Postmortem Computed Tomography Images Research Articles

Multi-centre post-mortem study on the use of coronary inflammation in CCTA to improve the diagnosis of the coronary related cause of death with histopathology validation

Abstract Background/Introduction A limitation of post-mortem computed tomography (PMCT) is the diagnostic accuracy of coronary related death, which constitute majority of investigations. Measurements using coronary inflammation with fat attenuation index (FAI) Score, clinical risk factors and coronary plaque metrics from CCTA to predict fatal cardiac events (AI-Risk) in living patients has not been used in post-mortem setting. Purpose This study investigates two new techniques to aid the diagnosis of coronary related death in the post-mortem setting: (1) minimally invasive interventional technique to perform PMCT; (2) diagnostic accuracy of FAI-assisted PMCT with histopathology validation. Method Adults with sudden death of unknown cause <48 hours from death were included. Ultrasound guided femoral access to deliver guidewire to the aortic root (Figure 1A), followed by inflation of aortic occlusion balloon and injection of contrast for angiogram. A cardiac radiologist performed the coronary and FAI analysis (1B &C). Two experienced radiologists reported the cause of death without/with aid of FAI score results. The technique was introduced at a second PMCT centre. Results PMCT analysis of 37 participants (27 males, 10 females, age range 42-98) – 15 minimally invasive PMCT, and 22 PMCT from previous study showed FAI score (1D) and AI-Risk (1E) were significantly higher in participants who had coronary related death vs non-coronary related causes. In the receiver operating characteristic (ROC, 1F) analysis, thresholding at 42% for AI-Risk and 34 for Mean FAI score, was able to detect all 18 true positives, 2 false positives (1xpulmonary embolism, and 1xdual pathology of ruptured abdominal aneurysm with severe coronary artery disease; these cases showed high FAI score and AI-Risk), and all true negatives. Both radiologists identified 17/18 coronary related death. There were 5 cases of false positives for coronary related death in Radiologist 1 (3 years’ experience); 8 false positives in Radiologists 2 (10 years’ experience). In non-coronary related deaths, Radiologist 1 identified 14/19 true negative cases, and Radiologist 2 identified 11/19 true negative cases. In all the false positive and negative cases, the radiologists’ diagnostic confidence level was either possible, or unascertain. With the aid of FAI score results, all the true coronary related deaths were identified and no false negative case. This method was introduced at a second centre with 108 PMCTs analysed. There were 40 cases of non-coronary death, and 68 cases of coronary related death on PMCT (imaging diagnosis only). In the non-coronary group, FAI-score assisted results showed 100% concordance. In the coronary group, there was 10% dis-concordance (7/68). Conclusion Minimally invasive PMCT with FAI score-assisted diagnosis has the potential to increase the diagnostic confidence and accuracy of coronary-related cause of death.

The role of computed tomography in post-mortem examinations.

In the study, data from the literature regarding the use of computed tomography in post-mortem examinations (post-mortem computed tomography - PMCT) were analyzed. Literature data indicate that PMCT should be used as a complementary tool rather than an alternative to autopsy, detecting additional changes that may have been unnoticed due to anatomical location or the need to extend traditional autopsy techniques. The ability to save, create and reconstruct images is very helpful in creating documentation and final opinions. There is a need to develop standards for the evaluation of post-mortem computed tomography images, which will enable further development of virtual autopsy techniques in the field of forensic medicine, supported by artificial intelligence.

Evaluation of age estimation using alveolar bone images

ObjectiveThe purpose of this study is to examine the time-related changes of alveolar bone in 2D images quantitatively and to estimate age groups based on the change index. Materials and methodsThe 238 panoramic X-ray images and 140 CT panoramic reconstructed images of the permanent dentition period were used to examine age-related changes. Comparisons between the younger age group and each of the other age groups were calculated using the landmark method of Procrustes analysis. As aging changes were observed in each age group, age estimation was performed using antemortem panoramic X-ray images and postmortem CT images so that they could be used in practice. The CT images used in the age estimation were performed using forty-two postmortem CT panoramic reconstructed images of known age submitted to the judicial autopsy. ResultsBoth panoramic and CT images showed changes in the alveolar bone over time. Age estimation using postmortem CT images provided a certain assessment. ConclusionIn this study, clinically observed changes in alveolar bone over time were quantified on the images. Furthermore, the possibility of age estimation by alveolar bone was also suggested. The use of an updatable clinical database that can be stored in coordinate values offers the potential for age estimation in line with the times.

