Estimating Biological Characteristics With Virtual Laser Data

Laser scanning technology is increasingly being used in forensic anthropological research to obtain virtual data for archival purposes and post hoc measurement collection. This research compared the measurement accuracy of two laser scanners—the FARO Focus^3D 330X and the FARO Freestyle^3D—against traditionally obtained (i.e., by hand) control data (N = 454). Skeletal data were collected to address a novel question: the ability of laser scanning technology to produce measurements useful for biological characteristic estimation, such as sex and stature. Results indicate that both devices produced measurements very similar to control (c. 3‐mm average absolute error), but also illuminate a tendency to under‐measure. Despite these findings, the virtual data produced sex and stature estimates that varied little from control‐produced estimates, signifying the usefulness of virtual data for preliminary biological identification when the skeletal elements are no longer available for physical analysis.     

The Frontal Sinus Cavity Exhibits Sexual Dimorphism in 3D Cone‐beam CT Images and can be Used for Sex Determination

Few studies have assessed the use of the frontal sinus cavities for sex differentiation. In this study, a new methodology was used to assess the reliability of CBCT images of the frontal sinus cavity for determining sex based on the sexual dimorphism found in this anatomical structure. The survey sample consisted of 130 scans that were reconstructed three‐dimensionally. 3D images of the cavity volume in the frontal, lateral, and basal views were exported in TIFF. The following variables were measured in a second program: area, perimeter, bounding rectangle, ellipse fit, circularity, aspect ratio, roundness, solidity, and Feret's diameter. The methodology demonstrated the existence of sexual dimorphism with an accuracy of 80.0% in the logistic regression model. The basal view had the greatest explanatory power in the final model. This methodology may be used as an alternative way of determining a reliable biological profile during the analysis of skeletal remains.     

Validation of the New Interpretation of Gerasimov's Nasal Projection Method for Forensic Facial Approximation Using CT Data,

The most common method to predict nasal projection for forensic facial approximation is Gerasimov's two‐tangent method. Ullrich H, Stephan CN (J Forensic Sci, 2011; 56: 470) argued that the method has not being properly implemented and a revised interpretation was proposed. The aim of this study was to compare the accuracy of both versions using a sample of 66 postmortem cranial CT data. The true nasal tip was defined using pronasale and nasal spine line, as it was not originally specified by Gerasimov. The original guidelines were found to be highly inaccurate with the position of the nasal tip being overestimated by c. 2 cm. Despite the revised interpretation consistently resulting in smaller distance from true nasal tip, the method was not statistically accurate (p > 0.05) in positioning the tip of the nose (absolute distance >5 mm). These results support that Gerasimov's method was not properly performed, and Ullrich H, Stephan CN (J Forensic Sci, 2011; 56: 470) interpretation should be used instead.     

Comparative Evaluation of Potentially Radiolucent Projectile Components by Radiographs and Computed Tomography

Projectile components that are traditionally radiolucent can be of considerable importance in determination of weapon type and caliber, but they are often missed on evaluation of postmortem radiographs. We hypothesized that these components would be significantly better visualized by evaluation of computed tomography (CT) scans compared to the practice standard of radiography alone. In this project, potentially radiolucent projectile components were both pulled apart and fired, and the radiolucent components were recovered. These components were embedded in blocks of ballistics gelatin and were imaged using both radiography and CT. The scans were evaluated by three blinded, board‐certified radiologists for the presence/absence of projectile components and true‐negative regions in each block. If a radiologist indicated visualization of a projectile component, they were further requested to describe their observation. It was found that traditionally radiolucent projectile components are not significantly more often identified on CT scans than radiography (p < 0.05).     

Age at Death Estimation Using Multislice Computed Tomography Reconstructions of the Posterior Pelvis*

Abstract: Thanks to recent advances, computed tomography is now seen as a tool of great value in the field of physical anthropology. In this study, we focused on the posterior pelvis and the auricular surface and evaluated the accuracy of 3D reconstructions of the auricular surface, using a methodology derived from a previous study by Lovejoy et al. We also looked for trabecular bone criteria expressing age‐related changes. Forty‐six coxal bones were scanned, and scoring of macroscopic criteria showed a good agreement between 3D reconstructions and photographs, especially for transverse organization (k = 0.90). The changes occurring in the posterior part of the sacropubic trabecular bundle were evaluated on CT reconstructions via three new criteria, which exhibited a good intra‐ and inter‐observer agreement (k = 0.77–0.89), and were particularly useful in identifying older subjects. We concluded that these CT‐evaluated trabecular bone criteria are promising and yield useful information about age at death.     

