Postmortem Computed Tomography Data Research Articles

Significance of intracranial gas on post-mortem computed tomography in traumatic cases in the context of medico-legal opinions

The detection of intracranial gas (ICG) in people who died due to trauma became possible once postmortem computed tomography (PMCT) became available in addition to traditional post-mortem examinations. The aim of this study was to determine the importance of ICG in the context of medico-legal opinions. We assessed 159 cases of trauma-induced death. Cadavers with pronounced signs of decomposition, open skull fractures, and after neurosurgical operations were excluded. Both PMCT findings and data from autopsy reports were analyzed. ICG was found in 38.99% (n = 62) of the cadavers, 96.77% (n = 60) of which presented with pneumocephalus (PNC) and 40.23% (n = 25) with intravascular gas (IVG). There was a strong correlation between ICG and skull fractures/brain injuries, as well as chest injuries, especially lung injuries. In 13 cases, ICG presented without skull fractures; three of these cases died as a result of stab and incised wounds to the neck and chest. The mean time between trauma and death was significantly longer in the non-ICG group than the ICG group at 2.94 days (0–48 days) and 0.01 day (0–1 day), respectively (p < 0.0001). The presence of ICG is a result of severe neck and chest injuries, including stab and incised wounds. The victims die in a very short amount of time after suffering trauma resulting in ICG. The ability to demonstrate ICG on PMCT scans can be of significance in forming medico-legal opinions.

Post-mortem computed tomography (PMCT) radiological findings and assessment in advanced decomposed bodies.

The aim of the study is to report radiological findings and features in advanced decomposed bodies obtained by post-mortem computed tomography (PMCT) with autopsy correlation. This retrospective descriptive multicentric study included 41 forensic cases examined between May 2013 and November 2016. All the bodies were PMCT-scanned prior to autopsy, and internal putrefactive state was determined using the radiological alteration index (RAI) by a radiologist with expertise in forensic radiology and a forensic pathologist trained in forensic imaging. After PMCT scans, grade of external putrefaction (GEP) was assigned during the external examination and the complete autopsy was performed by forensic pathologists. The PMCT images evaluation revealed that the RAI index was > 61 in all bodies, corresponding to a moderate-massive presence of putrefactive gas. The gas grade was > II in correspondence of the major vessels, heart cavities, liver parenchyma, vertebra L3 and subcutaneous pectoral tissues, and varied from I to III in correspondence of the kidney. Cadaveric external examination revealed the presence of advanced transformative phenomena, with a GEP3 and GEP4 in most of the cases, with body swelling, eyes and tongue protrusion, body fluids expulsion and fat liquefaction. Radiological imaging by PMCT as an adjunct to autopsy in advanced decomposed bodies represents a useful tool in detecting post-mortem gas, even in very small amounts. A correct interpretation process of the PMCT data is essential to avoid images pitfalls, due to natural decomposition that can be mistaken for pathologic processes.

Approaching pulmonary fat embolism on postmortem computed tomography.

Pulmonary fat embolism (PFE) is a relevant diagnosis playing a role as a sign of vitality or a cause of death. Its severity is assessed according to histological grading systems like that of Falzi. The aim of this study was to determine the utility of unenhanced postmortem computed tomography (PMCT) for PFE diagnosis based on the detection of fat layers. Consecutive cases with PMCT and autopsy were studied retrospectively. The case group consisted of cases with positive PFE, and the control group included cases with negative PFE. Three observers independently assessed PMCT data for fat layers in the pulmonary trunk and the right and left pulmonary artery. For cases with fat layers, autopsy protocols were assessed for the cause of death, relation to trauma, and undertaken resuscitation measures. Eight hundred thirty cases were included: 366 PFE positive cases (144 of Falzi grade 1, 63 of 1.5, 99 of 2, 28 of 2.5, and 32 of 3) and 464 PFE negative cases. Interrater reliabilities varied between substantial and almost perfect, and discrepancies were solved according to majority. Eighteen cases showed fat layers on PMCT (2 controls-traumatic instantaneous deaths-, 16 PFE positive cases). PMCT showed low sensitivity but high specificity for PFE diagnosis. The layers were located at the same position in the pulmonary trunk directly adjacent to the pulmonary valve distal to the right ventricle. Fat layer on PMCT is a rare finding but relates to PFE diagnosis, especially of severe histological grade. It is to be expected in a typical position within the pulmonary trunk.