Retrospective denoising and sharpening effects on postmortem computed tomography images of formalin-fixed human cadavers for human anatomy education and research

BackgroundThe value of formalin-fixed postmortem computed tomography (PMCT) has significantly increased in human anatomy education and research. However, improving embalmed PMCT images with high noise, low contrast, and multiple artifacts is an important challenge in enhancing the quality of clinical images. Retrospective denoising methods for embalmed PMCT data are essential for anatomical education and research when new-generation CT scanners with denoising functions are unavailable. MethodsThe three currently available standalone software denoising methods, including image summation methods (Fused CT), noise-reduction system methods (iNoir), and iterative reconstruction (IR, SafeCT), were used to analyze the retrospective noise-reduction effect on 13 human formalin-fixed PMCT datasets. ResultsFused CT had some advantages; however, it was not useful for embalmed cadavers because of high noise, which doubled with the addition. iNoir and SafeCT improved the visual image quality of the noisy cadaver images. Statistical examination showed a 22–67 % and 18–56 % improvement in noise reduction in the non-artifact and metal artifact parts, respectively, depending on the methods and denoising intensities. However, this improvement was not statistically or morphologically significant in the presence of strong metal artifacts. In contrast, the scattered metal and streak artifacts peculiar to cadaveric images showed effective morphological and statistical improvement. ConclusionsRetrospective denoising of embalmed PMCT images showed significant morphological and statistical improvements in noise reduction and is feasible for current anatomy education and research.

Postmortem Computed Tomography – Based Body Weight Estimation in Korean Infants Using Volume and Multiplication Factors

Postmortem computed tomography (PMCT) is used in forensic medicine worldwide due to its ability to non-invasively visualize injuries, hemorrhage, and estimate volume. In the autopsy of infants, assessing nutritional conditions such as weight is crucial for identifying neglect. This study aims to evaluate the usefulness of retrospectively estimating the weight of Korean infants using PMCT-based volume and multiplication factors, even when the body has been cremated. A total of 44 cases of infant death (under 12 months) were analyzed. PMCT images were obtained before autopsy. Autopsy records and documentation provided by the police at the time of autopsy were reviewed to determine the weight (g) of the infant. PMCT-based infant volumes (mL) were estimated using a three-dimensional semi-automatic segmentation method. Multiplication factors (g/mL) were calculated by dividing the weight recorded at autopsy by the PMCT-based volume, yielding a mean of 1.047 g/mL, ranging from 1.014 g/mL to 1.085 g/mL. The mean absolute error compared to weights recorded at autopsy was 95 g. Significant discrepancies were observed between weights recorded at the scene or medical center and those measured at autopsy. This study demonstrates that PMCT-based weight estimation for Korean infants is a reliable method and has the potential for retrospectively validating incorrect weight measurements and addressing inconsistencies in recorded weight data.

Illustrated cross-sectional computed tomography of the cetacean abdomino-pelvic organs

