Analysis of postmortem changes in internal organs and gases using computed tomography data

Postmortem computed tomography (PMCT) is a useful method to identify various causes of death and measure the volume of internal organs and gases. The purpose of this study was to investigate postmortem changes as measured by PMCT, and the relationship between the volume of organs and gases and postmortem interval (PMI).Forty-six cadavers (22 men, 24 women) were examined by CT before autopsy. The volumes of the lungs, intrahepatic gas, and intrarectal gas were measured by CT using a workstation. A stepwise regression analysis was used to establish a predictive equation to ascertain the measured volume using factors including sex, age, height, body mass index (BMI), body surface area (BSA), and PMI. For estimation of PMI, stepwise regression analysis was used.In the equations for each measured volume, height, diaphragmatic height, and BSA were adopted for the left lung; height and diaphragmatic height were adopted for the right lung; PMI was adopted for intrahepatic gas; and sex and PMI were adopted for intrarectal gas. In the PMI equations, left lung volume, intrahepatic gas, and intrarectal gas were adopted together with sex, weight, and BMI.Values of intrahepatic gas decreased with postmortem changes, while intrarectal gas increased. This may be useful in investigation of postmortem changes. It will be necessary to include other parts of the intestine and to analyze volume changes in gases from these parts after death.     

Deciduous teeth development in fetuses using postmortem computed tomography image analysis

Fetal age is estimated widely by body length and weight and skeletal or dental development and maturation. Regarding dental development, dental development charts reported by Schour and Massler and Ubelaker are well known. We tried to calculate the calcification rate of the deciduous teeth, mandibular cortical bone, and clavicle in fetuses utilizing postmortem computed tomography (CT) image analysis. The CT values within the circumferential area of the region of interest were automatically calculated using a software, and the calcification rate was calculated by performing single regression analysis. Our results showed that deciduous tooth calcification could be detected in over 19-week-old fetuses using CT images. The calcification of bones (mandibular cortical bone and clavicle) started earlier than the calcification of deciduous teeth. However, the calcification rate of the bones was slower compared to that of the deciduous teeth. The calcification rate of the deciduous teeth in fetuses using CT value may be effective to estimate fetal age and evaluate deciduous teeth development, suggesting that our established method is effective for age estimation in forensic dentistry.     

New identification possibilities with postmortem multislice computed tomography

Historically, radiographical identification has been done by comparing conventional antemortem and postmortem X-ray images. The advent of new technologies such as multislice computed tomography (MSCT) is making traditional antemortem examination increasingly less frequent. The authors present the results of MSCT study of 35 corpses, which demonstrated features potentially useful for identification purposes in ten cases. These features, which relate to abnormalities of postcranial bone as well as of the internal organs, are presented. Attempts were made to find any antemortem X-rays or MSCTs on the cases described to compare the two antemortem and postmortem images. Although antemortem imaging was recovered for only two cases (one case with a skeletal abnormality and one case with a visceral abnormality), it permitted for both cases the comparison of antemortem and postmortem MSCTs. Presented at the XXth Congress of International Academy of Legal Medicine, Budapest, Hungary, August 2006.     

Use of postmortem computed tomography angiography to detect vascular injuries accompanying skull base fracture

A 58-year-old woman who had presented for upper gastrointestinal barium examination accidently slipped from the movable bed, and her head became compressed between the end of the bed and the side wall. She suffered massive bleeding from her nose and ear followed by cardiac arrest, and subsequent attempts at cardiopulmonary resuscitation failed. A medicolegal autopsy was performed to reveal the cause of death, as part of the investigation of the accident. During the autopsy, postmortem cerebral CT angiography was carried out by injection of 5% gelatin-barium emulsion as a radiopaque contrast medium into the bilateral common carotid arteries, demonstrating transudation of the contrast medium into the right acoustic meatus and the sphenoidal sinus cavity. Considering that the body appeared anemic and that PMCTA suggested vascular injuries, the cause of death was definitively determined to be hemorrhagic shock due to injuries to the right internal carotid artery, accompanied by skull base fracture. Postmortem CT angiography played an important role in confirming that the vascular injuries had been responsible for the bleeding, as the lesions could not be fully confirmed by native CT or macroscopic examination.     

