Lars Uhrenholt

An alternative approach to Computerized Tomography (CT) in forensic pathology

Computerized Tomography (CT) is used by some forensic pathology departments as a supplement to the forensic autopsy. Departments with a limited number of autopsies may find it relatively expensive to acquire and operate a CT-scanner. Furthermore, it requires a great deal of training and experience to interpret the radiological data. We are currently evaluating CT in order to decide whether the benefits match the efforts. In selected death-investigations the Department of Radiology at Aarhus University Hospital performs CT of the body on behalf of the Institute of Forensic Medicine at Aarhus University and a skilled radiologist interprets the data. We present our radiological findings in the 20 cases where we have used CT and compare them to the autopsy findings. The cases include fatalities from beatings, stabbings, gunshots, fires and traffic accidents. CT is an excellent tool for documenting and illustrating certain lesions, such as gunshot wounds and bone fractures, where we can obtain information that possibly would have been missed at the autopsy. We believe, however, that further research is required before we can recommend CT as a part of a standard forensic autopsy. The cooperation between forensic and radiological departments is a good approach for smaller forensic departments that insures a skilled interpretation without having to divert a lot of resources to equipment and training.

Inside out: modern imaging techniques to reveal animal anatomy.

Animal anatomy has traditionally relied on detailed dissections to produce anatomical illustrations, but modern imaging modalities, such as MRI and CT, now represent an enormous resource that allows for fast non-invasive visualizations of animal anatomy in living animals. These modalities also allow for creation of three-dimensional representations that can be of considerable value in the dissemination of anatomical studies. In this methodological review, we present our experiences using MRI, CT and μCT to create advanced representation of animal anatomy, including bones, inner organs and blood vessels in a variety of animals, including fish, amphibians, reptiles, mammals, and spiders. The images have a similar quality to most traditional anatomical drawings and are presented together with interactive movies of the anatomical structures, where the object can be viewed from different angles. Given that clinical scanners found in the majority of larger hospitals are fully suitable for these purposes, we encourage biologists to take advantage of these imaging techniques in creation of three-dimensional graphical representations of internal structures.

Degenerative and traumatic changes in the lower cervical spine facet joints

Objective: The aim of this study was to examine anatomical variables of the lower cervical spine facet joints with regard to age, gender, and exposure to trauma. Methods: The lower four cervical spine segments (C4–C7 included) were obtained from 40 subjects during autopsy: 12 females and 28 males (median age 35 years, range 20–49). Through an available 636 unique facets (318 joints), 1830 randomly obtained observation lines were defined. Each of these lines resembled a 3‐mm‐thick parasaggital slice through a facet from which 10‐µm‐thick histological sections were produced and evaluated microscopically. Inter‐ and intraobserver agreement was tested on four randomly selected facets from each subject. Results: Significant age‐, gender‐, and trauma‐related changes in the bone, cartilage, and soft tissues were observed, including subchondral sclerosis, fibrillation and splitting of cartilage, and cartilage length differences. Females were less affected by changes in the cartilage than males. Two synovial folds were present in all but one joint. Moderate interobserver and good intraobserver agreement were achieved. Conclusions: This study provides knowledge of the anatomy of the cervical spine facet joints. The findings support existing knowledge that males are more commonly affected by degenerative changes than females and that these changes are common from a young age. Histomorphometry confirms the presence of synovial folds in all of the facet joints. Following spinal trauma, pathological lesions may be produced in the facet joints and/or accentuate already existing pathology. The information provided in this study may have relevance for patients with neck pain.