Computed tomography (CT) is a non-invasive diagnostic imaging modality which can be used to study the anatomy and morphology of live or deceased animals in-situ. In cetaceans, existing CT anatomy studies mostly focused on the head and thoracic regions. Using postmortem CT (PMCT) scans of Indo-Pacific finless porpoises (Neophocaena phocaenoides), this study describes the cross-sectional imaging anatomy of the cetacean abdomino-pelvic organs for the first time. PMCT scans of finless porpoises stranded in Hong Kong waters were reviewed, of which two freshly dead cases, one male and one female, were selected for illustration. In addition, a contrast-enhanced PMCT scan was performed on the female subject as a trial for a PMCT-angiography study (PMCTA) in cetaceans. A total of 18 axial PMCT images were acquired at selected vertebral levels in the abdomen and supplemented with a series of corresponding labeled anatomical diagrams. By applying different image rendering techniques, most osseous and soft tissue structures in the finless porpoise abdomen were successfully depicted and annotated on PMCT, including the male and female reproductive organs in the pelvic region. The application of contrast medium in PMCT created artificial radiodensity differences which improved the ability to visualize and differentiate soft organs and vasculature. The merits and limitations of CT compared to other imaging modalities, as well as the future directions of PMCT in stranding investigation, were discussed. The findings from this study significantly enhance the applications of CT in cetaceans by assisting researchers and veterinarians in the interpretation of cetacean abdomino-pelvic CT for morphological and pathological assessment during clinical or postmortem examination.

An atypical case of fatal ‘esophageal apoplexy’: post-mortem findings and differential diagnosis

Forensic pathologists need to have comprehensive knowledge of a large variety of causes of sudden natural death. We describe a case of sudden and unexpected death in woman in her sixties due to rupture of a large paraesophageal hematoma. The post-mortem examination and differential diagnosis are discussed. The combined findings of whole-body post-mortem CT imaging (PMCT), targeted PMCT angiography, autopsy, and histology are most in keeping with ‘esophageal apoplexy’; a rare cause of hemorrhage in the esophageal wall. A review of the literature indicates that most cases of esophageal apoplexy are self-limiting and that fatal complications are exceedingly rare. Our case demonstrates that esophageal apoplexy can present as sudden unexpected death.

Postmortem changes in the eye on computed tomography images

BackgroundOcular tension decreases with increasing postmortem interval (PMI) and eyes collapse with extreme progression of postmortem change; however, time-related changes in postmortem computed tomography (PMCT) findings have not been clarified. This study aimed to quantitatively evaluate the vitreous volume and CT values of the vitreous body to clarify time-related changes in PMCT. MethodsWe retrospectively reviewed PMCT images of the eyes of subjects who underwent autopsy at our institution between July 2023 and February 2024. They were classified into four PMI groups: PMI-1: < 1 day, PMI-2: 1–2 days, PMI-3: 3–6 days, PMI-4: ≥ 7 days. The vitreous volumes and mean CT values of the vitreous chambers were measured. Additionally, the presence of intraocular gas and crystalline lens dislocation was observed. ResultsThe PMCT images of 131 eyes of 66 patients (41 males, 25 females) were analyzed. The mean age was 63.7 (22–99) years. The volume of the vitreous cavity was significantly decreased at PMI-3 and PMI-4, which indicated scleral depression. Intraocular gas appeared in PMI-4. Lens dislocation began at PMI-3 and was more frequently observed at PMI-4 and in the higher-temperature environment group. ConclusionOcular findings on PMCT are useful for estimating the time of death.

Advanced medical imaging for forensic triage: A study of the added value of combining PMCT and PMMR of the head

BackgroundApproximately 170,000 individuals die annually in the Netherlands. Dutch law mandates examinations to distinguish between natural death and unnatural death. Traditionally, this involves external examinations and an inspection of medical records; however, medical imaging has emerged as a tool for investigating deaths. ObjectiveThe objective of the study was to investigate whether the addition of post-mortem magnetic resonance (PMMR) to post-mortem computed tomography (PMCT) could assist in the categorisation of deaths as natural or unnatural and augment confidence in those classifications. MethodsIn this retrospective study, the PMCT and PMMR head images of 50 individuals were evaluated by a forensic radiologist. The impact of PMMR on lesion detection, the cause of death (COD), the differentiation between natural death and unnatural death, and confidence levels were assessed. All available case information was used as the reference standard. ResultsThe addition of the PMMR led to a statistically significant increase in lesion detection (48%), changes in the classification of COD in four cases, and an increased level of confidence in the classification. Differentiation between natural death and unnatural death reversed in 10 cases, altering the overall manner of death (MOD) classification in 20% of cases. ConclusionWhen PMCT indicates a natural or unnatural death, PMMR is unnecessary. PMMR of the head is recommended in situations in which the MOD is uncertain based on PMCT findings. The ultimate determination of a natural death and unnatural death should always take into account the results of external examinations, police investigations, and other available information.

