (210)Po and lead-210 ((210)Pb) were found in the ribs, iliac crest and sternum specimens compared to reference samples from the literature (p-value <1%). In all specimens from the tomb, (210)Po activity was supported by a similar activity of (210)Pb. Biokinetic calculations demonstrated that a (210)Pb impurity, as identified in a commercial source of 3MBq of (210)Po, may be responsible for the activities measured in Arafat's belongings and remains 8 years after his death. The absence of myelosuppression and hair loss in Mr Arafat's case compared to Mr Litvinenko's, the only known case of malicious poisoning with (210)Po, could be explained by differences in the time delivery-scheme of intake. In conclusion, statistical Bayesian analysis combining all the evidence gathered in our forensic expert report moderately supports the proposition that Mr Arafat was poisoned by (210)Po

Gas analysis of exhumed cadavers buried for 30 years: a case report about long time alteration.

Due to important alteration caused by long time decomposition, the gases in human bodies buried for more than a year have not been investigated. For the first time, the results of gas analysis sampled from bodies recently exhumed after 30 years are presented. Adipocere formation has prevented the bodies from too important alteration, and gaseous areas were identified. The sampling was performed with airtight syringes assisted by multi-detector computed tomography (MDCT) in those specific areas. The important amount of methane (CH4), coupled to weak amounts of hydrogen (H2) and carbon dioxide (CO2), usual gaseous alteration indicators, have permitted to confirm methanogenesis mechanism for long period of alteration. H2 and CO2 produced during the first stages of the alteration process were consumed through anaerobic oxidation by methanogenic bacteria, generating CH4

Dating human skeletal remains using a radiometric method: Biogenic versus diagenetic (90)Sr and (210)Pb in vertebrae.

In forensic science, there is a strong interest in determining the post-mortem interval (PMI) of human skeletal remains up to 50 years after death. Currently, there are no reliable methods to resolve PMI, the determination of which relies almost exclusively on the experience of the investigating expert. Here we measured (90)Sr and (210)Pb ((210)Po) incorporated into bones through a biogenic process as indicators of the time elapsed since death. We hypothesised that the activity of radionuclides incorporated into trabecular bone will more accurately match the activity in the environment and the food chain at the time of death than the activity in cortical bone because of a higher remodelling rate. We found that determining (90)Sr can yield reliable PMI estimates as long as a calibration curve exists for (90)Sr covering the studied area and the last 50 years. We also found that adding the activity of (210)Po, a proxy for naturally occurring (210)Pb incorporated through ingestion, to the (90)Sr dating increases the reliability of the PMI value. Our results also show that trabecular bone is subject to both (90)Sr and (210)Po diagenesis. Accordingly, we used a solubility profile method to determine the biogenic radionuclide only, and we are proposing a new method of bone decontamination to be used prior to (90)Sr and (210)Pb dating

GOP-29: The influence of scanner type and acquisition parameters on bone length measurements in computed tomography

Background and Aims. The purpose of this study was to examine the influence of the scanner type, reconstructed slice thickness and subjective image quality on precision of bone length measurements in multi-detector computed tomography (MDCT). Materials and Methods. Twenty dry long bones were scanned on two MDCT units, GE LightSpeed Ultra, 8 detector rows and GE LightSpeed VCT, 64 detector rows using reconstructed slice thickness of 0.625 and 1.25 mm. Four observers evaluated the subjective image quality and maximum bone length. Conventional caliper bone length measurements served as ground truth. Results and Conclusions. Measurements on the 64-row scanner were more precise than on the 8-row scanner. However, slice thickness did not seem to have any effect on the precision of measurements. Nevertheless, differences are small and may be correlated to minimal physical detector resolution in the Z-axis. Subjective image quality was best at the 64-row scanner with 0.625 mm reconstructed slice thickness (full-isotropy) and worst at the 64-row scanner with 1.25 mm (anisotropy). The depiction of small structures such as trabecular bone was best at isotropic voxel size. Subjective image quality had no influence on bone length measurement precision

Evaluating Preoperative Models: A Methodologic Contribution.

Three-dimensional (3D) printed models of the human skull and parts of it are being increasingly used for surgical education and customized preoperative planning. This study, using the calvaria as a model, provides a methodologic analysis with regard to future investigations aimed at evaluating patient-specific skull replicas. Postmortem computed tomography was used for 3D reconstruction of a skull. The digital model obtained was converted to a physical replica by 3D printing. This copy was compared qualitatively and quantitatively with the original, using both a classical anthropometric and a 3D surface scanning approach. Qualitatively, the replica and the original displayed good qualitative concordance. The quantitative deviations, as measured by osteometric tools, lay partly in the submillimetric area, partly between 1 and 2 mm. The maximum difference was 3.7 mm. On the basis of the surface scans, a mean deviation of 0.2930 mm (±0.2677 mm) and a median difference of 0.2125 mm (0.0000-1.5509 mm) were observed for the inner surface. For the whole object, corresponding figures amounted to 0.9101 mm (±0.5390 mm) and 0.8851 mm (0.000-3.2647 mm). Qualitatively flawless replicas of the skull region investigated are feasible, subject to extensive manual CT image editing. However, neurosurgeons should be aware that models of one and the same patient will vary according to the production chain used by the 3D printing laboratory in charge. Methodologically, both classic anthropological and light-stripe-based comparisons are justified for use in future studies. For trials aimed at assessing mean deviations and topographic distribution patterns, optical 3D scanning technologies can be recommended