3D reconstruction of emergency cranial computed tomography scans as a tool in clinical forensic radiology after survived blunt head trauma—Report of two cases

Diagnostic accuracies of CTs, X-rays and Lodox to detect blunt force trauma in adults, using a pig model

The accurate radiological detection of skeletal trauma is crucial for the investigation of blunt force trauma (BFT) cases. The sensitivities of CTs, X-rays and Lodox in identifying BFT fractures and minimum number of impacts in pigs, used as proxies for adult humans, were assessed. Ten human sized pig carcasses were struck with a mallet and scanned, after which the number of fractures and minimum number of impacts detected radiologically were recorded. Pig carcasses were then macerated, and the defleshed, skeletonized remains were considered the gold standard as far as number and location of fractures were concerned. CTs were most sensitive in identifying fractures and impacts in all body regions, with overall sensitivities of 55.4% and 71.5% respectively, while X-rays and Lodox had sensitivities of 25.8% and 29.3% for fractures, and 43.5% and 41.1% for impacts, respectively. All modalities were highly specific for identifying fractures (CT: 99.1%; X-ray: 98.9%; Lodox: 99.4%). CTs should be used to analyze blunt force trauma when a radiological assessment is required, but an examination of the defleshed bones remains the gold standard for the deceased whenever feasible. X-rays and Lodox have limited diagnostic value in these cases and relying on them to detect fractures may compromise the accurate forensic investigation of blunt trauma victims. However, the use of Lodox for initial screening of major trauma is still of value. Sensitivities are generally higher for detecting fractures in pigs compared to piglets, indicating that increased diagnostic value is achieved when imaging pigs compared to piglets.

The Introduction of a New Diagnostic Tool in Forensic Pathology: LiDAR Sensor for 3D Autopsy Documentation

Autopsy is a complex and unrepeatable procedure. It is essential to have the possibility of reviewing the autoptic findings, especially when it is done for medico-legal purposes. Traditional photography is not always adequate to record forensic practice since two-dimensional images could lead to distortion and misinterpretation. Three-dimensional (3D) reconstructions of autoptic findings could be a new way to document the autopsy. Besides, nowadays, smartphones and tablets equipped with a LiDAR sensor make it extremely easy to elaborate a 3D model directly in the autopsy room. Herein, a quality and trustworthiness evaluation of 3D models obtained during ten autopsies is made comparing 3D models and conventional autopsy photographic records. Three-dimensional models were realistic and accurate and allowed precise measurements. The review of the autoptic report was facilitated by the 3D model. Conclusions: The LiDAR sensor and 3D models have been demonstrated to be a valid tool to introduce some kind of reproducibility into the autoptic practice.

Assessment of the accuracy of 3D printed teeth by various 3D printers in forensic odontology

Additive manufacturing technology has benefited many sectors, and its use in forensic sciences has opened up a variety of new opportunities for analysing and exhibiting forensic materials. However, to perform analytical procedures on 3D printed bones and teeth in forensic odontology, the metric and morphological precision of the printed replicas must first be validated. To address this, the present study was undertaken using 12 extracted human teeth that were 3D printed using five different techniques. Manual measurements and a digital mesh comparison were used to evaluate the metric precision of all samples. The findings showed that the printed replicas were accurate to within 0.5 mm of the actual teeth. It was suggested that Digital Light Processing (DLP) prints be used for potential forensic odontology applications based on measurements, digital comparison, and ease of use.

Potential use of deep learning techniques for postmortem imaging

The use of postmortem computed tomography in forensic medicine, in addition to conventional autopsy, is now a standard procedure in several countries. However, the large number of cases, the large amount of data, and the lack of postmortem radiology experts have pushed researchers to develop solutions that are able to automate diagnosis by applying deep learning techniques to postmortem computed tomography images. While deep learning techniques require a good understanding of image analysis and mathematical optimization, the goal of this review was to provide to the community of postmortem radiology experts the key concepts needed to assess the potential of such techniques and how they could impact their work.