Performance of postmortem CT in the diagnosis of natural death from out-of-hospital cardiac arrest.

Postmortem CT (PMCT) is used widely to identify the cause of death. However, its diagnostic performance in cases of natural death from out-of-hospital cardiac arrest (OHCA) may be unsatisfactory because the cause tends to be cardiogenic and cannot be detected on PMCT images. We retrospectively investigated the diagnostic performance of PMCT in the diagnosis of natural death from OHCA and compared it to that of unnatural death. Our series included 450 cases; 336 were natural- and 114 were unnatural death cases. Between 2018 and 2022 all underwent non-contrast PMCT to identify the cause of death. Two radiologists reviewed the PMCT images and categorized them as diagnostic (PMCT alone sufficient to determine the cause of death), suggestive (the cause of death was suggested but additional information was needed), and non-diagnostic (the cause of death could not be determined on PMCT images). The diagnostic performance of PMCT was defined by the percentage of diagnosable and suggestive cases and compared between natural- and unnatural death cases. Interobserver agreement for the cause of death on PMCT images was also assessed with the Cohen kappa coefficient of concordance. The diagnostic performance of PMCT for the cause of natural- and unnatural deaths from OHCA was 30.3% and 66.6%, respectively (p < 0.01). The interobserver agreement for the cause of natural- and unnatural deaths on PMCT images was very good with kappa value 0.92 and 0.96, respectively. As PMCT identified the cause of natural death by OHCA in only 30% of cases, its diagnostic performance must be improved.

The cardiothoracic ratio on postmortem CT as a screening tool for cardiomegaly in the Thai population.

IntroductionIn forensic radiology, the cardiothoracic ratio (CTR) calculated from postmortem computed tomography (PMCT) images can be used to detect cardiomegaly. In this study, a new measurement method is studied that involves measurement in the anteroposterior (AP) and transverse directions, with a reference level based on the Thai population. ObjectiveTo screen for cardiomegaly using the CTR calculated from PMCT images. Research methodA sample size of 116 deceased Thai individuals who underwent PMCT before autopsy was obtained. Individuals were divided into two groups: normal heart weight and overweight heart. Hearts heavier than the mean plus one standard deviation were categorized into the overweight group. The CTR was calculated in both the AP and transverse directions at six reference levels. Receiver operating characteristic curves (ROC) were calculated to determine the CTR cutoff point for the diagnosis of cardiomegaly. ResultsThe CTR cutoff values for diagnosing cardiomegaly were as follows: 1) CTR >0.5 in the transverse direction at the mid-vertebra of T7 (sensitivity, 75.6%; specificity, 70.6%; area under the ROC curve 0.81), 2) CTR >0.49 in the transverse direction at the mid-vertebra of T8 (sensitivity 71%, specificity 81.4%, area under the ROC curve 0.80). The selection of the cutoff values depended on the location of the heart. The area under the ROC curve in the AP direction was in the range 0.5-0.7, which is inferior compared to the transverse direction (0.7-0.9). ConclusionCalculating the CTR with a reference level on PMCT images can assist in the diagnosis of cardiomegaly.

