Forensic Imaging最新文献

Background & Objectives

In light of imaging evidence on the differences in several characteristics of anatomical foramina in the mandible, the current study evaluates the morphologic and morphometric characteristics of Mental foramen (MF) by Cone-Beam Computed Tomography (CBCT) in an Eastern Indian population as well as the effect(s) of age and gender on the same.

Material and Methods

CBCT images of 200 adult individuals aged 18–60 years were examined for the position, opening angle, dimensions of MF; vertical distance from the superior border of the foramen to alveolar crest and inferior border to base of the mandible; and the prevalence of the accessory mental foramen (AMF). The characteristics of MF and AMF were compared across the gender and age groups at p < 0.05 level of significance.

Results

The MF was positioned in between the roots of premolars in 48.0% and 44.0% of males and females, respectively. In a higher proportion of females (98.0%, p = 0.006), the vertical position of MF on the left-side was below the root apex. The vertical (3.64 millimeter; p < 0.001) and horizontal (3.64 millimeter; p < 0.001) diameters of MF and occurrence of AMF (16.0%, p = 0.046) on the left-side were higher in males. The opening angle of MF (right-side: 24.13 degrees, p = 0.001; left-side: 24.21 degrees, p < 0.001) was higher in females.

Conclusion

Significant variations in certain parameters of the MF across gender were revealed with marked prevalence of AMF that may be of value in forensic investigation.

Introduction

Identification of individuals is a crucial aspect of forensic medicine. Due to the durability of bones, they are regarded as an ideal investigative tool, particularly in complex cases where other body parts are highly degraded.

Aim

This study aims to predict sex based on skull CT scan measurements in Iranian ethnicity by a machine learning-based model. We try to depict skull sexual differences and propose new analytic methods based on machine learning, to improve the efficacy of personal identification.

Method

Eight variables were measured from skull CT images of 199 Iranians, including 118 males with a mean age of 56.4 years and 81 females with a mean age of 55.2 years. Craniometric data were analyzed by conventional logistic regression and the Gradient Boosting Decision Trees method.

Results

According to statistical analysis utilizing a univariate logistic regression model, the LCB, LFCB, and BD indices had a statistically significant impact on the final sex prediction of the subject. With an AUC of 0.83, this model's overall accuracy for sex prediction was 83%. The gradient boosting model outperformed logistic regression, with AUC and accuracy values of 0.94 and 0.89, respectively, which were higher than those of logistic regression. In the gradient boosting model, LFCB, BD, and LCB were also the most important craniometrics.

Conclusion

This study demonstrates sexual differences in the Iranian population and the high accuracy of the Gradient Boosting model in sex identification based on these differences.

The frontal sinuses are commonly used in sexual estimation due to the considerable variation in size, shape and number. Previous studies have shown average accuracy measuring frontal sinus area, height and width; however, authors have associated such measurements with the frontal sinus index, obtaining better results. Therefore, the aim of the present study was to evaluate sexual dimorphism of the frontal sinus in Brazilian adults. The sample consisted of 255 lateral cephalometric radiographs of subjects between 20 and 40 years of age, 132 females and 123 males. Based on the methodology of Luo et al. (2018), the area (S) and the maximum frontal sinus height and width (AB and EF, respectively) were measured using computer-aided design software; and the ratio between AB and EF was taken as the frontal sinus index (R). The discriminant function developed by the authors was then applied to evaluate sexual dimorphism in the Brazilian population. Descriptive statistics were performed for the variables according to gender, as well as Student's t-test and the Mann-Whitney test to see if there was a difference between the variables. A new discriminant formula was calculated with the study data and machine learning techniques, neural networks and decision trees, were used to improve the prediction of sex. The variables showed significant differences in relation to gender, and with the exception of R, where the male mean was 2.00 and the female mean was 2.40, all the means were higher for males. The original formula of the study had low accuracy, with a level of accuracy of only 8.33% for females. However, the formula calculated for Brazilians presented an accuracy of 70.20%; of the machine learning techniques, only the neural network presented a higher value than the one already obtained, of 73.30%. In conclusion, the new formula showed an accuracy of 70.20% and can be applied as an auxiliary method in the assessment of frontal sinus sexual dimorphism in Brazilian adults.

Objectives

The cardiothoracic ratio (CTR) is a useful technique to investigate the prevalence of cardiomegaly, an important clinical manifestation of several cardiovascular diseases. The aim of this study was to determine the relationship between various macroscopic measurements of heart size on postmortem chest X-rays and CTR as well as develop a new CTR threshold or scoring system to improve reliability of CTR in forensic settings.

Materials and methods

We selected 131 forensic autopsy cases aged more than 18. The heart length and width, wall thicknesses, chamber diameters, and heart weights were measured during autopsy. The postmortem CTR was measured in an anteroposterior chest radiography. In autopsy cases among the Thai population, two groups were defined: normal and overweight heart, with cut-off values based on average heart weight + 1SD.

Results

The results showed that the wall thickness and chamber diameter were not related to CTR, but the heart length and width were. A multivariable analysis was performed and showed good discriminating power, with an area under the ROC curve of 0.88. A new formula was developed, which included age, BMI, and CTR. The recommend cut-off score was 122 for the diagnosis of cardiomegaly, in which the sensitivity and specificity were 78.3% and 72.9%.