Effective approaches to three-dimensional digital reconstruction of fragmented human skeletal remains using laser surface scanning

The preservation and reconstruction of anthropological and archaeological remains has been given considerable attention in recent years, particularly within the fields of forensic science and palaeoanthropology. However, few studies have tapped the potential of using 3D technology to reconstruct, remodel and recontour remains and artefacts for the purpose of human identification. The aim of this study was to use 3D technology for the reconstruction and remodelling of fragmented and missing elements of skeletal remains. This project presents the application of three dimensional (3D) modalities to two different simulated forensic case scenarios where an attempt was made to remodel the missing element of the human cranium and reconstruction of fragmented replicated human mandible was performed. The accuracy of the reconstructed model was affirmed based on the anatomical features and digital analysis and methods for use in forensic practice are recommended.

The effect of different imaging techniques for the visualisation of evidence in court on jury comprehension

Evidence presented within a courtroom should be clear so that the members of the jury can understand it. The presentation of distressing images, such as human remains, can have a negative effect on the jury since photographic images may evoke emotional responses. Therefore, it is important to understand how other visual mediums may improve comprehension, bias, or distress individuals. For this study, 91 individuals were randomly assigned one of three visual evidence formats in a mock courtroom exercise. These included photographs, 3D visualisations, or a 3D-printed model. The results show that the use of 3D imaging improves the juror’s understanding of technical language used within a courtroom, which in turn better informs the juror’s in their decision-making.

Utility of contrast-enhanced computed tomography in forensic examination of a stab wound in living individuals

In cases of inflicted injury, the process of examining the patient for external injuries and documenting the findings is important for forensic assessment, including estimating or determining the type of weapon used and the circumstances of the violence. However, external examination is obviously limited in assessing internal injury. Here, we report the cases of two patients who survived stab wounds, where the findings of contrast-enhanced computed tomography (CT) performed for clinical diagnosis in the hospital were useful for forensic injury evaluation. In both cases, contrast-enhanced CT clearly displayed the injuries to the parenchymal organs and enabled the estimation of the direction and depth of the stab wounds by depicting the track and base of the wounds on acquired images. With the addition of the findings from examination of the external wound, the stab wounds in both victims were consistent with injury caused by the suspected weapon. Recently, imaging modalities including CT have become useful supplemental tools for precise forensic evaluation. Imaging findings obtained from these modalities could especially provide useful information for forensic assessment in clinical forensic medicine because examination of internal injury in the living body cannot generally be performed. Research on the precise diagnostic value of this method is required to utilize this method adequately in clinical forensic medicine.

A Preliminary Investigation into the Accuracy of 3D Modeling and 3D Printing in Forensic Anthropology Evidence Reconstruction

There is currently no published empirical evidence‐base demonstrating 3D printing to be an accurate and reliable tool in forensic anthropology, despite 3D printed replicas being exhibited as demonstrative evidence in court. In this study, human bones (n = 3) scanned using computed tomography were reconstructed as virtual 3D models (n = 6), and 3D printed using six commercially available printers, with osteometric data recorded at each stage. Virtual models and 3D prints were on average accurate to the source bones, with mean differences from −0.4 to 1.2 mm (−0.4% to 12.0%). Interobserver differences ranged from −5.1 to 0.7 mm (−5.3% to 0.7%). Reconstruction and modeling parameters influenced accuracy, and prints produced using selective laser sintering (SLS) were most consistently accurate. This preliminary investigation into virtual modeling and 3D printer capability provides a novel insight into the accuracy of 3D printing osteological samples and begins to establish an evidence‐base for validating 3D printed bones as demonstrative evidence.

Biomechanical behavior of brain injury caused by sticks using finite element model and Hybrid-III testing

OBJECTIVE

To study the biomechanical mechanism of head injuries beaten with sticks, which is common in the battery or assaultive cases.

METHODS

In this study, the Hybrid-III anthropomorphic test device and finite element model (FEM) of the total human model for safety (THUMS) head were used to determine the biomechanical response of head while being beaten with different sticks. Total eight Hybrid-III tests and four finite element simulations were conducted. The contact force, resultant acceleration of head center of gravity, intracranial pressure and von Mises stress were calculated to determine the different biomechanical behavior of head with beaten by different sticks.