Objective evaluation of chest findings in infants by postmortem computed tomography

PurposeThe purpose of this study was to review the findings of computed tomography (CT) performed early postmortem on infants and to clarify the postmortem CT lung findings that occur in the absence of abnormal histopathological findings.Materials and methodsFrom July 2016 to March 2022, 72 infants were autopsied with postmortem CT (41 boys 31 girls, aged 0–36 (mean 8.2) months). Autopsy and postmortem CT lung findings were compared with the causes of death identified by the autopsies, namely sudden infant death syndrome (n = 37), acute circulatory system disease (18), drowning (7), asphyxia (5), and dehydration/undernutrition (5).ResultsThe %aerated lung volume (−700 HU or less) ranged from 0 % to 33 % (mean 1.5 %, median 0 %), being <1 % in 61 cases (84.7 %) and >3 % in 3/5 (60 %) of the dehydration/undernutrition group. The dehydration/undernutrition group showed significant preservation of lung field air content compared with the other causes of death groups (p < 0.05). Receiver characteristic curve analysis showed a cut off value of 0.8 % and area under the curve of 0.88806. The drowning group had significantly greater pleural cavity fluid retention than the other causes of death groups (p < 0.05). No correlation was found between postmortem interval and pleural cavity fluid retention. However, resuscitation time and pleural cavity fluid retention were correlated.ConclusionEvaluation of CT values on postmortem lung fields of infants usually reveals a marked decrease in air content. When air content exceeds 0.8% on infant postmortem CT, dehydration/undernutrition should be considered in the differential diagnosis.     

Spinal hyperostosis as an important sign indicating spine injuries on postmortem computed tomography

Although spine injuries are not always detectable on postmortem computed tomography (PMCT), spinal hyperostosis, an important risk factor for spine injury, is relatively easily detectable on PMCT. We therefore examined the utility of the detection of spinal hyperostosis on PMCT as an indicator of spine injury. Full-body PMCT images of 88 autopsy cases with a bruise on the face or forehead but no identifiable skull fracture were reviewed prior to autopsy for the identification and classification of spinal hyperostosis. Spine injuries were observed in 56.0% of cases with spinal hyperostosis and 1.6% of cases without spinal hyperostosis. Among the cases with spinal hyperostosis, spine injuries were observed in 66.7% of cases at stage 2 or 3 and in 88.9% of cases at stage 3. Spine injuries were diagnosed on PMCT in 33.3% of cases prior to autopsy. A significant association was found between spinal hyperostosis and presence of spine injury that cannot be detected on PMCT, indicating that the identification of spinal hyperostosis on PMCT may assist in detecting spine injuries. This finding suggests that investigation of the presence of spine injury based on the identification of spinal hyperostosis on PMCT may assist in determining the correct cause of death by autopsy.     

Use of postmortem computed tomography to reveal an intraoral gunshot injuries in a charred body

A 53-year-old man was found dead after a fire at his residence had been extinguished. Although a pistol was recovered beside the body, external examination was unable to indicate any gunshot wound because of severe charring of the body. Postmortem computed tomography (CT) scan performed prior to autopsy suggested an entrance gunshot wound in the posterior pharynx with loss of soft tissue and an internal bullet path through the right anterior and posterior parts of the occipital bone. Autopsy revealed an entrance gunshot wound with hemorrhage in the soft tissue of the posterior pharynx, massive contusion of the right occipital lobe, and subarachnoid hemorrhage in the right temporal lobe, both occipital lobes and the superior surface of the left cerebellar hemisphere, thus being consistent with the findings of postmortem CT. A carboxyhemoglobin concentration of 5% in blood from the cadaver was consistent with the lack of soot deposition from the larynx to the bronchus. These observations confirmed that death had been caused by an intraoral gunshot resulting in severe brain damage, before the body had been burned.     