Conclusions

The findings of increased CTR cannot be equated to cardiac wall hypertrophy and chamber enlargement. This study suggests that a combination of CTR, BMI, and age of the deceased improves the level of discrimination between the condition of normal heart and cardiomegaly before autopsy.

Introduction

Ventilated PMCT (VPMCT) has been reported to provide better quality of pulmonary structures in PMCT in adults and children. However, there are no consensus regarding optimal inflation pressure, and the practical use of VPMCT is still limited by cost of ventilation equipment. Here, we describe a simple and cost-efficient inflation-device for VPMCT and investigate optimal inflation pressure.

Aim

To elucidate the effect of different ventilation pressures on total lung volume and the volume of ground glass opacities (GGO), air-filled tissue, consolidations, and bronchi in VPMCT.

Materials and method

A precise inflation device was assembled using standard components: a back-pressure regulator, a water manometer and silicone tubing. Each case had PMCT performed at 0, 10, 20, 30 and 40 cmH₂O pressure. Volumes were measured using stereology.

Results

14 cases were enrolled in the study. The total lung volume increased significantly by 3612 mL (median) from 0 to 30 cmH₂O (p = 0.001). The volume of consolidations was significantly reduced by 455.86 mL (median) between 0 and 30 cmH₂O (p = 0.001). A significant reduction of GGO-volume of 133 mL (median) was observed at the pressure interval 30–40 cmH₂O (p = 0.031), but not at lower pressures.

Conclusion

The constructed inflation device allowed precise and reproducible inflation of the lungs in deceased humans. We found a maximum effect of inflation at 30 cmH₂O. At further inflation pressure, only the volume of GGOs decreased , but the effect was minor. For mimicking an in vivo breath-hold scan in PMCT we recommend inflation pressure of 30 cmH₂O.

Background

The value of post-mortem computed tomography (PMCT) in trauma victims is well established. In this review the diagnostic accuracy and value of PMCT will be investigated specifically for fire related deaths, which has yet to be fully investigated.

Methods

PRISMA guidelines informed this systematic review. A total of ten databases were searched in December 2020. All articles exploring the use of PMCT and autopsy to investigate fire related deaths in adults were deemed eligible for inclusion, and were reviewed by two independent researchers. The QUADAS-2 tool was used to assess the quality of these papers.

Results

Seven studies were selected, containing a total of 110 burns victims. PMCT was superior in identifying fractures, and is particularly accurate with regards to fractures and injuries of the skull, facial bones, neck and extremities. However, PMCT fared poorly in identifying signs of vitality during a fire compared to autopsy. Toxicological examinations to assess carbon monoxide levels were often still required to make a conclusive diagnosis of fire as the cause of death.

Conclusions

Despite the heterogeneity of the methodologies’ reviewed, it is clear that PMCT is an extremely powerful visualisation tool with great potential for documentation and examination in forensic cases. The limitations of PMCT mean that it can not fully replace autopsy in these cases, but if autopsy is not available PMCT, in combination with a toxicology and histology examination, can identify the cause of death to a high degree of certainty.

Background/Objective

In forensic anthropology, the biological profile is based on human variation and can help in the process of personal identification. In order to better understand shape variation of the mental region, this study analyzed the influence of population affinity and sex on the menton in adult black and white South Africans, using geometric morphometric methods (GMM).

Materials and Methods

We used cone-beam computed tomography (CBCT) scans of 291 adult dental patients with dentition patterns up to Eichner Index B3, retrospectively collected from the Oral and Dental Hospital, University of Pretoria. We placed eleven standard craniometric landmarks on the menton, mandible, and maxilla of three-dimensional (3D) reconstructions by automatic landmarking and analyzed them by applying GMM. In addition, a subtle shape matrix of seven landmarks was created for a focused analysis of the menton only. Finally, we tested the reproducibility of the landmarks placement with a dispersion analysis.

Results

The landmarks used in this study were reproducible, with an overall dispersion of less than 1 mm. Population affinity significantly influenced menton shape, with P-values = 0.001 in the complete sample and within the sex groups. Differences between sexes for these seven landmarks were also statistically significant (P-values between 0.001 to 0.003) in the complete sample, but not within population groups in isolation. The accuracy for estimation of population affinity by discriminant function analysis was 86.9%.

Conclusion

The use of automatic landmarking improved landmark reproducibility. Population affinity and sexual dimorphism significantly influenced menton shape. However, shape analysis, including all eleven landmarks, was not significantly influenced by sex. This study supports further research focusing on the facial approximations for forensic identification in South Africa.

Objective

To assess the values of the antegonial angle on panoramic radiographs and assess their role in age and sex determination.

Materials & Method

A study was carried out on 400 selected panoramic radiographs (200 males and 200 females) in the age group of 20 to 70 years. The antegonial angle was evaluated for its predictability in sex determination and age assessment. Required Statistical analysis was done.

Results

There was a significant difference in mean values of antegonial angle between males and females.

Conclusion

The antegonial region values are influenced by sex and have the potential to be used as a forensic tool in sex determination but not for age estimation.