Postmortem Computed Tomography Images Research Articles

Public awareness of the use of clinical CT machines for postmortems

Abstract Background Japan has one-third of the world's CT machines and the highest number of CT devices per million population. The lack of medical examiners to meet the needs of Japanese police authorities has therefore led to requests that CT scanners be used for both clinical and postmortem examination. However, hospitals believe that patients might feel uncomfortable with this dual use, so they usually advocate performing postmortem cases at night and not informing patients of the dual use of CT scanners. In this study, we investigated people's thoughts about the dual use of CT scanners. Methods In this internet-based questionnaire study, we wanted to understand public opinion about postmortem CT imaging. Specifically, we sought the opinions of the general public about the Japanese death investigation system and the use of CT machines for both the living and the dead. Results More than 70% of respondents wanted postmortem examinations to identify the cause of death, but only 34% were aware that CT was used for this purpose. Moreover, only 13% knew that postmortem CTs were performed at general hospitals using CT machines that are also used for patients, and 51.6% thought that hospitals should inform patients that CT machines are also used for postmortem examinations. Conclusions There are no rules for the use of the clinical CT machines for postmortem examination in Japan. However, we identified that half of our respondents wanted to be informed that hospitals use CT scanners to examine both the living and the dead.

Frequency and influencing factors of cardiopulmonary resuscitation-related injuries during implementation of the American Heart Association 2010 Guidelines: a retrospective study based on autopsy and postmortem computed tomography

To determine the frequency of cardiopulmonary resuscitation (CPR)-related injuries and factors involved in their occurrence, data based on forensic autopsy and postmortem computed tomography (PMCT) during implementation of the 2010 American Heart Association Guidelines for CPR were studied. We retrospectively evaluated data on adult patients with non-traumatic deaths who had undergone manual CPR and autopsy from January 2012 to December 2014. CPR-related injuries were analyzed on autopsy records and PMCT images and compared with results of previous studies. In total, 180 consecutive cases were analyzed. Rib fractures and sternal fractures were most frequent (overall frequency, 66.1 and 52.8%, respectively), followed by heart injuries (12.8%) and abdominal visceral injuries (2.2%). Urgently life-threatening injuries were rare (2.8%). Older age was an independent risk factor for rib fracture [adjusted odds ratio (AOR), 1.06; 95% confidence interval (CI), 1.04-1.08; p<0.001], ≥3 rib fractures (AOR, 1.06; 95% CI, 1.02-1.09; p=0.002), and sternal fracture (AOR, 1.03; 95% CI, 1.01-1.05; p<0.001). Female sex was significantly associated with sternal fracture (AOR, 2.08; 95% CI, 1.02-4.25; p=0.04). Chest compression only by laypersons was inversely associated with rib and sternal fractures. Body mass index and in-hospital cardiac arrest were not significantly associated with any complications. The frequency of thoracic skeletal injuries was similar to that in recent autopsy-based studies. Implementation of the 2010 Guidelines had little impact on the frequency of CPR-related thoracic skeletal injuries or urgently life-threatening complications. Older age was the only independent factor related to thoracic skeletal injuries.

Post-mortem CT imaging of the lungs: pathological versus non-pathological findings.

Nowadays, the modern computed tomography techniques are more and more applied in forensic investigations. The detection of abnormalities in post-mortem computed tomography (PMCT) imaging of the lungs is very common. As in clinical imaging, also in post-mortem imaging the right interpretation of alterations has an extreme importance for the assessment of correct conclusions. This is even crucial when the radiologist who approaches the PMCT images is not routinely involved in forensic cases. The aim of this article is to provide radiologists who approach PMCT imaging cases with some indications for a proper and correct interpretation of pulmonary findings, to avoid misleading forensic conclusions. Particularly, the following issues will be addressed: PMCT imaging of post-mortem changes of the lungs; PMCT imaging of pathological lungs [(a) in thoracic trauma cases, (b) in cases without thoracic trauma]. Finally, the possible pitfalls in interpretation of PMCT imaging of the lungs will be also discussed.