Time-related change evaluation of the cerebrospinal fluid using postmortem CT

PurposeWe retrospectively evaluated the cerebro-spinal fluid (CSF) CT density at the lateral ventricle to compare the postmortem intervals in cadavers.Materials and methodsThe number of cadavers enrolled in this study was 189 (male 120, female 69). According to the estimated postmortem time, the cadavers were divided into 13 groups (postmortem day 0.5, 1, 1.5, 2, 2.5, 3, 4, 5, 7, 10, 14, 21, 30), and were also re-grouped into 3 groups according to the postmortem time-width: group A (postmortem day 0.5–2.5), group B (day 3–7), and group C (day 10–30). Comparisons between the CSF density and estimated postmortem time were also analyzed.ResultsThe CSF density was around 20 HU up to day 2.5, and it increased gradually after day 3. Day 3 and 4 presented higher CSF density than day 1 and 1.5 (p < 0.05). Day 7 presented higher CSF density than day 3 (p < 0.05).According to the postmortem time-width, the CSF density increased with postmortem time (p < 0.05).The simple linear regression equations presented negative correlation between CSF density and estimated postmortem time, and R² was 0.119.ConclusionThe CSF density increased, but not linearly, according to the postmortem time, and the 3rd postmortem day was the earliest time allowing the difference to be detected. The CSF density needs further evaluation to enable estimation of the postmortem time.     

Advances of dual source, dual-energy imaging in postmortem CT

This paper focuses on the use of multi-detector row dual-energy computed tomography (DECT) in the evaluation of postmortal examinations. The use of dual energy moves postmortem CT to an entirely new dimension of diagnostic sensitivity where contrast in the image is not merely limited to X-ray attenuation differences, but may include elements of functional and tissue characterization. This additional information may be used to improve the benefit postmortem imaging can provide to supplement and simplify the conventional autopsy.     

Use of postmortem coronary computed tomography angiography with water-insoluble contrast medium to detect stenosis of the left anterior descending artery in a case of sudden death

A 40-year-old man was found dead on a sidewalk in an expressway parking area one hour after he had entered the area on a motorcycle. A medicolegal autopsy was performed to reveal the cause of this sudden and unexpected death. Postmortem coronary CT angiography after introduction of 5% gelatin–barium emulsion as a radiopaque contrast medium into the heart demonstrated a significant arterial luminal filling defect in the left anterior descending (LAD) coronary artery. Macroscopic and microscopic examinations revealed that a thrombus had become deposited on ruptured plaque within the LAD artery, and that a small amount of the contrast medium was present between the thrombus and the vessel endothelium. These histological findings were consistent with incomplete occlusion of the LAD artery in the 3D reconstructed image. The cause of death in this case was definitively determined to be ischemic heart disease. Postmortem angiography played a role in screening of a vascular lesion that was subsequently verified by histology to have been responsible for sudden and unexpected death.     

Milk of calcium pericardial effusion confirmed with postmortem computed tomography and autopsy findings: A case report

We present the postmortem computed tomography and autopsy findings of a 60-year-old man who developed milk of calcium pericardial effusion and died of constrictive epicarditis. He experienced out-of-hospital cardiopulmonary arrest, and spontaneous circulation returned at the hospital. However, 7 h after recovery, the patient died. He had a swollen neck, had been experiencing coughing from 4 to 5 days earlier, and had no significant medical or surgical history. On computed tomography (CT), highly dense pericardial fluid (CT value: 130–150 Hounsfield units) and multiple calcifications along the epicardium and pericardium were visualized. The epicardium and pericardium were thick, hard, rough, and widely calcified with mild adhesions on autopsy. The pericardial cavity contained a pale, reddish brown, turbid, and highly viscous liquid. Bacteriological tests of pericardial fluid cultures revealed the presence of group G β-hemolytic streptococci. Hence, we diagnosed the patient’s cause of death as heart failure due to constrictive epicarditis. We believe that this case of milk of calcium pericardial effusion is the first case confirmed with postmortem CT and autopsy findings.     