Analysis of cases of traumatic pneumothorax - conclusions based on post-mortem CT examinations for routine autopsy diagnostics

The analysis comprised atotal of 450 cases covering the period 2017-2018, in which death was aresult of traffic accident, fall from aheight, and crushing. Post-mortem examinations carried out at the Department of Forensic Medicine in Krakow consisted of conventional autopsy and post-mortem computed tomography (PMCT). The aims of the study were to evaluate the prevalence of pneumothorax in the study group, and attempt to identify acorrelation between pneumothorax and the presence of specific types of thoracic injuries and the circumstances of trauma. Based on the PMCT data, pneumothorax was detected in 43% of cases in the study group. An important finding was the presence of tension pneumothorax with lung collapse and mediastinal shift in 16% of cadavers in the study group. The main injuries accompanying pneumothorax were found to be fractures of the rib cage (ribs, sternum, spine) and lung injuries. In 20% of cases, pneumothorax was shown to coexist with subcutaneous emphysema. In 11% of cases, marked asymmetry of the chest was noted. The circumstances of trauma resulting in the accumulation of air in the pleural cavities included primarily falls from aheight and hits by avehicle.

Death by hanging: a retrospective case-control investigation of the intervertebral disc vacuum phenomenon on PMCT.

During hanging gravitational forces affect the spine. Intervertebral vacuum phenomenon (VP) implies that gas accumulations in the discs are caused by degeneration of the spine and trauma. It was hypothesized that VP detected on postmortem computed tomography (PMCT) has a higher incidence in hanging deaths, which can be correlated to age, degenerative spinal changes and type of hanging (complete-incomplete). Secondly, it was investigated whether the presence of Simon's bleedings is related to hanging type and VP on PMCT. A retrospective hanging case-control study of 72 cases was conducted. PMCT data were evaluated by two observers for the presence of VP and its localization within the thoracic and lumbar discs, and for any degenerative changes of the spine. Autopsy protocols were assessed for the presence of Simon's bleedings during autopsy. VP did not statistically differ among hanging and control cases but it was statistically correlated to complete hanging, increasing age and degenerative spinal changes. Centrally located VP within the discs was correlated to hanging, especially complete hanging, and younger ages, contrary to control cases that showed gas at the disc periphery. Simon's bleedings were correlated with complete hanging and centrally located VP. Centrally located VP within the discs increases the probability for complete hanging, while increasing age and degenerative changes reduce this probability. Intervertebral VP is multifactorial radiological entity. The presence of centrally located VP can indicate that hanging could be considered as an alternative mechanism of death and that great forces and loads may have affected the spine perimortem, especially with decreasing age and when Simon's bleedings are present.

Classification based on the presence of skull fractures on curved maximum intensity skull projections by means of deep learning

Abstract Objectives Postmortem computed tomography (PMCT) usually includes the generation of great amounts of imaging data, and is often reviewed by forensic pathologists. To allow a more resource-efficient diagnosis, deep neural networks may act as a pre-scanning tool in postmortem radiology. In this study, a deep neural network to classify cases depending on the presence skull fractures on curved maximum intensity projections (CMIP). Methods Calvarial CMIPs of each 75 cases with and without documented skull fractures were retrospectively generated from our database. Then, half of the data were randomly assigned to either training or validation. In supervised training, fractures were manually marked. During validation, each image received a gradual score between 0 and 1 predicting the likelihood of showing one or more fractures. Results With a total number of 100 networks trained, the average area under the Receiver Operating Characteristic curve (AUC) was 0.895. The best performing network had an AUC of 0.965. At a classification threshold of 0.79, the network classified fracture cases correctly with a sensitivity of 91.4% and a specificity of 87.5%. Conclusion Classification based on the existence of skull fractures on CMIPs with deep learning is feasible. For the purpose of pre-scanning PMCT data, a classification threshold of 0.75 with a sensitivity of 100% can be applied. A higher number of images of validated skull fractures available will increase the performance of the network. In the future, Deep learning might enable a more resource-efficient assessment in postmortem radiology.