High-resolution ex vivo magnetic resonance angiography: a feasibility study on biological and medical tissues

BackgroundIn biomedical sciences, ex vivo angiography is a practical mean to elucidate vascular structures three-dimensionally with simultaneous estimation of intravascular volume. The objectives of this study were to develop a magnetic resonance (MR) method for ex vivo angiography and to compare the findings with computed tomography (CT). To demonstrate the usefulness of this method, examples are provided from four different tissues and species: the human placenta, a rice field eel, a porcine heart and a turtle.ResultsThe optimal solution for ex vivo MR angiography (MRA) was a compound containing gelatine (0.05 g/mL), the CT contrast agent barium sulphate (0.43 mol/L) and the MR contrast agent gadoteric acid (2.5 mmol/L). It was possible to perform angiography on all specimens. We found that ex vivo MRA could only be performed on fresh tissue because formalin fixation makes the blood vessels permeable to the MR contrast agent.ConclusionsEx vivo MRA provides high-resolution images of fresh tissue and delineates fine structures that we were unable to visualise by CT. We found that MRA provided detailed information similar to or better than conventional CTA in its ability to visualize vessel configuration while avoiding interfering signals from adjacent bones. Interestingly, we found that vascular tissue becomes leaky when formalin-fixed, leading to increased permeability and extravascular leakage of MR contrast agent.

Pathoanatomy of the lower cervical spine facet joints in motor vehicle crash fatalities

Non-lethal injuries to the cervical spine facet joints have previously been described in decedents from motor vehicle crashes and in clinical settings these joints have been identified as potential culprits in chronic neck pain syndromes. The aim of this study was to conduct a detailed examination of the lower cervical spine facet joints in a forensic cohort of motor vehicle crash victims and controls using comparable data from medicolegal autopsy, stereomicroscopy and histological evaluations. Injuries to the cervical spine facet joints were common in the trauma cases and included facet fractures, haemarthrosis, and disruption and bleeding in the synovial folds. The injuries could not be reliably verified on stereomicroscopic evaluation, and routine autopsy procedures did not reveal any of the injuries to the facet joints. Despite the presence of these pathoanatomical lesions in road traffic crash fatalities their prevalence and potential clinical implications in survivors from motor vehicle crashes is unknown.

Imaging Occult Lesions in the Cervical Spine Facet Joints

Discrete injuries in the lower cervical spine facet joints have been reported in studies of motor vehicle crash victims. We conducted a detailed investigation of these joints from 20 motor vehicle crash fatalities and 22 decedents due to nontraumatic causes, using conventional radiology, computed tomography, and magnetic resonance imaging to examine whether the diagnostic imaging procedures could identify injuries in the facet joints. The diagnostic imaging procedures identified facet joint fractures in 4 of the 19 trauma cases with computed tomography having the highest sensitivity and obtaining good correlation with findings from the microscopical evaluation. No diagnostic imaging procedure could reliably evaluate the integrity of the synovial folds or the joint spaces for bleeding despite microscopical evidence of such findings in these structures in a large proportion of the motor vehicle crash fatalities. This study emphasizes the need for scientific evidence of validity and reliability of advanced diagnostic imaging procedures in forensic settings, in particular, with regard to occult soft tissue lesions, and cautions uncritical use of negative results from these procedures until such evidence has been produced.

Contributions from Forensic Imaging to the Investigation of Upper Cervical Fractures

Abstract:  Injuries to the upper cervical spine (UCS) are common in traumatic deaths and postmortem computed tomography (PMCT) may contribute to the forensic investigation. This study presents PMCT in comparison with autopsy in the examination of UCS injury. Thirteen consecutive cases with UCS fracture and/or cranio‐cervical dislocation were examined with PMCT and autopsy, and the findings were correlated. Neither of the techniques identified all UCS injuries. Fractures of atlas and axis were best visualized with PMCT whereas cranio‐cervical dislocation was better identified during autopsy. Serious injuries were present after both high‐ and low‐energy trauma. Medico‐legal autopsy in combination with PMCT produced a thorough evaluation of UCS injuries. By combining these procedures detailed investigations, including accident reconstruction and injury pattern analysis, can be performed. This study supports the routine application of PMCT, as a supplement to the medico‐legal autopsy of deaths with UCS injuries.