Fast three-dimensional whole-body post-mortem magnetic resonance angiography

Abstract Purpose The goal of this study was to perform whole-body post-mortem magnetic resonance (PMMR) angiography with imaging quality comparable to that of post-mortem computed tomography (PMCT) angiography. Methods After contrast medium injection into the arterial and venous vascular system of seven human corpses PMMR was performed using a fast three-dimensional T1 weighted spoiled gradient-echo sequence, followed by PMCT imaging. The contrast medium volumes inside the descending aorta and inside the inferior vena cava were measured both on PMMR and on PMCT images by means of image segmentation. Visualization quality of arterial and venous vessels as a function of contrast filling was scored according to a four-point scale and compared using the paired Wilcoxon signed rank test. Results The contrast medium volume in the descending aorta decreased 12% on average from PMMR to PMCT angiography, while the contrast medium volume in the inferior vena cava increased by 11% on average. A total of 410 vessels were analyzed. Scores for all vessels were statistically significantly smaller for the PMMR angiography when compared to PMCT angiography (p = 0.01). No statistically significant differences were found for the subgroups of large vessels (p = 0.21), for the head and neck (p = 0.16) or the abdomen (p = 0.83) as well as for the thorax when the coronary arteries were left out (p = 0.23). Conclusions This study demonstrates that immediate image acquisition after contrast injection and rapid 3D whole-body image acquisition offers good image quality in PMMR angiography with a vascular contrast comparable to PMCT angiography.

Post-mortem computed tomography findings of the frozen brain

Abstract Post-mortem computed tomography (CT) is a valuable tool in forensic medicine. Determination of cause of death may require examination of a corpse found in a frozen state. However, most radiologists are unfamiliar with the post-mortem appearance of frozen organs on CT. Here we present two cases that included CT study of the frozen brain. Both bodies were naturally frozen, and autopsies showed that the cause of death was hypothermia in both instances. On post-mortem CT images, the frozen brains exhibited hypodense areas resembling infarctions, but these were not in regions dominated by blood vessels. Residual open sulci were evident, suggesting that oedema was absent. These two features are helpful when diagnosing a frozen brain on CT images.

Subtentorial Meningioma Misdiagnosed as Cerebral Hemorrhage in Postmortem Computed Tomography Imaging

This report presents a case of a 52-year-old man who had a traffic accident and died later. External examination could not determine the cause of death. Approximately 3 weeks later, an autopsy was performed. Postmortem computed tomography was performed before the autopsy. Postmortem imaging was interpreted to show hemorrhage beneath the tentorium, and the C5 to C6 (the fifth and sixth cervical vertebra) disc space was widened. During the autopsy, a cervical spinal cord injury was confirmed. However, a meningioma was found under the tentorium instead of a hemorrhage. There are a number of reasons that include postmortem changes that affected the virtopsy diagnosis, which still needs development.

Differentiation of hemopericardium due to ruptured myocardial infarction or aortic dissection on unenhanced postmortem computed tomography.

The aim of the study was to evaluate unenhanced postmortem computed tomography (PMCT) in cases of non-traumatic hemopericardium by establishing the sensitivity, specificity and accuracy of diagnostic criteria for the differentiation between aortic dissection and myocardial wall rupture due to infarction. Twenty six cases were identified as suitable for evaluation, of which ruptured aortic dissection could be identified as the underlying cause of hemopericardium in 50% of the cases, and myocardial wall rupture also in 50% of the cases. All cases underwent a PMCT and 24 of the cases also underwent one or more additional examinations: a subsequent autopsy, or a postmortem magnetic resonance (PMMR), or a PMCT angiography (PMCTA), or combinations of the above. Two radiologists evaluated the PMCT images and classified each case as "aortic dissection", "myocardial wall rupture" or "undetermined". Quantification of the pericardial blood was carried out using segmentation techniques. 17 of 26 cases were correctly identified, either as aortic dissections or myocardial ruptures, by both readers. 7 of 13 myocardial wall ruptures were identified by both readers, whereas both readers identified correctly 10 of 13 aortic dissection cases. Taking into account the responses of both readers, specificity was 100% for both causes of hemopericardium and sensitivity as well as accuracy was higher for aortic dissections than myocardial wall ruptures (72.7% and 87.5% vs 53.8% and 75% respectively). Pericardial blood volumes were constantly higher in the aortic dissection group, but a statistical significance of these differences could not be proven, since the small count of cases did not allow for statistical tests. This study showed that diagnostic criteria for the differentiation between ruptured aortic dissection and myocardial wall rupture due to infarction are highly specific and accurate.