Contrast-enhanced cadaver-specific computed tomography in gross anatomy teaching.

To establish contrast-enhanced (CE) cadaver-specific post-mortem computed tomography (PMCT) in first-year gross anatomy teaching and quantitatively evaluate its learning benefit. 132 first-year medical students were included in this IRB-approved study and randomly assigned to an intervention group (n=59) provided with continuous access to CE and non-enhanced (NE) cadaver-specific PMCT-scans during the first-semester gross anatomy course, and a control group (n=73) that had only NE cadaver-specific PMCT data available. Four multiple-choice tests were carried out (15 questions each) subsequent to completion of the corresponding anatomy module: Head and neck anatomy, extremities, thorax, and abdomen. Median test results were compared in each module between the groups using the Wilcoxon rank-sum test. Additionally, participants of the intervention group answered a 15-item feedback-questionnaire. The intervention group achieved significantly higher test scores in head and neck anatomy (median=12.0, IQR=10.0-13.0) versus the control group (median=10.5, IQR=9.0-12.0) (p<0.01). There were no significant differences in the comparison of other modules. CEPMCT was highly appreciated by undergraduate medical students. The incorporation of contrast-enhanced cadaver-specific PMCT-scans in gross anatomy teaching was proven to be feasible in the framework of the medical curriculum and significantly improved the students' learning performance in head and neck anatomy. • Cadaver-specific contrast-enhanced post-mortem CT (CEPMCT) is feasible in the medical curriculum. • CEPMCT yields significantly improved learning performance in head and neck anatomy (p<0.01). • CEPMCT is highly appreciated by medical students and used in tutor- or self-guided modes.

Virtual computed tomography morphometry of the patella for estimation of sex using postmortem Japanese adult data in forensic identification

In forensic anthropological identification of human remains and single bones, computed tomography (CT) data analysis facilitates volumetric and radiographic density analyses, and a recently developed automated analysis system markedly improved the performance, accuracy, and reproducibility of three-dimensional (3-D) reconstruction. The present study aimed to investigate virtual CT morphometry of the patella for the estimation of sex using postmortem CT data of forensic autopsy cases of Japanese individuals aged ≥18 years (total n=220; 110 males and 110 females; estimated postmortem interval <88h), especially with regard to the efficacy of 3-D bone volumetry. Sex-related differences were detected for all parameters (males>females; p<0.0001), but the differences were the most notable for bone mass volume; the estimated cut-off values (cm3) for discriminating males and females were 20.35 with a sensitivity and specificity of 0.85 and 0.91 for the left side and 19.96 with a sensitivity and specificity of 0.83 and 0.92 for the right side, respectively. The mean CT value showed an age-dependent decrease and was particularly low in females aged >60years. These findings indicate the efficacy of virtual CT morphometry of the patella using an automated analyzer for sex estimation.

Post-mortem CT: Hounsfield unit profiles obtained in the lungs with respect to the cause of death assessment.

