Pros and cons of low-field magnetic resonance imaging in veterinary practice

Low-field (LF) (0.2-0.4T) magnetic resonance (MR) imaging predominates in veterinary practice. Advantages of LF MR include reduced costs, better patient access, and greater safety. High quality examinations can be achieved using appropriate protocols and investing more scanning time than with high-field (HF) systems. The main disadvantage of LF MR is the reduced signal to noise ratio compared with HF systems. LF MR protocols for small animal brain and spine imaging are described.

Forensic veterinary radiology: ballistic-radiological 3D computertomographic reconstruction of an illegal lynx shooting in Switzerland

The lynx, which was reintroduced to Switzerland after being exterminated at the beginning of the 20th century, is protected by Swiss law. However, poaching occurs from time to time, which makes criminal investigations necessary. In the presented case, an illegally shot lynx was examined by conventional plane radiography and three-dimensional multislice computertomography (3D MSCT), of which the latter yielded superior results with respect to documentation and reconstruction of the inflicted gunshot wounds. We believe that 3D MSCT, already described in human forensic-pathological cases, is also a suitable and promising new technique for veterinary pathology.

Gas embolism following intraosseous medication application proven by post-mortem multislice computed tomography and autopsy

The post-mortem use of modern imaging techniques such as multislice computed tomography (MSCT) is becoming increasingly important as an aid for conventional autopsy. This article presents a case of a 4-month-old boy who died from sudden infant death syndrome (SIDS) with intravascular gas after an intraosseus medication application documented by post-mortem MSCT. It is most likely that the gas entered the body during resuscitation. This case emphasises the advantage of post-mortem imaging as a complementary aid for the autopsy. We conclude that during emergency treatment, the medical staff should be aware of the possibility of causing a gas embolism following intraosseus medication. Resuscitation with an inserted, disconnected intraosseous needle should be avoided.

VIRTOPSY: minimally invasive, imaging-guided virtual autopsy

Invasive "body-opening" autopsy represents the traditional means of postmortem investigation in humans. However, modern cross-sectional imaging techniques can supplement and may even partially replace traditional autopsy. Computed tomography (CT) is the imaging modality of choice for two- and three-dimensional documentation and analysis of autopsy findings including fracture systems, pathologic gas collections (eg, air embolism, subcutaneous emphysema after trauma, hyperbaric trauma, decomposition effects), and gross tissue injury. Various postprocessing techniques can provide strong forensic evidence for use in legal proceedings. Magnetic resonance (MR) imaging has had a greater impact in demonstrating soft-tissue injury, organ trauma, and nontraumatic conditions. However, the differences in morphologic features and signal intensity characteristics seen at antemortem versus postmortem MR imaging have not yet been studied systematically. The documentation and analysis of postmortem findings with CT and MR imaging and postprocessing techniques ("virtopsy") is investigator independent, objective, and noninvasive and will lead to qualitative improvements in forensic pathologic investigation. Future applications of this approach include the assessment of morbidity and mortality in the general population and, perhaps, routine screening of bodies prior to burial.

Post-mortem forensic neuroimaging: correlation of MSCT and MRI findings with autopsy results

Multislice-computed tomography (MSCT) and magnetic resonance imaging (MRI) are increasingly used for forensic purposes. Based on broad experience in clinical neuroimaging, post-mortem MSCT and MRI were performed in 57 forensic cases with the goal to evaluate the radiological methods concerning their usability for forensic head and brain examination. An experienced clinical radiologist evaluated the imaging data. The results were compared to the autopsy findings that served as the gold standard with regard to common forensic neurotrauma findings such as skull fractures, soft tissue lesions of the scalp, various forms of intracranial hemorrhage or signs of increased brain pressure. The sensitivity of the imaging methods ranged from 100% (e.g., heat-induced alterations, intracranial gas) to zero (e.g., mediobasal impression marks as a sign of increased brain pressure, plaques jaunes). The agreement between MRI and CT was 69%. The radiological methods prevalently failed in the detection of lesions smaller than 3mm of size, whereas they were generally satisfactory concerning the evaluation of intracranial hemorrhage. Due to its advanced 2D and 3D post-processing possibilities, CT in particular possessed certain advantages in comparison with autopsy with regard to forensic reconstruction. MRI showed forensically relevant findings not seen during autopsy in several cases. The partly limited sensitivity of imaging that was observed in this retrospective study was based on several factors: besides general technical limitations it became apparent that clinical radiologists require a sound basic forensic background in order to detect specific signs. Focused teaching sessions will be essential to improve the outcome in future examinations. On the other hand, the autopsy protocols should be further standardized to allow an exact comparison of imaging and autopsy data. In consideration of these facts, MRI and CT have the power to play an important role in future forensic neuropathological examination.