Usefulness of 2D fusion of postmortem CT and antemortem chest radiography studies for human identification.

To determine the feasibility of human identification through the two-dimensional (2D) fusion of postmortem computed tomography (PMCT) and antemortem chest radiography. The study population consisted of 15 subjects who had undergone chest radiography studies more than 12months before death. Fused images in which a chest radiograph was fused with a PMCT image were obtained for those subjects using a workstation, and the minimum distance gaps between corresponding anatomical landmarks (located at soft tissue and bone sites) in the images obtained with the two modalities were calculated. For each fused image, the mean of all these minimum distance gaps was recorded as the mean distance gap (MDG). For each subject, the MDG obtained for the same-subject fused image (i.e., where both of the images that were fused derived from that subject) was compared with the MDGs for different-subject fused images (i.e., where only one of the images that were fused derived from that subject; the other image derived from a different subject) in order to determine whether same-subject fused images can be reliably distinguished from different-subject fused images. The MDGs of the same-subject fused images were found to be significantly smaller than the MDGs of the different-subject fused images (p<0.01). When bone landmarks were used, the same-subject fused image was found to be the fused image with the lowest MDG for 33.3% of the subjects, the fused image with the lowest or second-lowest MDG for 73.3% of the subjects, and the fused image with the lowest, second-lowest, or third-lowest MDG for 86.7% of the subjects. The application of bone landmarks rather than soft-tissue landmarks made it significantly more likely that, for each subject, the same-subject fused image would have the lowest MDG (or one of the lowest MDGs) of all the fused images compared (p<0.05). The 2D fusion of antemortem chest radiography and postmortem CT images may assist in human identification.

Estimating Age at Death Based on Costal Cartilage Calcification.

Age estimation is a crucial part of forensic investigations. Because different parts of the body are often found at crime scenes, it is important to explore the regions that can be used for age estimation. Previous studies have used simple X-ray to analyze changes in costal cartilage calcification as a measure of age. Here, we tested whether age could be better estimated using measurements of costal cartilage calcification on postmortem CT images. In this study, male and female decedents (n = 10 each) from autopsy cases were grouped into 10-year incremental age groups (20-29 y; 30-39 y; up to 89 y). We found that the mean Hounsfield unit (CT number) and percentage calcification (the ratio of the ossified area to the whole area) increased with age for both sexes. However, there were marked individual differences within many of the groups, and this led to a statistically significant difference (P < 0.05) only between the 20-29 y group and the older age groups. To improve the ability to correctly assign cases to age groups, we introduced and reanalyzed the data using Bayesian statistics. This improved the classifications rates, with 40% of males and 35% of females correctly assigned into their age groups. Broadening the age range could further improve the number of matches. Thus, combining Bayesian statistics with CT imaging can be used to estimate age at death from costal cartilage calcification, and could be used as an adjunct in forensic investigations.

Postmortem Computed Tomographic Analysis of Death Caused by Oral Drug Intoxication

Traditional autopsy has changed little in the past century. In Japan, the rate of forensic autopsy in cases of unusual death is very low. Therefore, multi-slice computed tomography (CT) has been used to obtain imaging data instead of or in addition to autopsy in suspicious forensic cases. In our institute, postmortem multi-slice CT has been performed since 2009, and by 2014 there were over 1,000 cases. Our extensive experience with postmortem CT shows that in many cases of death by drug overdose, stomach contents exhibit high X-ray absorption. This article reviews the relationship between CT findings of stomach contents and toxicological analysis results in 23 cases of death by drug overdose. All cases (12 females and 11 males, aged 44 ± 11 years) known to have orally ingested drugs were included in this study. We assessed the slices of all stomach areas on consecutive axial CT images. Twenty cases (87%) showed high X-ray absorption in the stomach, while the other three did not demonstrate radio-dense stomach contents even though drug analysis detected lethal concentrations of drugs in the blood. In conclusion, drugs were frequently, but not always, visualized as contents with high X-ray absorption in the stomach. Postmortem gastric CT images can provide useful information in cases of oral drug intoxication if there are empty drug packages or a suicide note at the death scene. However, precise determination of the cause of death requires full autopsy in cases where there is no indication of suicide at the death scene.