Segmentation of the lungs using post-mortem computed tomography (PMCT) data was so far not feasible due to post-mortem changes such as internal livores. Recently, an Osirix plug-in has been developed allowing automatically segmenting lungs also in PMCT data. The aim of this study was to investigate if the Hounsfield unit (HU) profiles obtained in PMCT data of the segmented lung tissue present with specific behaviour in relation to the cause of death. In 105 PMCT data sets of forensic cases, the entire lung volumes were segmented using the Mia Lite plug-in on Osirix. HU profiles of the lungs were generated and correlated to cause of death groups as assessed after forensic autopsy (cardiac death, fatal haemorrhage, craniocerebral injury, intoxication, drowning, hypothermia, hanging and suffocation). Especially cardiac death cases, intoxication cases, fatal haemorrhage cases and hypothermia cases showed very specific HU profiles. In drowning, the profiles showed two different behaviours representing wet and dry drowning. HU profiles rather varied in craniocerebral injury cases, hanging cases as well as in suffocation cases. HU profiles of the lungs segmented from PMCT data may support the cause of death diagnosis as they represent specific morphological changes in the lungs such as oedema, congestion or blood loss. Especially in cardiac death, intoxication, fatal haemorrhage, hypothermia and drowning cases, HU profiles may be very supportive for the forensic pathologist.

Utilitarian Aspects of Postmortem Computed Tomography

Computed tomography has been used in clinical medicine for decades, but only recently introduced into the forensic pathology setting. The reasons for the slow adoption of this technology into the autopsy suite are various, including concerns about funding, infrastructural maintenance, training, competency, and scope of utilization. Practical experience in a busy statewide medical examiner department confirmed the utility of this technology as a part of daily practice. The impact of postmortem computed tomography (PMCT) on casework can be stratified into three broad groups: where PMCT 1) supplants invasive autopsy, 2) supplements invasive autopsy, or 3) has limited or no potential for impact on practice. A detailed understanding of the practical uses of this science is important for the practicing forensic pathologist so as to guide decisions about the ways in which PMCT can be implemented within their own institutions and utilized on a daily basis. Dramatic changes in personal and institutional practice trends can be observed once forensic pathologists are comfortable with the evaluation, documentation, and interpretation of PMCT data. Examples of potential paradigm shifts include the performance of only external examination and PMCT instead of invasive autopsy in many cases of motor vehicle fatalities, suicide with violence, and broad categories of death due to natural disease. Over time, the authors believe that the PMCT will become one of the fundamental tools in the forensic pathologist's toolkit.

Identification of a jawless skull by superimposing post-mortem and ante-mortem CT

Abstract A jawless skull was found in a mountain area during a murder investigation. The skull was thought to belong to a missing male person who had been killed and buried in the area 2 years before. The body could not be identified from fingerprints or dental records since the offenders amputated both his hands and destroyed his jaws. We tried to identify the skull based on antemortem (AM) computed tomography (CT) images of the missing person and the postmortem (PM) CT data of the skull by superimposing the two data sets using imaging software both in two dimension (2D) and three dimension (3D). The results suggested that the two data sets were significantly identical in shape and size by both multi-planar reconstruction (MPR) and 3D volume rendering (VR). We succeeded in identifying the subject using PM CT data of the skull without the jaws and comparing those data with AM CT data of the head. This method is very easy to apply, and its results are far more compelling than other anthropological methods when shown in court to medical non-professionals.

Virtual CT morphometry of lower limb long bones for estimation of the sex and stature using postmortem Japanese adult data in forensic identification

The application of computed tomography (CT) is useful for the documentation of whole-body anatomical data on routine autopsy, virtual reconstruction of skeletal structure, objective measurements, and reassessment by repetitive analyses. In addition, CT data processing facilitates volumetric and radiographic density analyses. Furthermore, a recently developed automated analysis system markedly improved the performance and accuracy of three-dimensional (3D) reconstruction. The present study investigated virtual CT morphometry of lower limb long bones, including the femur, tibia, fibula, and first metatarsus, to estimate the sex and stature using postmortem CT data of forensic autopsy cases of Japanese over 19 years of age (total n = 259, 150 males and 109 females). Bone mass volumes, lengths, and total CT attenuation values of bilateral femurs, tibias, and fibulas correlated with the stature; however, the mean CT attenuation (HU) values showed age-dependent decreases. Correlations with the stature were similar for the lengths and mass volumes of the femur, tibia, and fibula (r = 0.77-0.85) but were higher for the mass volume of the first metatarsus (r = 0.77 for right and r = 0.58 for left). In addition, the ratio of the bone volume to the length of each bone showed the most significant sex-related differences (males > females with accuracy of 75.8-98.1 %). These findings indicate the usefulness of virtual CT morphometry of individual lower limb long bones, including volumetry, to estimate the sex and stature in identification.