Esophageal injury in fatal rear-impact collisions

Neck injuries resulting from motor vehicle collisions (MVC), often referred to as whiplash trauma and injury, often demonstrate little or no evidence of significant tissue damage. In rare instances, however, serious injury to the anterior neck organ injuries can result from such trauma. The present study describes esophageal injury associated with rear-impact collisions, based on a unique case report, review of the scientific literature and a query in the National Automotive Sampling System (NASS) database of the US National Highway Traffic Safety Administration. The Medline search and present case study totaled five cases of rear-impact collision-related serious esophageal injury (laceration or rupture). In the four published cases all patients survived, whereas in the presented case study, the patient died due to mediastinitis and sepsis. The NASS query revealed an additional three cases out of a total of 55,926 investigated crashes. All three cases were associated with fatalities. Although no anatomical or bioengineering studies have presented data on the behavior of the esophagus during rear-impact whiplash loading, sudden tensile and/or compressive forces is the likely explanation of injury, often in combination with a local fracture of a vertebral body. In these 8 cases significant esophageal injury carried a substantial (50%) risk of mortality. Clinicians should be aware of the potential for significant complications in the whiplash trauma-exposed patient who complains of chest pain, mid-thoracic pain, discomfort in the neck and throat, respiratory distress, or hoarseness. For those forensic specialists involved in whiplash cases these study results highlight the need to consider esophageal injuries as a rare but potential consequence of whiplash trauma.

Investigation of a fatal airplane crash: autopsy, computed tomography, and injury pattern analysis used to determine who was steering the plane at the time of the accident. A case report.

A fatal accident is reported in which a small single-engine light airplane crashed. The airplane carried two persons in the front seats, both of whom possessed valid pilot certificates. Both victims were subject to autopsy, including post-mortem computed tomography scanning (PMCT) prior to the autopsy. The autopsies showed massive destruction to the bodies of the two victims but did not identify any signs of acute or chronic medical conditions that could explain loss of control of the airplane. PMCT, histological examination, and forensic chemical analysis also failed to identify an explanation for the crash. A detailed review of an airplane identical to the crashed airplane was performed in collaboration with the Danish Accident Investigation Board and the Danish National Police, National Centre of Forensic Services. The injuries were described using the abbreviated injury scale, the injury severity score, 3-dimensional reconstructions of the PMCT, and an injury pattern analysis. We describe how, on basis of these data, we reached a conclusion about which of the two victims was the most likely to have been in control of the airplane at the time of accident. Furthermore, we argue that all victims of fatal airplane crashes should be subject to forensic autopsy, including PMCT and forensic chemical analysis. The continuous accumulation of knowledge about injury patterns from “simple” accidents is the foundation for the correct analysis of “difficult” accidents.

Serious head and neck injury as a predictor of occupant position in fatal rollover crashes

Serious head and neck injuries are a common finding in fatalities associated with rollover crashes. In some fatal rollover crashes, particularly when ejection occurs, the determination of which occupant was driving at the time of the crash may be uncertain. In the present investigation, we describe the analysis of rollover crash data from the National Automotive Sampling System-Crashworthiness Data System for the years 1997 through 2007 in which we examined the relationship between a serious head and neck injury in an occupant and a specified degree of roof deformation at the occupants seating position. We found 960 occupants who qualified for the analysis, with 142 deaths among the subjects. Using a ranked composite head and neck injury score (the HNISS) we found a strong relationship between HNISS and the degree of roof crush. As a result of the analysis, we arrived at a predictive model, in which each additional unit increase in HNISS equated to an increased odds of roof crush as follows: for ≥8 cm of roof crush compared with <8 cm by 4%, for ≥15 cm of roof crush compared to <8 cm by 6% and for ≥30 cm of roof crush compared to <8 cm by 11%. We describe two hypothetical scenarios in which the model could be applied to the real world investigation of occupant position in a rollover crash-related fatality.