Postmortem noninvasive virtual autopsy: extrapleural hemorrhage after blunt thoracic trauma

A 19-year-old man speeding recklessly along a highway caused a left-frontal crash with another car. After his vehicle came to a standstill, he climbed out of the wreck and crawled across the tarmac to the other side of the road, where he died several minutes after the accident and before the arrival of an ambulance. Postmortem multislice computed tomography (MSCT) demonstrated fractures of the first, second, and third ribs and scapula on the left, an extrapleural hemorrhage in the apical region of the left thorax, as well as a large amount of blood in the left thoracic cavity. These radiologic findings were indicative of a delayed rupture of a traumatic extrapleural hematoma into the pleural space. A traditional autopsy confirmed the very rare diagnosis of a traumatic extrapleural hemorrhage with a delayed rupture.

Virtopsy - the concept of a centralized database in forensic medicine for analysis and comparison of radiological and autopsy data

Recent developments in clinical radiology have resulted in additional developments in the field of forensic radiology. After implementation of cross-sectional radiology and optical surface documentation in forensic medicine, difficulties in the validation and analysis of the acquired data was experienced. To address this problem and for the comparison of autopsy and radiological data a centralized database with internet technology for forensic cases was created. The main goals of the database are (1) creation of a digital and standardized documentation tool for forensic-radiological and pathological findings; (2) establishing a basis for validation of forensic cross-sectional radiology as a non-invasive examination method in forensic medicine that means comparing and evaluating the radiological and autopsy data and analyzing the accuracy of such data; and (3) providing a conduit for continuing research and education in forensic medicine. Considering the infrequent availability of CT or MRI for forensic institutions and the heterogeneous nature of case material in forensic medicine an evaluation of benefits and limitations of cross-sectional imaging concerning certain forensic features by a single institution may be of limited value. A centralized database permitting international forensic and cross disciplinary collaborations may provide important support for forensic-radiological casework and research.

Virtual autopsy using imaging: bridging radiologic and forensic sciences. A review of the Virtopsy and similar projects

The transdisciplinary research project Virtopsy is dedicated to implementing modern imaging techniques into forensic medicine and pathology in order to augment current examination techniques or even to offer alternative methods. Our project relies on three pillars: three-dimensional (3D) surface scanning for the documentation of body surfaces, and both multislice computed tomography (MSCT) and magnetic resonance imaging (MRI) to visualise the internal body. Three-dimensional surface scanning has delivered remarkable results in the past in the 3D documentation of patterned injuries and of objects of forensic interest as well as whole crime scenes. Imaging of the interior of corpses is performed using MSCT and/or MRI. MRI, in addition, is also well suited to the examination of surviving victims of assault, especially choking, and helps visualise internal injuries not seen at external examination of the victim. Apart from the accuracy and three-dimensionality that conventional documentations lack, these techniques allow for the re-examination of the corpse and the crime scene even decades later, after burial of the corpse and liberation of the crime scene. We believe that this virtual, non-invasive or minimally invasive approach will improve forensic medicine in the near future.

VIRTOPSY - the Swiss virtual autopsy approach

The aim of the VIRTOPSY project () is utilizing radiological scanning to push low-tech documentation and autopsy procedures in a world of high-tech medicine in order to improve scientific value, to increase significance and quality in the forensic field. The term VIRTOPSY was created from the terms virtual and autopsy: Virtual is derived from the Latin word 'virtus', which means 'useful, efficient and good'. Autopsy is a combination of the old Greek terms 'autos' (=self) and 'opsomei' (=I will see). Thus autopsy means 'to see with ones own eyes'. Because our goal was to eliminate the subjectivity of "autos", we merged the two terms virtual and autopsy - deleting "autos" - to create VIRTOPSY. Today the project VIRTOPSY combining the research topics under one scientific umbrella, is characterized by a trans-disciplinary research approach that combines Forensic Medicine, Pathology, Radiology, Image Processing, Physics, and Biomechanics to an international scientific network. The paper will give an overview of the Virtopsy change process in forensic medicine.

Inhalant deaths in South Australia: a 20-year retrospective autopsy study

A 20-year retrospective study of inhalant deaths in South Australia, autopsied at Forensic Science SA, was undertaken from January 1983 to December 2002. Thirty-nine cases were identified from an autopsy pool of 18,880 cases, with a male to female ratio of 12:1. Sixty-four percent of the victims (N = 25) died during voluntary inhalation of volatile substances and 28% (N = 11) committed suicide utilizing a volatile substance or gas. The remaining 3 cases involved a workplace accident (N = 1) and 2 cases of autoerotic death where inhalants were being used to augment solitary sexual activity. The mean age of the 28 victims of accidental inhalant death of 21 years (range, 13-45 years) was considerably less than that of the 11 suicide victims of 31.5 years (range, 17-48 years). No homicides were found. Approximately one quarter of the victims were Aboriginal (N = 11), 10 of whom had died as a result of gasoline inhalation ("petrol sniffing"). Other common substances of abuse were aliphatic hydrocarbons such as butane. The study has shown that those most at risk for accidental or suicidal inhalant deaths were young males, with 92% of victims overall being male, and with 77% of victims being under 31 years of age. Gasoline inhalation remains a significant problem in Aboriginal communities in South Australia.