The correlation of epicardial adipose tissue on postmortem CT with coronary artery stenosis as determined by autopsy.

The goal of this study was to assess whether epicardial and paracardial adipose tissue volumes, as determined by computed tomography (CT), correlate with coronary artery stenosis as determined by autopsy. The postmortem CT data and autopsy findings of 116 adult human decedents were retrospectively compared. Subjects were classified into three groups according to their degree of coronary artery stenosis: ≥50, <50%, and no stenosis. Epicardial and paracardial adipose tissue volumes were calculated based on manual segmentation after threshold based masking. In addition, epicardial adipose tissue thickness was measured using a caliper. All three parameters (thickness of epicardial fat and volumes of both epicardial and paracardial fat) were compared among the three groups and correlated with the degree of coronary artery stenosis. The group with no coronary artery stenosis showed the lowest mean values of epicardial adipose tissue volume, while the coronary artery stenosis ≥50 % group showed the highest volume. All measured variables (thickness of epicardial fat and volumes of both epicardial and paracardial fat) correlated significantly with the grade of coronary artery stenosis, even after controlling for BMI, however, epicardial adipose tissue volume exhibited the strongest correlation. This study reveals that there is an association between the degree of coronary artery stenosis and the amount of epicardial fat tissue: The larger the volume of epicardial fat, the higher the degree of coronary artery stenosis.

Can ruptured abdominal aortic aneurysm be accurately diagnosed as the cause of death without postmortem computed tomography when autopsies cannot be performed?

PurposeThis study aimed to conduct a multicentre retrospective review of cases to clarify how many ruptured abdominal aortic aneurysms (RAAAs) as the cause of death could be diagnosed without post-mortem computed tomography (PMCT) when autopsies cannot be performed. MethodsWe collected consecutive PMCT data from January 2002 to December 2009 from three institutes where PMCT examinations are performed on a routine basis for deceased patients with unknown causes of death. A total of 19 cases were identified where PMCT revealed RAAAs. Ante-mortem clinical presentations, post-mortem external examinations, and peri-mortem ultrasonography findings were assessed for their diagnostic accuracy. ResultsThe correct diagnosis based on the classic triad of shock, acute abdominal pain, and pulsatile abdominal mass was made in only one of 19 (5.3%) patients. Shock, acute abdominal pain, and abdominal swelling were found in five of 19 (26%) patients. Shock and acute abdominal pain or abdominal swelling were found in two of 19 (10%) patients. Ten of 19 (53%) patients only had shock. Peri-mortem ultrasonography was performed in seven of 19 patients; one was diagnosed with RAAA (14%). No patients had pre-mortem CT examinations. ConclusionsPost-mortem diagnosis of RAAA is difficult to make based on ante-mortem clinical presentation, post-mortem external examinations, or peri-mortem ultrasonography. PMCT is recommended for diagnosing RAAA as the cause of death if pre-mortem CT examinations are not carried out when autopsies cannot be performed.