Forensic significance and inferential value of PMCT features in charred bodies: A bicentric study

Post-mortem computed tomography (PMCT) is a diagnostic tool that provides essential information in forensic field. This radiological technique can play a pivotal role in personal identification, gunshot injuries, major traumatic injuries, child abuse, drowning asphyxia, embolism, COVID-19, sudden death, and charring cases.Post-mortem imaging can be used to investigate charred bodies as it allows the forensic examiner to distinguish traumatic and heat injuries. PMCT images can also provide additional information to determine whether the individual was alive at the time the fire started.In our bicentric study, we performed PMCT on 15 cases of charred bodies (10 males and 5 females) collected at the Florence University (Florence, Italy) and Catholic University of The Sacred Heart (Rome, Italy) before the external examination and/or full autopsy examination. In both the institutions, PMCT was performed through a Siemens SOMATOM 16-slice CT scanner (Siemens Aktiengesellschaft, Berlin, 2010).The aim of the current study was to obtain unambiguous information that could help determine the cause of death by comparing our PMCT findings with the most recent evidence in the scientific literature. Our investigations focused on the evaluation of bone texture and differences from traumatic fractures, leading also to an improvement in the interpretation of some aspecific findings (e.g., soot) from the integration of the radiological information with the autopsy results.The data obtained in our study support PMCT as a reliable diagnostic tool in the study of charred corpses and represent basic evidence for further applications of radiology in the forensic field.

U-Net-Based Automatic Segmentation of Sphenoid Sinus Fluid in Drowning Cases Using Postmortem CT Images: A Feasibility Study

Detecting sphenoid sinus fluid (SSF) is an additional finding in autopsies for diagnosing drowning. SSF can provide additional forensic evidence through laboratory tests such as diatom and electrolyte analyses. If drowning is suspected, accurately assessing the presence and volume of SSF during an autopsy is crucial. Utilizing postmortem computed tomography (PMCT) images could aid in accurately sampling SSF. Accurately segmenting the region of interest is essential for volume analysis using computed tomography images. However, manual segmentation techniques are labor-intensive and time-consuming, and their success depends on the experience of the observer. Therefore, this study aimed to develop a U-Net–based deep learning model for the automatic segmentation of SSF in drowning cases using PMCT images and to evaluate the performance of the model. We retrospectively reviewed 34 drowning cases in which both PMCT scans and forensic autopsies were performed at our institution. The U-Net architecture of deep learning was used for automatic segmentation. The proposed model achieved the Dice similarity coefficient (DSC) and Intersection over Union (IoU) of a maximum of 95.85% and 92.03%, a minimum of 0% and 0%, and an average of 77.15% and 67.18%, respectively. Although the average DSC and IoU did not show high similarity, this study showed that PMCT images can be used for automatic segmentation of SSF in drowning cases, which could improve the performance with sufficient dataset acquisition and further model training.

Distinguishing true from pseudo hematoma in the cervical spinal canal using post-mortem computed tomography

Spinal cord injury is difficult to detect directly on postmortem computed tomography (PMCT) and it is usually diagnosed by indirect findings such as a hematoma in the spinal canal. However, we have encountered cases where the hematoma-like high-attenuation area in the cervical spinal canal was visible on PMCT, while no hematoma was observed at autopsy; we called it a “pseudo hematoma in the cervical spinal canal (pseudo-HCSC).” In this retrospective study, we performed statistical analysis to distinguish true from pseudo-HCSC. The cervical spinal canal was dissected in 35 autopsy cases with a hematoma-like high-attenuation area (CT values 60-100 Hounsfield Unit (HU)) in the spinal canal from the first to the fourth cervical vertebrae in axial slices of PMCT images. Of these 22 had a hematoma and 13 did not (pseudo-HCSC). The location and length of the hematoma-like high-attenuation and spinal cord areas were assessed on reconstructed PMCT images, true HCSC cases had longer the posterior hematoma-like area and shorter the spinal cord area in the midline of the spinal canal (P < 0.05). Furthermore, we found that true HCSC cases were more likely to have fractures and gases on PMCT while pseudo-HCSC cases were more likely to have significant facial congestion (P < 0.05). We suggest that pseudo-HCSC on PMCT is related to congestion of the internal vertebral venous plexus. This study raises awareness about the importance of distinguishing true HCSC from pseudo-HCSC in PMCT diagnosis, and it also presents methods for differentiation between these two groups.

