Estimating age at death by Hausdorff distance analyses of the fourth lumbar vertebral bodies using 3D postmortem CT images.

The existing methods for determining adult age from human skeletons are mostly qualitative. However, a shift in quantifying age-related skeletal morphology on a quantitative scale is emerging. This study describes an intuitive variable extraction technique and quantifies skeletal morphology in continuous data to understand their aging pattern. A total of 200 postmortem CT images from the deceased aged 25-99 years (130 males, 70 females) who underwent forensic death investigations were used in the study. The 3D volume of the fourth lumbar vertebral body was segmented, smoothed, and post-processed using the open-source software ITK-SNAP and MeshLab, respectively. To measure the extent of 3D shape deformity due to aging, the Hausdorff distance (HD) analysis was performed. In our context, the maximum Hausdorff distance (maxHD) was chosen as a metric, which was subsequently studied for its correlation with age at death. A strong statistically significant positive correlation (P < 0.001) between maxHD and age at death was observed in both sexes (Spearman's rho = 0.742, male; Spearman's rho = 0.729, female). In simple linear regression analyses, the regression equations obtained yielded the standard error of estimates of 12.5 years and 13.1 years for males and females, respectively. Our study demonstrated that age-related vertebral morphology could be described using the HD method. Moreover, it encourages further studies with larger sample sizes and on other population backgrounds to validate the methodology.

A novel method to estimate adult age from the lumbar vertebral body using 3D PMCT images in Japanese.

This study evaluated the age-related changes in the vertebral body using 3D Postmortem CT (PMCT) images and proposed an alternative age estimation formula. The PMCT images of 200 deceased individuals aged 25 to 99 years (126 males, 74 females) were retrospectively reviewed and included in the study. Using the open-source software ITK-SNAP and MeshLab, a 3D surface mesh of the fourth lumbar vertebral body (L4) and its convex hull models were created from the PMCT data. Using their inbuilt tools, volumes (in mm3) of the L4 surface mesh and convex hull models were subsequently computed. We derived VD, defined as the difference in volumes between the convex hull and L4 surface mesh normalized by L4 mesh volume, and VR, defined as the ratio of L4 mesh volume to convex hull volume based on individual L4. Correlation and regression analyses were performed between VD, VR, and chronological age. A statistically significant positive correlation (P < 0.001) between chronological age and VD, (rs = 0.764, males; rs = 0.725, females), and a significant negative correlation between chronological age and VR (rs = -0.764, males; rs = -0.725, females) was obtained in both sexes. The lowest standard error of the estimate was demonstrated by the VR at 11.9 years and 12.5 years for males and females, respectively. As such, their regression models to estimate adult age were Age = 248.9-2.5VR years, males; Age = 258.1-2.5VR years, females. These regression equations may be useful for estimating age in Japanese adults in forensic settings.

Development of New Formulas for Sex and Age Estimation by Assessing Maxillary Sinus Morphology on CBCT.

Background: The morphology of the maxillary sinus varies between individuals which could be used in the forensic personal identification process. Methods: In the current study, the CBCT images of the maxillary sinus in 453 patients (217 males, 236 females) aged 14 to 95 years were analyzed. In particular, each left, and right maxillary sinus of the subjects was measured for its maximum height, width, and breadth in 2-D, and volume in 3-D perspectives, and their usefulness for age and sex estimation was examined. Regarding age estimation, because the size of the maxillary sinus increases up to 20s and then decreases over time, two separate age estimation formulas were created, one for subjects in their 14-21 years and the other for those over 22 years old. For each age group, multiple regression formulas were generated using the diameters and volume as explanatory variables and the chronological age as a response variable. This study used 150 cases not included in the study as a validation set for age estimation. Results: Generally, all the diameters and volumes in both sinuses tended to increase till the mid-20s, and then gradually decreased over time. The derived formulas were tested for their accuracy on additional 150 subjects. Plausibly, the model could estimate the age between 14-21 years old with an average accuracy of ± 1.8 years for men and ± 3.2 years for women. Whereas for those over 22 years old, it was possible to estimate the age with an accuracy of ± 11.8 years for males and ± 10.3 years for females, respectively. A comparison of estimated age and chronological age did not show a statistically significant difference(P > 0.05). It was found that the left maxillary sinus had more age groups showing the most significant difference than other measurements between sexes(P < 0.05). The maxillary sinus height may be significantly affected by gender differences. Conclusion: Overall, this study showed the effectiveness of age and sex estimation using the maxillary sinus morphometric analyses.