RESULTS

In Hybrid-III tests, the stick in each group demonstrated the similar kinematic behavior under the same loading condition. The peak values of the resultant acceleration for thick iron stick group, thin iron stick group, thick wooden stick group and thin wooden stick group were 203.4 g, 221.1 g, 170.5 g and 122.2 g respectively. In finite element simulations, positive intracranial pressure was initially observed in the frontal comparing with negative intracranial pressure in the contra-coup site. Subsequently the intracranial pressure in the coup site was decreasing toward negative value while the contra-coup intracranial pressure increasing toward positive values.

CONCLUSIONS

The results illustrated that the stiffer and larger the stick was, the higher the von Mises stress, contact force and intracranial pressure were. We believed that the results in the Hybrid-III tests and THUMS head simulations for brain injury beaten with sticks could be reliable and useful for better understanding the injury mechanism.

Specific Characteristics of Injuries Inflicted by Claw Hammer

Claw hammers have the specific characteristic of having two distinct ends: one a flat head of variable form, the other bifurcated. So the use of this tool as a blunt instrument will cause varying injuries. The authors present two clinical cases of assault with a claw hammer. Examinations revealed two types of wound. A first injury composed of integumentary lacerations and underlying bone injuries in terms of "shape" suggested the use of a blunt instrument. A second injury made up of damage showing two parallel wounds or two wounds located one in the extension of the other suggested the use of an object with a bifurcated end. The combination of both types of injury should alert examiners to the possibility of the use of a claw hammer in causing the injuries in order to help direct investigators in their investigations and in the search for the weapon used.

Pediatric skull fracture diagnosis: should 3D CT reconstructions be added as routine imaging?

OBJECT

The authors compared the efficacy of combining 2D+3D CT reconstructions with standard 2D CT images in the diagnosis of linear skull fractures in children with head trauma.

METHODS

This was a retrospective evaluation of consecutive head CT studies of children presenting with head trauma. Two experienced pediatric neuroradiologists in consensus created the standard of reference. Three readers independently evaluated the 2D CT images alone and then in combination with the 3D reconstructions for the diagnosis of linear skull fractures. Sensitivity and specificity in the diagnosis of linear skull fractures utilizing 2D and 2D+3D CT in combination were measured for children less than 2 years of age and for all children for analysis by the 3 readers.

RESULTS

Included in the study were 250 consecutive CT studies of 250 patients (167 boys and 83 girls). The mean age of the children was 7.82 years (range 4 days to 17.4 years). 2D+3D CT combined had a higher sensitivity and specificity (83.9% and 97.1%, respectively) compared with 2D alone (78.2% and 92.8%, respectively) with statistical significance for specificity (p < 0.05) in children less than 2 years of age. 2D+3D CT combined had a higher sensitivity and specificity (81.3% and 90.5%, respectively) compared with 2D alone (74.5% and 89.1%, respectively) with statistical significance for sensitivity (p < 0.05) in all children.

CONCLUSIONS

In this study, 2D+3D CT in combination showed increased sensitivity in the diagnosis of linear skull fractures in all children and increased specificity in children less than 2 years of age. In children less than 2 years of age, added confidence in the interpretation of fractures by distinguishing them from sutures may have a significant implication in the setting of nonaccidental trauma. Furthermore, 3D CT is available at no added cost, scan time, or radiation exposure, providing trainees and clinicians with limited experience an additional valuable tool for routine imaging of pediatric head trauma.

Imaging for homicide investigations

The authors present the opportunities of the application of post-mortem imaging, focusing on post-mortem computed tomography and post-mortem computed tomography angiography in modern forensic investigation of homicide cases. The paper is based on scientific publications related to the subject from ca. the past 10 years, supplemented by the authors' own experiences. The article is illustrated with reconstructions based on the authors' own cases related to homicide due to ballistic/sharp/blunt trauma. As is shown, the results of evaluation of post-mortem computed tomography allow better diagnosis, documentation and visualisation of forensic examinations.