Age estimation by ossification of thyroid cartilage of Japanese males using Bayesian analysis of postmortem CT images.

Many studies have reported that the degree of thyroid cartilage ossification correlates with age. However, its use in forensics has been limited by individual variation, tissue fragility, and observer subjectivity. We examined a new method for age estimation from the degree of ossification of thyroid cartilage using postmortem computed tomography (CT) and Bayesian analysis. The scoring of CT density values, ossification rate, and morphological changes was performed in 131 Japanese males (20-80years old), and an age estimation table was created and verified in 39 other Japanese males. We tried two types of prior probability; one was males undergoing postmortem CT imaging at our institute, and the other was the age composition of the male population in Japan. The differences in percentage in each age group were observed, especially in the ninth decade, but they were not large enough to change the result. Two decedents in their 30s and 80s could not be assigned an age group. Likelihood might have had more significant influence than prior probability. Bayesian approach and new scoring system of thyroid cartilage ossification might be useful as an age estimation method. Although the low posterior probability in decedents the age ≧70 remains a problem, the advantage of Bayesian estimation that it can sequentially update the age estimation table by factoring in exceptional data can solve this problem. In this study, accuracy of age estimation did not dramatically increase, however, Bayesian statistics might become a useful technique for examining any tissue samples subject to age-related calcification.

Post-mortem CT evaluation of atlanto-occipital dissociation

Atlanto-occipital dissociation injury is an important injury in forensic pathology practice. Radiological diagnosis of atlanto-occipital dissociation clinically is assessed by direct measurement of occipito-vertebral skeletal relationships. Different measurements may be used to diagnose atlanto-occipital dissociation, including the basion-dens interval (BDI) and basion-axial interval (BAI). It is not known whether the normal ante-mortem measurements of BDI and BAI described in the literature are applicable to post-mortem CT images of the occipito-cervical junction (OCJ) or whether these measurements could be affected by early post-mortem changes. This study aims to compare post-mortem BDI and BAI measurements with ante-mortem values. Post-mortem CT scans of the cervical spines of 100 deceased adults were reviewed, and the BDI and BAI were measured. Different parameters were recorded in each case. The results from this study suggest that there are no effects of post-mortem changes on the measurement of BAI as relied upon clinically. There appear to be some effects of fully established rigor mortis on BDI measurement, shortening it. This may have consequences for the post mortem diagnosis of atlanto-occipital dissociation.

Assessment of head gunshot wounds by means of post-mortem computed tomography in exhumed anonymous cadaver

Autopsy of corpses with advanced post-mortem changes is the most challenging aspect of medico-legal activities. In many cases, owing to soft tissue decomposition, making a final diagnosis as to the mechanism and cause of death is very difficult, and sometimes impossible (Carcione P, Argo G, Pincone D, Zgo S, Scopelliti L, Sortino C, Procaccianti P. Role of MCT vitropsy in evaluation of burned bodies and its comparison with traditional autopsy. Poster No.: C-1156, ECR 2014, Scientific exhibit). In such cases, the diagnostic process can be supported by post-mortem CT imaging. Post-mortem multislice CT imaging used in the field of forensic medicine is widely reported to be a good method for visualizing injuries and natural pathologies; however, only a limited number of forensic departments use this method in everyday practice. This method enables accurate assessment of bony injuries (fracture type, degree of bone displacement); has the ability to detect radiopaque foreign bodies, most frequently fragments of bullets; and in some cases enables soft tissue delineation (Hardy K. CT autopsy. Radiology Today 2008; 9: 20. Available from: http://www.radiologytoday.net/archive/rt01282008p20.shtml). In cadavers with advanced post-mortem changes, it is extremely difficult to retrieve the whole bullet or its parts. Owing to decomposition and reduced cohesion of the tissues, standard autopsy preparation techniques are impossible to perform. Post-mortem changes may also cause displacement of the bullet within the body in the long term, as well as at the time of transport following exhumation (Maiese A, Gitto L, De Matteis A, Panebianco V, Bolino G. Post mortem computed tomography: useful or unnecessary in gunshot wounds deaths? Two case reports. Leg Med (Tokyo) 2014; 16: 357–63). It is therefore important to perform post-mortem CT imaging directly after extraction of corpses in a similar position to how the dead body was exhumed. Interpretation of the images requires cooperation of forensic medicine specialists and radiologists to correlate radiological findings with autopsy.