Implementation of a personal identification system using alveolar bone images.

OBJECTIVE: In recent years, personal identification has been performed using antemortem panoramic X-ray images and postmortem-CT images. Using these, we have developed a personal identification method that focuses on the alveolar bone. This study examined the effectiveness of this method and aimed to implement a reproducible system. MATERIALS AND METHODS: For personal identification, a total of 633 CT images and panoramic X-ray images belonging to three groups with different conditions were used.　These images were 160 sets in the same person group and 96,820 in the other groups. The similarity of alveolar bone images was calculated using the landmark method of Procrustes analysis. The processes were system implemented and the methodology was validated. RESULTS: The ability to identify between the same person group and other person groups showed 0.9769 as the area under the curve (AUC: ROC curve). At the cutoff value of 4.978, there was no false rejection rate, but false acceptance rate was slightly higher. CONCLUSION: This method was useful as a screening method for personal identification. In addition, system implementation was efficient and reduced human error. In the future, we aim to realize a more efficient personal identification method using distortion-corrected images and including auto-detective landmarks using deep learning.

Vascular anatomy and their variations in Situs inversus totalis using postmortem computed tomographic angiography.

Studies describing the vascular systems and their variations in Situs inversus totalis (SIT) from a whole-body computed tomographic (CT) angiography perspective are lacking. We report a case of SIT in which postmortem CT angiography (PMCTA) was performed as a part of the forensic death investigation and incidentally detected several vascular variations in it. The PMCTA procedure was performed using the multiphase PMCTA protocol. Almost all major vessels were visualized, indeed in a completely reversed pattern. Contrast mixture flow interruptions were noted in the right coronary arterial branches suggesting possible blockage, upon which autopsy revealed >90% vessel occlusions at several locations. As such the cause of death was due to ischemic heart disease. Anomalous origins of the right internal mammary artery; abnormal left thyrocervical trunk and variations in the drainage of testicular veins were noted. Our findings might be helpful to clinicians and add to the body of literature on SIT.

Forensic Medicine in South Asia: Comparison to the Developed Countries.

This study attempted to discuss the historical context and current practice of forensic medicine in South Asia. Comparisons within and between countries in South Asia, and between South Asia and the developed countries (represented by Japan and the USA) have been made to provide an insight into their distinct practice of forensic medicine. Though the formal establishment of forensic medicine in South Asia commenced at a comparable period to the developed countries, their pace of development has been considerably slow. Moreover, their ways of practice as well have evolved differently. In effect, South Asian countries follow an 'integrated service' system, whilst Japan and the USA practice 'divided service' systems to provide forensic medical services. Similarly, regarding the death investigations, most South Asian countries follow a Police-led death investigation system, whereas Japan and the USA follow a hybrid model and the Medical examiner's system of death investigation, respectively. Indeed, forensic medicine in South Asia is undeniably underdeveloped. In this paper, by highlighting the issues and challenges confronted in South Asia, key actions for prompt redressal are discussed to improve the standard of forensic medical services in South Asia.

Estimation of Postcardiac Arrest Interval Based on Atrial Cavity Density in Postmortem Computed Tomography.

BACKGROUND: Intracardiac hypostasis is frequently observed in postmortem computed tomography (PMCT) of acute deaths, and it becomes clearer as the postmortem interval increases. To determine the postcardiac arrest interval (PCAI), we evaluated densities of the right and left atria [anterior part of the right atrium (AR) and posterior part of the left atrium (PL)] using postmortem computed tomographic images. METHODS: A total of 184 patients were included in the study. Patients with return of spontaneous circulation and those with final alive confirmation time over 1 hour were excluded. We evaluated the density of AR and PL at the level of the right inferior pulmonary vein entry to the left atrium. We defined the interval between the estimated cardiac arrest time and the postmortem CT time as the PCAI. RESULTS: There was a negative correlation between AR and PCAI in 59 patients who died owing to cardiovascular disease. The regression equation (PCAI = -1.725 × AR + 132.95) was obtained based on this result. There was no correlation between PL and PCAI. CONCLUSION: The result suggests that the density of the anterior part of the right atrium decreases as postcardiac arrest interval increases in the case of cardiovascular disease. The regression equation may be used as an additional method to estimate postcardiac arrest interval.