Consent to forensic radiologic examinations by living crime victims

The purpose of this prospective study was to evaluate whether people approve radiological examinations specifically for the documentation of findings for the use in criminal proceedings. Forty two crime victims and 42 controls without a history of sustained violence were asked via telephone interview whether they would agree to forensic radiological examinations and if radiation exposure and the duration of the examination were factors influencing their consent. The consent to specifically forensic radiological examinations was high in both groups, however, higher in victims than in controls (85-96% compared to 64-77%, respectively, depending on the imaging modality). All of the victims and 93% of the controls consented to at least one of the proposed imaging modalities, i.e. X-ray, computed tomography and magnetic resonance imaging. Most of the interviewees did not consider the duration of the examination to be relevant to their consent (79% of the crime victims and 93% of the controls); however, the radiation exposure associated with the examination was relevant for 55% of the controls but only for 19% of the victims. These results show that there is a great consent to the application of radiological methods for forensic purposes. This is important for the growing field of forensic radiology as the approval of the examination by the victim is a legal prerequisite.

Skin injury model classification based on shape vector analysis

Background: Skin injuries can be crucial in judicial decision making. Forensic experts base their classification on subjective opinions. This study investigates whether known classes of simulated skin injuries are correctly classified statistically based on 3D surface models and derived numerical shape descriptors.

Methods: Skin injury surface characteristics are simulated with plasticine. Six injury classes – abrasions, incised wounds, gunshot entry wounds, smooth and textured strangulation marks as well as patterned injuries - with 18 instances each are used for a k-fold cross validation with six partitions. Deformed plasticine models are captured with a 3D surface scanner. Mean curvature is estimated for each polygon surface vertex. Subsequently, distance distributions and derived aspect ratios, convex hulls, concentric spheres, hyperbolic points and Fourier transforms are used to generate 1284-dimensional shape vectors. Subsequent descriptor reduction maximizing SNR (signal-to-noise ratio) result in an average of 41 descriptors (varying across k-folds). With non-normal multivariate distribution of heteroskedastic data, requirements for LDA (linear discriminant analysis) are not met. Thus, shrinkage parameters of RDA (regularized discriminant analysis) are optimized yielding a best performance with λ = 0.99 and γ = 0.001.

Results: Receiver Operating Characteristic of a descriptive RDA yields an ideal Area Under the Curve of 1.0for all six categories. Predictive RDA results in an average CRR (correct recognition rate) of 97,22% under a 6 partition k-fold. Adding uniform noise within the range of one standard deviation degrades the average CRR to 71,3%.

Conclusions: Digitized 3D surface shape data can be used to automatically classify idealized shape models of simulated skin injuries. Deriving some well established descriptors such as histograms, saddle shape of hyperbolic points or convex hulls with subsequent reduction of dimensionality while maximizing SNR seem to work well for the data at hand, as predictive RDA results in CRR of 97,22%. Objective basis for discrimination of non-overlapping hypotheses or categories are a major issue in medicolegal skin injury analysis and that is where this method appears to be strong. Technical surface quality is important in that adding noise clearly degrades CRR.

Trial registration: This study does not cover the results of a controlled health care intervention as only plasticine was used. Thus, there was no trial registration.

Weapon identification using antemortem computed tomography with virtual 3D and rapid prototype modeling--a report in a case of blunt force head injury

A frequent request of a prosecutor referring to forensic autopsy is to determine the mechanism of an injury and to identify the weapons used to cause those injuries. This task could be problematic in many ways, including changes in the primary injury caused by medical intervention and the process of healing. To accomplish this task, the forensic pathologist has to gather all possible information during the post-mortem examination. The more data is collected, the easier it is to obtain an accurate answer to the prosecutor's question. The authors present a case of head injuries that the victim sustained under unknown circumstances. The patient underwent neurosurgical treatment which resulted in alteration of the bone fracture pattern. The only way to evaluate this injury was to analyze antemortem clinical data, especially CT scans, with virtual 3D reconstruction of the fractured skull. A physical model of a part of the broken skull was created with the use of 3D printing. These advanced techniques, applied for the first time in Poland for forensic purposes, allowed investigators to extract enough data to develop a hypothesis about the mechanism of injury and the weapon most likely used.