Forensic Imaging最新文献

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.

Objectives

variations in the positions of organs and bones resulting from two different body positions during PMCT were investigated.

Methodology

Forty-four bodies were CT-scanned in two positions and compared using 18 landmarks and 27 distances.

Results and conclusion

Differences below 1 cm were observed for all measurements. The most significant variation was observed along the cranio-caudal plan (z). Awareness of these movements is important when using 3D models for visualization or 3D reconstructions.

Filtering is known to improve image quality of CT scans. Water immersion is one type of filtering that has been used for CT scanning dry (skeletonized) bones, and it has been suggested that this approach can increase measurement accuracy and improve fracture resolution. These tests have previously involved clinical CT scanners. Here we use an industrial micro-CT scanner and test whether water immersion and other x-ray filtering options increases fracture resolution in reconstructed scans of dry bones.

Eleven dry non-human bones were CT scanned using the same acquisition parameters, while varying filter options. Bones were scanned (1) in an unfiltered “dry” air environment, (2) using metal filters at the x-ray source, and (3) with the bones immersed in water. A small subset of bones (N = 3) was also scanned using the same parameters except increasing the number of projections acquired from 500 to 1500. Reconstructed scans were evaluated by the authors, in part using a Likert scale comparing filtered with unfiltered scans, to assess fracture resolution (overall appearance and extent).

Results showed that increasing the projections resulted in the greatest improvement in fracture resolution, followed by filtering at the x-ray source. Water immersion performed poorly overall, possibly due to movement artifacts that result from this type of scanning, in which the specimen rotates on a stage during the scan. When using this type of CT scanner, if increased fracture resolution is desired, water immersion is not recommended; increasing the number of projections or filtering at the x-ray source is suggested instead.

Objectives

In quantitative postmortem computed tomography (qPMCT) the presence of putrefaction gas in tissues can obscure measurements such as bone mineral density (BMD). Quantitative CT analysis procedures adopted directly from clinical CT may not be designed to compensate for intracorporeal gas, which require additional measures for PM-imaging applications. Thus, a solid unbiased procedure for volumetric BMD analysis in PMCT of the deceased presenting with intracorporeal gas is desirable.

Materials and methods

We tested three different analysis procedures (AP1-3) for BMD analysis of the lumbar vertebrae (L1-3). Data in this retrospective study was based on synchronous PMCT acquisition with a solid five-phase Cann-Genant phantom from routine forensic examinations of 154 individuals distributed into three putrefaction groups: “None” (n = 95), “Mild” (n = 54), and “Moderate” (n = 10). AP1 was based on commercially available software (“Mindways”), which required the operator to subjectively place region of interest (ROIs) in areas without gas. The open-source software (“FIJI”) was used for AP2 and AP3 and enabled comparison of objectively placed ROIs with AP1. In AP3, threshold-filtering was applied to remove the signal from gas (in AP2 data) prior to BMD analysis.

Results

AP1 provided higher BMD values than AP2-3 due to subjective placement of ROIs in denser cortical areas. AP2 yielded the lowest BMD measurements with most variation, while AP3 yielded BMD measurements comparable to in vivo values published in clinical studies. AP3 provided greater interobserver correlation.

Conclusion

AP3 provided a simple open-source software-based approach to PMCT BMD analysis that allows for precise BMD measurements in PMCT.

Objectives

Injuries caused by animal abuse are termed non-accidental injuries, and should be distinguished from accidental injuries. We compared postmortem computed tomography (PMCT) and necropsy findings in deceased cat bodies suspected of having been abused to determine whether findings previously reported to be associated with abuse or accident could be ascertained by necropsy or PMCT.

Materials and methods

Seven deceased cat bodies requested by the police for necropsy because of suspicion of animal abuse were used to compare necropsy and PMCT findings.

Results

PMCT revealed gas distribution abnormalities, such as pneumocephalus and pneumothorax, and bone lesions findings, such as cervical and pelvic fracture; however, several of these were not confirmed at necropsy. Findings such as liver contusion and injury to the posterior vena cava were confirmed only by necropsy and not by PMCT. Findings related to animal abuse, i.e., ocular injuries, skull, bilateral rib, and femoral fractures were confirmed by both PMCT and necropsy in 3, 5, 2, and 2 cats, respectively. Pneumothorax, pelvic fracture, and sacroiliac luxation, related to accidents, were confirmed only by CT in 6 of 6, 1 of 4, and 2 of 2 bodies.

Conclusion

PMCT revealed gas- and some bone-related findings more efficiently than necropsy, and a combination of PMCT and necropsy is recommended to perform, particularly if the death circumstances is unknown.