Postmortem gastromalacia

The aim of this case report is to describe the postmortem computed tomography (PMCT) and forensic autopsy investigation findings of a case of antemortem gastric perforation in a dog. A 13-year-old, spayed female, pit bull type dog with a recent history of limping, anorexia, and lethargy, was treated with unknown doses of an unknown corticosteroid, grapiprant (a veterinary nonsteroidal anti-inflammatory drug [NSAID]), and omeprazole, prior to euthanasia. PMCT was subsequently completed, followed by confirmatory forensic autopsy. On PMCT images, a full thickness gastric wall discontinuity with confluent luminal and extraluminal gas (pneumoperitoneum) was identified. In the absence of expected additional sites of postmortem intracavitary gas accumulation (pleural, peri-cardial, and intra-articular) the pneumoperitoneum was attributed primarily to antemortem gastric rupture, which precipitated patient decline and subsequent euthanasia. Forensic autopsy revealed gastric ulceration with perforation. Histological evaluation of the perforation site revealed suppurative inflammation and an early healing response. The combined findings of the PMCT and autopsy were compatible with antemortem gastric perforation attributable to the historical concurrent administration of a NSAID and corticosteroid. Given adequate radiologist knowledge and training, antemortem gastric perforation may be differentiated from postmortem gastromalacia with rupture.

Validation of post mortem dental CT for disaster victim identification

Abstract The objective of this study was to test the accuracy and inter-reader variability of comparative radiologic identification based on dental post mortem computed tomography (PMCT) and ante mortem (AM) dental radiographs. Five raters with varying degrees of expertize and experience independently compared 115 dental PMCT images to 114AM dental radiographs to identify matching pairs ( n =98), unmatched PMCT images ( n =17), and unmatched AM radiographs ( n =16). Levels of confidence (LOC) and number of concordant features (NOCF) of matched pairs were documented. Accuracy of matches/exclusions, interrater correlation coefficient and correlation between correct matches/exclusions, LOC and NOCF were calculated for all raters. Mean accuracy was 92% for matches and 80% for exclusions. Interrater correlation coefficient regarding LOC and NOCF were 0.623 and 0.907 respectively. LOC were correlated with NOCF of matched pairs but accuracy of matches/exclusions was neither correlated to LOC nor to NOCF. This study shows that visual comparison of PMCT images with AM dental radiographs is a reliable method for identification. Accuracy of identification using PMCT/AM dental radiographs was as high as in comparable studies using post mortem (PM) dental radiographs/AM dental radiographs. Raters with practical experience in forensic identification and experience with the imaging modality (in this case: dental PMCT) achieved higher accuracy than inexperienced raters. Match accuracy did not correlate with subjective confidence or number of concordant features. It is advised to work in teams rather than individually when dealing with real cases in forensic identification, to minimize subjective interpretation and avoid confirmation bias.

Ventilated post-mortem computed tomography – A historical review

Abstract In an attempt to improve the diagnostic quality of post-mortem computed tomography (PMCT) lung image interpretation, a series of authors have developed an approach that mimics deep inspiration and breath hold clinical thoracic CT imaging in the dead. Known as ventilated post-mortem computed tomography or VPMCT this technique has now been developed and applied to adult and paediatric PMCT imaging. This review, authored by the principal pioneers of this system, outlines the developmental stages of VPMCT, bringing the reader up to date with current knowledge and practice.