Pericardial Effusion Detection on Post-Mortem Computed Tomography Images Using Convolutional Neural Networks.

Pericardial effusion can be a sign of significant underlying diease and, in some cases, may lead to death. Post-mortem computed tomography (PMCT) is a well-established tool to assist death investigation processes in the forensic setting. In practice, the scarcity of well-trained radiologists is a challenge in processing raw whole-body PMCT images for pericardial effusion detection. In this work, we propose a Pericardial Effusion Automatic Detection (PEAD) framework to automatically process raw whole-body PMCT images to filter out the irrelevant images with heart organ absent and focus on pericardial effusion detection. In PEAD, the standard convolutional neural network architectures of VGG and ResNet are carefully modified to fit the specific characteristics of PMCT images. The experimental results prove the effectiveness of the proposed framework and modified models. The modified VGG and ResNet models achieved superior detection accuracy than the standard architecture with reduced processing speed.

Forensic age estimation of the knee by post-mortem DR, CT, and MR imaging: a comparative study

It is believed by many that reference data for age estimation purposes must be imaging-modality specific. A study from our department has however proven otherwise. We therefore found it interesting to investigate this further by looking at the level of agreement between different imaging modalities. The aim of this study was to investigate the level of agreement between the three radiological modalities, computed tomography (CT), magnetic resonance imaging (MRI), and digital radiography (DR), in assessing the ossification of the epiphyses of the knee. A total of 34 deceased individuals of 10–25 years of age, brought in for a medicolegal autopsy at our department, were scanned by CT, MRI, and DR. The ossification stages of the three bones of the right knee, distal femoral, proximal tibial, and proximal fibular epiphysis were assessed using the established combined staging method by Schmeling et al. and Kellinghaus et al. Analysis of the results by Cohen’s weighted kappa showed a good agreement between CT and DR (K = 0.61–0.70), and MRI and DR (K = 0.68–0.79) but only moderate agreement between CT and MRI (K = 0.55–0.57). This leads us to conclude that different radiological images cannot be used interchangeably for age estimation purposes, so reference material needs to be imaging-modality specific. However, to make a more general conclusion research on a larger population is needed.

Classification of rib fracture types from postmortem computed tomography images using deep learning.

Human or time resources can sometimes fall short in medical image diagnostics, and analyzing images in full detail can be a challenging task. With recent advances in artificial intelligence, an increasing number of systems have been developed to assist clinicians in their work. In this study, the objective was to train a model that can distinguish between various fracture types on different levels of hierarchical taxonomy and detect them on 2D-image representations of volumetric postmortem computed tomography (PMCT) data. We used a deep learning model based on the ResNet50 architecture that was pretrained on ImageNet data, and we used transfer learning to fine-tune it to our specific task. We trained our model to distinguish between "displaced," "nondisplaced," "ad latus," "ad longitudinem cum contractione," and "ad longitudinem cum distractione" fractures. Radiographs with no fractures were correctly predicted in 95-99% of cases. Nondisplaced fractures were correctly predicted in 80-86% of cases. Displaced fractures of the "ad latus" type were correctly predicted in 17-18% of cases. The other two displaced types of fractures, "ad longitudinem cum contractione" and "ad longitudinem cum distractione," were correctly predicted in 70-75% and 64-75% of cases, respectively. The model achieved the best performance when the level of hierarchical taxonomy was high, while it had more difficulties when the level of hierarchical taxonomy was lower. Overall, deep learning techniques constitute a reliable solution for forensic pathologists and medical practitioners seeking to reduce workload.