1.7. Use of radiopaque markers in reconstruction of gunshot injuries

Objectives The identification of the trajectory of a projectile through the body is one of the most important issues to be solved in any case of gunshot injuries. Despite the advancements in modern cross-sectional imaging techniques those injuries still pose a challenge in forensic investigation. The exact identification of the entry and exit wound on the body surface, which is of great importance for the reconstruction of events, can be challenging on postmortem computed tomography (PMCT). This fact gives raise to requirement for an additional and highly reliable assisting technique. In response, a simple system was used, which adds information on entry and exit wound to standard PMCT images. Material and method A radiopaque rubber-seal ring was selected for external marking of gunshot wounds. It was placed around the wound and adhered to the body with double sided tape. A whole-body PMCT scan was performed after this preparation. Each ring was visible on the cross-sectional images surrounding the body surface wound, with the skin defect located centrally, and served as a permanent record of the anatomical location of the wound. Results This method has proven to be a quick and easy procedure for locating body surface gunshot wounds on PMCT scans. In contrast to other methods proposed for this purpose, this technique profits from higher accuracy and is non-invasive. The determination of the center of the rings allowed for identification of the entry and exit wound defects, contributing to the reconstruction of the injury. Conclusion The need for an accurate and simple method for marking entry and exit gunshot wounds was addressed yielding good results. It aids the initial investigation of gunshot injuries, as well as enables the three-dimensional visualization of acquired PMCT data.

Efficacy of automated three-dimensional image reconstruction of the femur from postmortem computed tomography data in morphometry for victim identification

Besides conventional radiology, postmortem computed tomography (PM-CT) is nowadays widely used for victim identification in forensic routines to detect anatomical characteristics and specific pathologies as well as to estimate the stature and sex. A major advantage of PM-CT is virtual reconstruction of skeletal structures independent of the status of recovered remains. The present study investigated the efficacy of a recently provided automated analyzer to reconstruct three-dimensional (3-D) images using CT data for skeletal morphometry, measuring the whole bone mass volume of the femur (60 bones in 30 cases) as an index of reproducibility. Manual cursoring could reconstruct bilateral femurs with high reproducibility, showing mass volume fluctuations by repetition and between two independent observers of 0.2-2.1% and 3.5-6.7%, respectively, partly depending on the data analysis system, but was time-consuming, while automated reconstruction was very rapid and highly reproducible virtually without detectable fluctuation; there was a high correlation between bone mass volumes reconstructed by manual and automated procedures (r=0.9976, p<0.0001). The reproducibility of the automated procedure was 98.64-100.81% in 5 cases scanned twice under the same CT conditions. Preliminary analysis showed a substantial correlation of the whole femur mass volume with the body height and a significant sex-related difference in the femur mass volume/body height ratio (males>females). These findings indicate the accuracy and practical feasibility of the automated procedure to reconstruct single bone 3-D CT images for virtual skeletal morphometry in victim identification.

Cardiothoracic ratio in postmortem computed tomography: reliability and threshold for the diagnosis of cardiomegaly

The aim of this study was to evaluate the reliability of the cardiothoracic ratio (CTR) in postmortem computed tomography (PMCT) and to assess a CTR threshold for the diagnosis of cardiomegaly based on the weight of the heart at autopsy. PMCT data of 170 deceased human adults were retrospectively evaluated by two blinded radiologists. The CTR was measured on axial computed tomography images and the actual cardiac weight was weighed at autopsy. Inter-rater reliability, sensitivity, and specificity were calculated. Receiver operating characteristic curves were calculated to assess enlarged heart weight by CTR. The autopsy definition of cardiomegaly was based on normal values of the Zeek method (within a range of both, one or two SD) and the Smith method (within the given range). Intra-class correlation coefficients demonstrated excellent agreements (0.983) regarding CTR measurements. In 105/170 (62 %) cases the CTR in PMCT was >0.5, indicating enlarged heart weight, according to clinical references. The mean heart weight measured in autopsy was 405 ± 105 g. As a result, 114/170 (67 %) cases were interpreted as having enlarged heart weights according to the normal values of Zeek within one SD, while 97/170 (57 %) were within two SD. 100/170 (59 %) were assessed as enlarged according to Smith's normal values. The sensitivity/specificity of the 0.5 cut-off of the CTR for the diagnosis of enlarged heart weight was 78/71 % (Zeek one SD), 74/55 % (Zeek two SD), and 76/59 % (Smith), respectively. The discriminative power between normal heart weight and cardiomegaly was 79, 73, and 74 % for the Zeek (1SD/2SD) and Smith methods respectively. Changing the CTR threshold to 0.57 resulted in a minimum specificity of 95 % for all three definitions of cardiomegaly. With a CTR threshold of 0.57, cardiomegaly can be identified with a very high specificity. This may be useful if PMCT is used by forensic pathologists as a screening tool for medico-legal autopsies.

