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The forensic investigation of a deceased person retrieved following a fire includes measuring carboxyhemoglobin. A carboxyhemoglobin saturation above 10% is considered indicative of respiration during a fire, implying the person had been alive. This relies on the assumption that carbon monoxide will not diffuse into blood used for toxicological analysis. This project investigated the potential for carbon monoxide to passively diffuse into a body and if carboxyhemoglobin levels could become elevated post-mortem. Stillborn piglets with intact skin were exposed to carbon monoxide. Carboxyhemoglobin formed in the hypostasis of the skin, but carboxyhemoglobin levels in blood from the heart and chest cavities were not significantly elevated. However, defects in the skin over body cavities (producing breaches to replicate cases with stab wounds or heat damage) resulted in cavity blood carboxyhemoglobin levels above 10%. A review of fire death cases in South Australia 2000-2015 was performed to determine the origin of the blood samples used for toxicological analysis and the incidence of cases with breaches of body cavities. This revealed a small number of cases in which blood from the cavities had been analyzed when cavity breaches were present. Thus, there is a potential for significant elevation of carboxyhemoglobin saturation post-mortem in forensic casework involving bodies retrieved from fires.

Summary Aims Biochemical analysis of glucose and ketones in the vitreous humour obtained at post-mortem examination is representative of the levels in the blood prior to death. Elevated levels can be indicative of conditions including diabetic ketoacidosis, which can be a cause for unexpected death. A rapid screening test for such conditions can be performed during the autopsy through urinalysis using test strips (urine ‘dipstick’ testing). The aim of this study was to assess the utility of urinalysis testing for post-mortem detection of derangements of glucose and ketone levels. Methods The results of vitreous biochemical analysis and urinalysis were collated from 188 forensic autopsy cases. Results A vitreous glucose result of above 10mmol/L was regarded as high. When this was compared to urinalysis results it was found that any urinalysis result above negative had a sensitivity of 0.83 and a specificity of 0.93. A vitreous ketone level of above 5 mmol/L was regarded as significantly elevated; a urinalysis result above negative had a sensitivity of 1, but a specificity of 0.12. Conclusions Urinalysis (‘dipstick’ testing) for glucose has a good sensitivity and specificity for high vitreous glucose levels, which are regarded as indicative of pathological hyperglycaemia during life. It was found that urine testing for ketones either has an excellent sensitivity with low specificity or a poor sensitivity with a good specificity; however, this finding has to be viewed in the context of uncertainty of the biochemical level of significant ketosis.

Aim Evaluate the use of MRI to detect the accumulation of hemo-siderin in bruises and assess if this information can be applied to estimate the age of a bruise. Methods A low trauma animal model of a bruise was established for the investigation of hemosiderin deposition. T1 weighted sequence scans were performed on the bruised tissue sections within a 16.4T MRI. The scanned sections were then histologically stained using Perls’ Prussian blue for hemosiderin to compare with the MRI findings. Results Hemosiderin visualised within the Perls’ Prussian blue staining as blue spotting was seen to correspond with dark areas seen within the T1 sequences obtained from the 16.4T MRI. Discussion Hemosiderin is produced from the breakdown of blood in a bruise; it can be readily demonstrated in histological sections using the Perls’ Prussian blue stain and its presence can be used to infer a bruise is not recent. A non-invasive method to investigate this is provided by magnetic resonance imaging (MRI). This study demonstrated that MRI could be used to visualise bruises and that such a technique may have the potential to help estimate the age of a bruise.

Introduction Hyperspectral imaging combines a camera with a tunable optical filter to record reflectance spectrophotometry data over a range of wavelengths for each image point. The data can be mathematically processed. Bruises comprise extravasated blood (haemoglobin) in the skin that is broken down to haemosiderin and bilirubin, the presence of which can be demonstrated by analysis of hyperspectral data. Aims To develop hyperspectral image data processing to demonstrate the spatial distribution of bruises and their temporal changes. Method Bruise-type injuries were created by injection of blood into skin of rats (with Animal Ethics Approval 1 ). Hyperspectral images were captured using a Chemimage HSI examiner 100 QD at a range of time points. Hyperspectral data were processed to analyse the first derivative to quantify the accumulation of degradation products of haemoglobin; tissue was also examined histologically. Results Hyperspectral images were successfully obtained; however, initial processing did not provide a defined correlation with time or histological changes. Discussion Initial results using simple analysis of first derivative values did not produce a clear correlation with accumulation of haemoglobin degradation products over time. Advanced processing techniques will be tested and the outcome of these will be presented.

This brief presentation will provide an illustrated guide on how to remove the intraosseous component of the internal carotid arteries and the middle ears for examination.

This will be a quiz session using the audience response keypads that have been funded by the Royal College of Pathologists of Australasia (RCPA) through the provision of Specialist Training Programme (STP) grants by the Australian Government Department of Health and Ageing (DoHA). This will allow anonymous answers to be collected and informative feedback provided for each question as the quiz progresses.