Estimation of missing mandible from the skull using postmortem CT images

Skeletal remains often have missing mandibles owing to the environment in which the corpse was placed or damage caused by an animal. Loss of the mandible reduces the accuracy of skull identification. Although several studies have validated methods for estimating mandibular morphology from conventional anthropological measurements using skull specimens, there are no reports using three-dimensional computed tomography (3DCT) images. Here, we examined methods for establishing the mandibular morphology from the remaining skulls using postmortem computed tomography (PMCT) images. We used PMCT images from 200 Japanese subjects as samples. After verifying the morphological correlation between the cranium and mandible, we created and validated estimation models using multiple regression analysis (stepwise method) for seven sites that were necessary for understanding the morphology of the mandible. Among the regression models, the estimated model for bicondylar breadth had the highest coefficient of determination (adjR2 = 0.53). We verified the accuracy of the model on a sample independent from the specimen used to create the estimation model and found that the formulated model of bicondylar breadth had good estimation accuracy, with a high correlation coefficient between the measured and predicted values of 0.82 and a mean absolute error of 3.582 mm, indicating that the model had good estimation accuracy. Here, we established a novel method for estimating the missing mandibular morphology based on PMCT data from the Japanese population. Our estimation model can help determine the missing mandibular morphology in a cranium remnant.

Objective Evaluation of Oral and Pharyngeal Areas in Autopsy Cases of Obstructive Sleep Apnea Syndrome via Postmortem CT.

Obstructive sleep apnea syndrome (OSAS) can cause sudden death during sleep. Previous findings have suggested that OSAS development is related to maxillofacial morphology. Evaluation of facial morphology can determine the risk of developing the disease, and establishing an objective method to assess the underlying etiology of OSAS-related death would be advantageous. The objective of this study is to determine the key features of obstructive sleep apnea syndrome (OSAS) using postmortem oral and pharyngeal computed tomography (CT). We retrospectively assessed autopsy cases of patients with (n=25) and without (n=25) OSAS-related death. We used oral and pharyngeal CT images to compare the oral and pharyngeal cavity volume (OPCV), oral and pharyngeal soft tissue volume (OPSV), oral and pharyngeal air space volume (OPAV), and OPAV to OPCV ratio (%air). Receiver operating curve (ROC) analysis was used to determine the accuracy of OSAS prediction. We assessed participants with body mass index (BMI) values within the normal range. Among the 50 subjects, we observed significant between-group differences in OPSV, OPAV, and % air, whereas there were significant between-group differences in OPSV and %air among 28 subjects with normal BMI values. Both comparisons suggested that OSAS-related death was associated with low %air and high OPSV values. The %air and OPSV are useful for assessing postmortem oropharyngeal CT images. OSAS-related sudden death is likely when %air and OPSV values are ≤20.1% and ≥127.2 ml, respectively. Among those with normal BMI values, % air and OPSV values of ≤22.8% and ≥111.5 ml, respectively, predict OSAS-related sudden death.

Simplified Formula for Estimating Nasal Dimensions for 3-Dimensional Facial Reconstruction among Japanese Adults

The eyelids, external nose, and lips play an important role in individual identification and facial recognition; however, they are excluded from tissue marker points, and are reconstructed based on generic methods for 3D facial reconstruction or facial approximation. Therefore, this study focused on nasal dimensions and evaluated whether Krogman’s widely used formula for estimating the dimensions of an external nose, regardless of sex, race, and body physique, can be applied to Japanese adults. A total of 146 postmortem CT images of Japanese adult cadavers (64 males and 82 females, aged 58–105 years old) were retrospectively analyzed. The total nasal projection (TNP) among Japanese adults was estimated using the formula, TNP = 1.9 × the anterior nasal spine projection (ANSP) + the mid-philtrum depth (MPD), which differed significantly from the coefficient (3.0) in the conventional formula, regardless of sex, race, and body physique, and therefore needed modification for Asians. Although there was no positive relationship between the total nasal width (TNW) and the maximum width of the anterior nasal aperture (ANAW), the TNW could be estimated by adding soft tissue that varies by sex and body physique to both sides of the nearly constant ANAW. Therefore, we determined a simple and practical formula to estimate nasal dimensions among Japanese adults for conventional 3D facial reconstruction and manual 3D facial sculpture.