64层螺旋CT在道路交通事故尸体检验中的初步应用

目的 探讨64层螺旋CT在道路交通事故全身尸体检验中的应用价值.方法 根据事故现场监控录像、现场勘查照片等获得本例行人道路交通事故的发生过程.由专业的法医于事故当天对遇难者尸体进行尸表检验,得出尸体检验报告.采用64层螺旋CT对遇难者尸体进行全身扫描,并在后处理工作站对CT断面图像进行多平面重建和三维重建.将CT图像所见与尸体检验报告进行比较.结果 尸表检验发现遇难者全身多处软组织损伤、蛛网膜下腔出血、血胸、多发肋骨骨折、鼻骨骨折.认为遇难者系交通事故致颅脑损伤、胸腔脏器损伤死亡.64层螺旋CT扫描结果显示遇难者颅脑、胸部、腹部、骨盆及脊柱多器官、多脏器发生严重的损伤.结论 64层螺旋CT可获得比尸表检验更多、更重要的组织器官和脏器损伤信息,两者联合应用,可为道路交通事故伤情鉴定提供更充分、可靠的依据.     

Blunt traumatic rupture of the pericardium with cardiac herniation: two cases diagnosed using computed tomography

Traumatic ruptures of the pericardium with cardiac herniation are infrequent, and their radiological pattern little familiar, so that they are often missed preoperatively. Few reports have emphasised the use of a CT scan as a tool for diagnosis and CT scan signs have not been well documented. We report on two cases of traumatic herniation of the heart for which a CT scan brought a major contribution for diagnosis. We describe the presence of an empty pericardial sac on CT slices which allowed us to diagnose the cardiac herniation. These observations demonstrate that CT scans can contribute to the diagnosis of pericardial rupture with cardiac herniation.     

Pulmonary postmortem computed tomography of bacterial pneumonia and pulmonary edema in patients following non-traumatic in-hospital death

In this study, we compared the postmortem computed tomography (PMCT) findings among nonpathological lungs, lungs with bacterial pneumonia, and lungs with pulmonary edema in patients following non-traumatic in-hospital death. We studied 104 consecutive adult patients (208 lungs) who died in our tertiary care hospital and underwent PMCT and pathological autopsy (both within 2.5 days after death), and were pathologically diagnosed with nonpathological lungs, bacterial pneumonia, and pulmonary edema. Thirteen pulmonary features were assessed on the CT scans. We also examined the association between the time elapsed since death and the pulmonary findings. We observed increased lung opacities with horizontal plane formation, diffuse opacities, diffuse bronchovascular bundle thickening, symmetric opacities to the contralateral lung, and decreased segmental opacities with time elapsed since death (Cochran–Armitage test for trend). Multiple logistic regression revealed that the presence of opacities without horizontal plane formation or centrilobular opacities, and the absence of diffuse bronchovascular bundle thickening were associated with histopathological pneumonia, whereas the presence of opacities with horizontal plane formation, diffuse opacities, and interlobular septal thickening were associated with histopathological pulmonary edema. In conclusion, specific pulmonary PMCT findings increased with time elapsed since death, and some lung findings may facilitate the diagnosis of bacterial pneumonia and pulmonary edema.     