Intravascular gas distribution in the upper abdomen of non-traumatic in-hospital death cases on postmortem computed tomography

Objectives To investigate the occurrence of intravascular gas in the liver, kidneys, spleen, and pancreas by postmortem computed tomography (PMCT) in cases of non-traumatic in-hospital deaths and elucidate the relationship between the PMCT data and clinical information or autopsy results. Methods The study included 45 cadavers of patients who died while receiving treatment in our academic tertiary-care hospital between April and December 2009. All subjects underwent PMCT and conventional autopsy. The appearance of postmortem gas in the liver, kidney, spleen, and pancreas was assessed using PMCT and scored using a subjective scale (liver, L0–L3; kidney, K0–K2; spleen, S0–S1; and pancreas, P0–P1), and the distribution of gases in the vessels of the liver (arteries, veins, and portal veins) was analyzed. The relationship between the gas score and time elapsed since death, cardiopulmonary resuscitation (CPR), administration of antibiotics, a history of bacteremia, or cause of death was assessed statistically. Results Positive correlations were found between administration of CPR and liver and kidney gas scores ( P = 0.008 and 0.002, respectively), but not with spleen and pancreas gas ( P = 0.291 and 0.535, respectively). No significant relationship between distribution of gas in the vessels of the liver and CPR was found. No other significant correlations between gas and any of the other parameters described above were found. While significant correlations were detected in no-CPR cases between liver gas, kidney gas, spleen gas, and pancreas gas ( P < 0.001 for all six combinations), no correlation between these parameters was detected in the CPR cases. Conclusions The present study was the first statistical analysis of intravascular gas in the liver, kidneys, spleen, and pancreas by using PMCT in non-traumatic in-hospital death cases. The results showed that PMCT in the presence and absence of CPR reveals differences in intraorgan gas distribution. In addition, the detection of intraorgan gas on PMCT cannot be used to predict time elapsed since death, and it is not affected by the administration of antibiotics, a history of bacteremia, and cause of death. Awareness of these postmortem changes is important for the accurate interpretation of PMCT results.

Post-mortem radiological CT identification based on classical ante-mortem X-ray examinations

Radiological identification is important in forensic medicine. Identification using comparison of individualising structures with ante- and post-mortem conventional radiographs has been known for a long time. New radiological procedures such as computed tomography (CT) and magnetic resonance imaging (MRI) are being increasingly used for identification. In this paper, a new comparative approach using various radiological methods is described and its application demonstrated. This new approach is the comparison of ante-mortem conventional radiographs with projected images calculated from post-mortem CT data. The identification procedure will be illustrated with reference to the frontal sinus and the pelvis.

Extended CT Scale Overcomes Restoration Caused Streak Artifacts for Dental Identification in CT - 3D Color Encoded Automatic Discrimination of Dental Restorations

Besides DNA, dental radiographs play a major role in the identification of victims in mass casualties or in corpses with major postmortem alterations. Computed tomography (CT) is increasingly applied in forensic investigations and is used to scan the dentition of deceased persons within minutes. We investigated different restoration materials concerning their radiopacity in CT for dental identification purposes. Extracted teeth with different filling materials (composite, amalgam, ceramic, temporary fillings) were CT scanned. Radiopacities of the filling materials were analyzed in extended CT scale images. Radiopacity values ranged from 6000-8500HU (temporary fillings), 4500-17000HU (composite fillings) and >30710HU (Amalgam and Gold). The values were used to define presets for a 3D colored volume rendering software. The effects of filling material caused streak artifacts could be distinctively reduced for the assessment of the dental status and a postprocessing algorithm was introduced that allows for 3D color encoded visualization and discrimination of different dental restorations based on postmortem CT data.