Virtual autopsy and forensic anthropology of a mummified fetus: a report of one case

A jar containing the mummified body of a fetus was found in a bush near a building. Full-body multislice computed tomography (MSCT) was performed prior to autopsy to study the bones and internal organs. Age was estimated by measuring femoral and tibial lengths and examining the temporal and occipital bones. The results were then compared with the autopsy and histopathological findings. MSCT was superior to autopsy for examination of the bones and internal organs. Autopsy was difficult because of the fragility of the dried corpse. MSCT determined the gestational age of the fetus and excluded skeletal abnormalities. Estimated age was similar with the two methods used. However, the major advantage of MSCT was rapid measurement of bones or anatomical regions which are difficult to examine during autopsy and which required specific preparation for further anthropological study. This case report illustrates the possibilities offered by MSCT for studying mummified bodies, even fetuses.     

Whole body postmortem angiography with a high viscosity contrast agent solution using poly ethylene glycol as contrast agent dissolver

Postmortem minimal invasive angiography has already been implemented to support virtual autopsy examinations. An experimental approach in a porcine model to overcome an initially described artificial tissue edema artifact by using a poly ethylene glycol (PEG) containing contrast agent solution showed promising results. The present publication describes the first application of PEG in a whole corpse angiographic CT examination. A minimal invasive postmortem CT angiography was performed in a human corpse utilizing the high viscosity contrast agent solution containing 65% of PEG. Injection was carried out via the femoral artery into the aortic root in simulated cardiac output conditions. Subsequent CT scanning delivered the 3D volume data of the whole corpse. Visualization of the human arterial anatomy was excellent and the contrast agent distribution was generally limited to the arterial system as intended. As exceptions an enhancement of the brain, the left ventricular myocardium and the renal cortex became obvious. This most likely represented the stage of centralization of the blood circulation at the time of death with dilatation of the precapillary arterioles within these tissues. Especially for the brain this resulted in a distinctively improved visualization of the intracerebral structures by CT. However, the general tissue edema artifact of postmortem minimal invasive angiography examinations could be distinctively reduced.     

外伤性视神经萎缩光相干断层成像表现及视功能损害

目的分析单侧外伤性视神经萎缩的光相干断层成像（optical coherence tomography,OCT）表现并探求其与视力、视野损害的关系。方法对15例外伤性视神经萎缩的法医学鉴定案例进行研究,所有案例均进行眼科常规检查、视觉电生理检查及视盘OCT检查,视力大于0．1者进行视野检查。结果15例视神经损伤者均有不同程度的视力、视野等视功能损害及视盘视网膜神经纤维层萎缩。结论外伤性视神经萎缩多始自视盘颞侧,鼻侧萎缩发生最晚且最轻;视神经萎缩程度越重,相应的视功能损害也越重;OCT技术对评价视神经萎缩有重要的意义,与视功能损害也有较好的吻合性。     

CT技术在尸体检验中的应用

自1990年CT首次应用于死后尸体检验以来,不断有学者对其在全身尸体检验中的价值和优势进行探讨。CT用于解剖前的系统检验,对解剖有指导作用,可以与解剖所见互相印证,有时还能弥补解剖检验的不足。本文综述了CT技术在尸体检验中对死因分析、致伤方式推断和个体识别等方面的主要应用价值及其发展趋势,提示CT技术与其他学科联合应用将在法医病理学领域发挥更大的作用。     

Initial Study for the Determination of the Sequence of Intersecting Lines between Gel Pens and Seals by Optical Coherence Tomography*

Determining the sequence of intersecting lines is a significant issue in the forensic document examination that can reveal the fraud or distinguish between different allegations. Optical coherence tomography (OCT) is a high-resolution cross-sectional imaging technique that has been introduced into forensic science field recently. The potential of OCT as a novel method to determine the sequence of intersecting lines was examined for the first time. In this study, a spectral-domain OCT system with a center wavelength of 900 nm was employed to perform nondestructive examination on determining the sequence of 18 heterogeneous intersecting line samples produced using three types of gel pens and three brands of stamp pad ink seals. Two-dimensional (2D) cross-sectional, and three-dimensional (3D) volumetric images of the intersecting lines were obtained by the OCT system. Several features were noted and analyzed to successfully determine the sequence of all the 18 samples. Blind tests were also conducted to demonstrate the effectiveness of OCT technique. The results illustrate that OCT technology can provide an effective and accurate method for sequencing intersecting lines of gel pen ink and seal ink, which may complement the conventional methods used in the examination of questioned documents.