The usefulness of postmortem computed tomography angiography for subdural hematoma caused by rupture of the cortical artery: A report of two autopsy cases and a literature review

Acute subdural hematoma (SDH) occurs following severe head trauma with brain contusion or rupture of bridging veins. Conversely, SDH caused by rupture of a cortical artery without trauma or with minor trauma is also possible. Although over 180 cases of the latter SDH have been reported, they were predominantly diagnosed only during surgery, and therefore, no adequate histological evaluation has been performed. Therefore, essential etiology of this SDH type has remained unclear. In addition, the scarcity of autopsy cases may be attributed to arterial rupture being missed if the microscopic findings are too minimal to detect during autopsy. Here, we describe two autopsy cases of SDH of cortical artery origin. Extravasation on postmortem computed tomography angiography and arterial leakage on macroscopic observation during autopsy facilitated detection of the ruptured artery and allowed detailed histological evaluation of the ruptured artery and adjacent dura mater. The etiology of arterial rupture is briefly described on the basis of histopathological findings in this study and the available literature.     

Freezing effect on brain density in postmortem CT

Two 60-year-old males were found at their homes whose bodies had deteriorated due to putrefaction. To prevent worm invasion and minimize deterioration, dry ice was used prior to the autopsy investigation. Prior to autopsy, postmortem CT demonstrated a decreased density in brain parenchyma at the dry-iced side, and autopsy revealed deteriorated brain parenchyma with frozen effect (presented like sherbet). Moreover, the deteriorated cerebral parenchyma maintained their structure and they were evaluated by cutting. When lower CT density presents in postmortem CT, the freezing effect may need to be considered and the physician should evaluate the cadaver’s postmortem condition to prevent misdiagnoses.     

A case of fatal drug intoxication showing a high-density duodenal content by postmortem computed tomography

A 22-year-old woman was found dead in her bed, and subsequent postmortem examination was performed using ordinary methods such as external examination, Triage?, and computed tomography (CT) scan which demonstrated a high-density content of the duodenum. Autopsy and quantitative analysis of drugs present in the GI tract showed that high amounts of radiopaque psychotic agents such as fluvoxamine maleate, carbamazepine, and zolpidem tartrate had been responsible for the high-density profile of the duodenum. Postmortem quantitative analysis of drugs in the blood suggested that death had been caused by fatal intoxication with fluvoxamine maleate. Thus, postmortem CT could offer an opportunity to suspect drug intoxication due to radiopaque psychotic agents such as chloral hydrate, phenothiazine, bromovaleryl urea, fluvoxamine maleate, and probably zolpidem tartrate, although it is neither a specific nor a quantitative test for drugs. Therefore, postmortem CT happened to provide clues to investigation of drug intoxication in the present case.     

Estimation of postmortem time based on aorta narrowing in CT imaging

Computed tomography (CT) in forensic medicine is commonly used in determination of cause of death. Here, we show that the information provided by CT may also be of value for estimation of time after death. The relationship between abdominal aorta narrowing just below the diaphragm and time after death was examined in 140 cases. Aorta narrowing was defined using a flatness ratio, which was calculated by dividing the shorter axis of the aorta by the longer axis. Time after death was classified into 6 time periods. The flatness ratio gradually and significantly decreased with increased postmortem time, showing increased aorta narrowing with increased time after death. A further examination of aorta narrowing in 15 autopsy cases in which CT images were taken at two postmortem times gave similar findings. The results of the study suggest that aorta narrowing in postmortem CT imaging may be used to estimate time after death.     

Study of postmortem blood circulation

Summary The objective of this work was to study the postmortem redistribution of blood volumes and its influence of the distribution of substances of different molecular weight (194.2 and 150,000 Da). Lipiodol Ultrafluide, Omnitrast, or a radioisotopic mixture of aminohippuric acid and human IgG were injected into the left ventricle of a total of 20 rabbits divided into three groups. Our results demonstrate the importance of related factors, including left ventricular postmortem contraction, the arterial vascular bed, diffusion processes connected to the physicochemical characteristics of the substances, and the anatomical distribution of the vessels. Postmortem diffusion of aminohippuric acid to the urine was observed.     

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.