Human identification forms an integral part of forensic and biological anthropology. For proper identification, a biological profile made up of biodata such as age, sex, ancestry, antemortem stature, and factors of individualization, is obtained and stored for use by anthropologists. A correct sex estimation can help unravel other anthropological parameters. South Africa has a multi-dimensionally high crime rate and its largest distinct population group (Black South Africans) is most affected by such crimes. Several authors have in the past used cranial measurements to carry out sex discrimination among South Africans, such attempts have largely been done using direct assessment of post-mortem specimens and on subjects of European Descent. This study, therefore, attempted to overcome these drawbacks by using a non-invasive method, the three-dimensional computed tomography (3DCT) to obtain population-specific data from a contemporary Black South African population group. It obtained measurements from cranial CT records of 350 Black South Africans (50 % sex ratio) housed in the Radiology Department of Charlotte Maxeke Johannesburg Academic Hospital. The Xiris and IntelliSpace software were used to reconstruct the images into three-dimensional forms from which measurements were taken. Evaluation of previously derived equations using data from the current study yielded low average classification accuracies which necessitated the formulation of new equations. Discriminant function analysis yielded acceptably high average classification accuracies for sex estimation which ranged from 78.3 % to 82.9 %.

The diagnostic assessment of sudden and unexpected cardiovascular deaths remains intricate in forensic medicine. Building upon the foundational technique introduced by P. Fais et al.(2018), we present modifications to the post-mortem infrared coronary angiography (PIC) tailored specifically for the assessment of human hearts. Refinements to PIC encompass the integration of a 3D-printed clamp for catheter stabilization and the procedural alteration of utilizing warm water injections, negating the need for additional cardiac cooling. An enhanced imaging modality is achieved using the FLIR Thermal Lepton 3.5 camera, embedded within the robust Cat S62 Pro mobile device, ensuring optimal resolution and suitability for an autopsy environment. The advanced PIC technique provides superior visualization of the coronary arteries, frequently correlating with subsequent autopsy and histological assessments. Notably, the method allows immediate continuation to the autopsy without compromising the cardiac structure. Nevertheless, certain anatomical variances, such as muscular bridging or pronounced pericardial fat, might reduce locally what appears to be an otherwise excellent specificity. The refined PIC method emerges as a pivotal diagnostic adjunct in forensic evaluations of sudden cardiovascular fatalities. Its ability to preserve cardiac integrity and facilitate uninterrupted autopsy progression underscores its potential utility. However, rigorous validation is imperative to ascertain its comprehensive applicability and inherent limitations.

Introduction

Post-mortem CT data files can be used to create curved multi-planar dental reconstructions for use in the identification of the deceased.

Materials and methods

21 decedents were scanned using a Siemens Somatom Definition Flash CT scanner on admission to VIFM. This data was reconstructed into four differing dental CMPRS on both the CT Console workstation and the Syngo.Via workstation. Cases selected met the following criteria: requiring scientific identification and adult dentition present. The four reconstruction techniques on two post processing platforms were then compared and graded by a forensic odontologist.

Results

For both maxilla and mandible data sets the CT Console 2.5/2.5 faired poorer than all the other reconstructions included in this study. Statistically speaking all the other reconstruction techniques were of equivalent value. The reconstruction that was graded as best for AM: PM comparison most frequently was 20 mm/5 mm for both jaws.

Discussion

The SyngoVia® software's capacity to correct for head rotation and tilt can virtually align the image to a more symmetrical position. Used in combination with the thicker reconstruction slices of 20 mm combined with finer slice interval of 5 mm offers the image appearance similar to that of a true AM OPG projection and can enhance the features useful for dental identification comparison techniques.

Conclusion

The 20 mm slice thickness/5 mm slice interval reconstruction method (processed on the SyngoVia® platform) provides the most useful image for AM to PM dental comparisons.

In Denmark, post-mortem CT scanning (PMCT) was introduced over 20 years ago. The Department of Forensic Medicine, University of Copenhagen, implemented whole-body CT scanning before each autopsy in December 2002, followed by the Department at University of Southern Denmark in Odense in 2006 and at the University of Aarhus 2008. Subsequently, other equipment, including Magnetic Resonance (MR) scanners, surface scanners, photogrammetry equipment and 3D printers, were introduced in the following years. In this review, we will provide contemporary insights into the status of forensic imaging in Denmark, including requisitioned work and research. We will also discuss future directions in the field.

X-ray analysis of individuals who have died due to unnatural causes is important for the detection of potential skeletal pathologies, injuries, and foreign objects, which assists in the determination of the cause of death, recovery of evidence, and identification of the deceased. At the Johannesburg Forensic Pathology Services medico-legal mortuary (South Africa), the LODOX Statscan is used due to the system's capability to rapidly produce a full-human-body, high-quality digital image. This study aimed to provide an overview of which cases were selectively x-rayed using the LODOX Statscan at this facility. This was a retrospective mortuary case file review, which highlighted the frequency and reasons for x-ray usage over a four-year period (2016–2019) and described the demographics, circumstances of death and cause of death in x-rayed cases over a two-year period (2018 and 2019). A total of 2026 cases (15.28% of all cases received) were x-rayed over the 2016-2019 period. The purposes for selectively x-raying cases were to assist the autopsy (n=1735), identification (n=228), forensic anthropological analysis (n=34) and research (n=29). the most common circumstance and cause of death in the x-rayed cases was due to gunshot wounds (80% & 85% respectively). This study highlighted the benefits and limitations of low-dosage X-ray digital scans in a facility that is exemplary of many facilities in developing countries where the case numbers are significantly high, manpower is limited, and the lack of funding and infrastructure precludes the use of other modalities commonly used in developed countries, especially were gunshot wound cases are frequent.