FEATURES OF COMPUTED TOMOGRAPHY AUTOPSY: THE PROBLEM OF INTERPRETATION OF SPECIFIC AND NONSPECIFIC ARTIFACTS

The literature review analyzes studies on postmortem CT as an alternative to the conventional autopsy in forensic examination of the bodies of an adults. The main objective of the review is to give a brief analysis of the characteristics of post-mortem CT imaging, which do not face the clinical radiologists in their practice. The analysis comes up with 72 literature sources. The basic Internet resources were used during preparation of the study: Scientific Electronic Library (elibrary), SciVerse (ScienceDirect), Scopus, PubMed, and Discover. The review includes articles which discuss both the advantages and limitations of CT in the posthumous forensic examination of the bodies of an adults, and especially post-mortem CT imaging the most common pathological processes and artefacts. Conclusions. Early and late postmortem changes, such as rigor, autolysis, putrefaction and others largely change the normal pattern in CT imaging clinical radiologists are used to. In particular, the interpretation of CT images of the corpse must consider common specific and non-specific artefacts which result from: agonal changes (alteration in anatomical appearance, decomposition); autolysis, putrefaction; regurgitation of gastro-intestinal contents, aspiration; lividity and hypostasis; postmortem blood clotting; resuscitation effects; postmortem handling/autopsy technique; insect activity; and many others. These artefacts are not pathological findings, and should always be taken into account when interpreting the postmortem CT images.

Radio-visualization of non-specific postmortem changes in the cardiovascular system

This paper presents a review of the literature concerning radio-visualization of non-specific postmortem changes in the cardiovascular system during computed tomography and magnetic resonance imaging. The peculiar radiological characteristics of postmortem blood clots and cadaveric hypostases in the internal organs are described. It is emphasized that postmortem CT and MRI can not replace the pathological anatomical studies and forensic medical autopsy. Roentgenologists engaged in the postmortem examination of the bodies must have relevant knowledge of pathological anatomy and forensic medicine (namely, they must be aware of the non-specific postmortem changes) to be able to adequately interpret the tomograms obtained and correctly establish the diagnosis. It is recommended that the postmortem CT and MRI images should be used as an additional material for the traditional autopsy, e.g. as a preliminary 'guide' preceding the postmortem examination.

An autopsy case of an elderly man with myelodysplastic syndromes in which postmortem computed tomography showed massive splenomegaly

Abstract Here we describe the findings of autopsy of an elderly man with several critical diseases, including myelodysplastic syndromes (MDS), who experienced sudden natural death in which postmortem computed tomography (PMCT) provided useful information in determining the cause of death. A man in his late 80s suffered a cardiopulmonary arrest at his home. Although previously diagnosed with MDS and chronic heart failure, he had not consulted a physician for several years. PMCT images showed massive splenomegaly and consolidation in the right lung, whereas signs suggestive of pulmonary edema were not evident in the left lung. Macroscopic autopsy findings included splenomegaly (1748 g) and dark red coloring of the right lung, but no significant heart enlargement (366 g). Microscopic findings included extensive hemorrhage in the alveolar space in the right lung, hypercellular bone marrow with monotonous cell proliferation, and infiltration of those cells in various organs. Immunohistochemical staining showed that the proliferating cells were strongly positive for myeloperoxidase. Based on review of the autopsy findings, we concluded that the underlying cause of death was acute myeloid leukemia. Review of this case suggests that PMCT may be useful in identifying the cause of death of elderly persons with several critical diseases who experience sudden natural death. Utilizing PMCT findings may allow for compilation of accurate mortality statistics regarding the elderly population, although physicians should consider the limitations of PMCT when deciding whether to perform autopsy.

Interpretation of intravascular gas on postmortem CT in children

Abstract Introduction The use of post-mortem computed tomography (PMCT) is increasing, but the significance of some findings, such as intravascular gas, remain uncertain. In order to correctly interpret the findings, we provide data on a series of cases in whom intravascular gas was noted on PMCT imaging, to assess whether it correlates with clinical features including type of death (traumatic), resuscitation and postmortem interval. Methods Children Results 46 children, mean age 2 years (range 0 days–15.5 years) were included in the study. 63% (29/46) children demonstrated IV gas postmortem. No relationship was demonstrated between IV gas at PMCT and increasing postmortem interval or traumatic death. IV gas was seen more commonly following resuscitation attempts including intra-osseous needle insertions, although this did not reach statistical significance. Conclusion IV gas is commonly identified on PMCT in children, and may be related to resuscitation rather than putrefaction or decomposition. A better understanding of IV gas on PMCT will help interpret these findings on future studies.