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VIRTOPSY: Minimally Invasive, Imaging-guided Virtual Autopsy

¹ From the Institute of Forensic Medicine, University of Bern, Buehlstrasse 20, CH-3012 Bern, Switzerland (R.D., C.J., M.J.T.); the Institute of Diagnostic Radiology, Inselspital, University of Bern, Bern, Switzerland (P.V.); and the Armed Forces Institute of Pathology, MRM Facility, Washington, DC (K.P.). Presented as an education exhibit at the 2003 RSNA Annual Meeting. Received January 3, 2006; revision requested January 30 and received March 23; accepted March 24. All authors have no financial relationships to disclose. Address correspondence to M.J.T. (e-mail: michael.thali{at}irm.unibe.ch).

	Abstract

Top Abstract Introduction Clinical Experience Results Conclusions References

 
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.

© RSNA, 2006

	Introduction

Top Abstract Introduction Clinical Experience Results Conclusions References

 
The main objectives of forensic medicine are to document, analyze, and elucidate scientific medical findings in both living and deceased persons in a comprehensible way for courtroom presentation. In deceased persons, the main goals are to determine the cause and manner of death, to evaluate the vitality of the sustained injuries, and to develop a forensic reconstruction based on the findings. Other than in forensic genetics (in which DNA is used) and forensic toxicology—areas in which "high-tech" methods have already been incorporated into the daily routine—the documentation of forensic pathologic findings is still predominantly based on the same autopsy techniques and protocols that have been used for centuries. The most commonly used tools are a scalpel, verbal description, and conventional two-dimensional photography (1). Forensic findings are thereby documented in an unintentionally subjective (observer-dependent) way, and findings that have not been documented are irrevocably destroyed if the body has been sent to the crematory. For many years, the application of imaging methods for objective nondestructive documentation of relevant forensic findings has lagged far behind the technical development of the imaging methods themselves. There are only a few textbooks available that deal with forensic radiology, most of which concentrate on conventional radiography and do not discuss newer sectional imaging techniques such as computed tomography (CT) and magnetic resonance (MR) imaging in detail. Brogdon (2), in his book Forensic Radiology, makes the following statement: "The sad truth is that a century after the first x-ray was introduced as evidence in a law court, there is no general appreciation of the extent of the radiology potential in the forensic sciences." In principle, all clinical applications of radiologic methods can also be used for forensic purposes (Table). Diagnostic imaging is still underused in forensics, mainly due to unawareness of its potential and the lack of teaching and experience (2–4).

The use of full-body postmortem MR imaging in nonforensic cases for the detection of gross cranial, thoracic, and abdominal disease has been described by a number of different groups (11–22). Limited single-organ studies have been performed by some forensic groups, mainly for the visualization of gunshot wound tracks in the brain (17,23,24). None of these groups performed systematic whole-body examinations using a combination of multisection CT and MR imaging.

It was suggested that conventional autopsy, nowadays often rejected by family members or not tolerated by religions in a multicultural society, might be replaced by noninvasive imaging documentation and, when required, by minimally invasive imaging-guided tissue sampling and by angiography to address vascular questions. The digitally acquired data could be reconsulted whenever new questions arose or could be sent to other experts for a second opinion.

The concept of objective, noninvasive documentation of the body surface for forensic purposes arose in the early 1990s with the development of forensic photogrammetry (25). As is usual in forensic science, this idea was born of and stimulated by a pressing need—in this case, a very high-profile homicide in Switzerland. The case required that a possible murder weapon be compared with an impression on the skull of the victim to identify the weapon with a high degree of certainty. In 2000, it was suggested that observer-independent documentation of the body surface be combined with observer-independent documentation of the interior of the body.

The Virtopsy project of the Institutes of Forensic Medicine, Diagnostic Radiology, and Neuroradiology at the University of Bern, Switzerland, attempts to achieve this combined documentation. Through close collaboration between these institutes, modern cross-sectional techniques were performed for forensic purposes. The term "virtopsy" was created from the terms "virtual" and "autopsy." The former term is derived from the Latin word virtus, which means "useful, efficient, and good." The term "autopsy" is a combination of the classical Greek terms autos ("self") and opsomei ("I will see"). Thus, autopsy means "to see with one’s own eyes." Because our goal was to eliminate the subjectivity implied by autos, we merged the terms "virtual" and "autopsy"—deleting autos—to create the term "virtopsy" (26).

Virtopsy basically consists of (a) body volume documentation and analysis using CT, MR imaging, and microradiology; and (b) 3D body surface documentation using forensic photogrammetry and 3D optical scanning. The resulting data set contains high-resolution 3D color-encoded documentation of the body surface and 3D volume documentation of the interior of the body (Fig 1). By manipulating the data set with volume-rendering (VR) tools at a workstation, one can perform a virtual autopsy anytime, in any place. No forensic findings are disturbed, as they would be by the destructive techniques used in traditional autopsy. The aim of the Virtopsy project is to validate this new approach by systematically comparing the radiologic and surface scanning findings with those obtained at traditional autopsy.

View larger version (15K): [in this window] [in a new window] [Download PPT slide]   Figure 1.  Chart illustrates the Virtopsy project, in which forensic information is acquired with various radiologic methods.

In this article, we discuss and illustrate the use of 3D optical and photogrammetric surface scanning combined with CT and MR imaging for postmortem investigation. We also discuss the correlation of these imaging findings with the forensic findings obtained at traditional autopsy.

	Clinical Experience

Top Abstract Introduction Clinical Experience Results Conclusions References

 
Case Samples
The study was approved by the local department of justice and the Ethics Committee of the University of Bern and, as of this writing, includes 120 forensic cases involving persons whose age at death ranged from 22 weeks gestation to 94 years.

Each body was wrapped in two artifact-free body bags to avoid contaminating the radiology equipment and to protect the identity of the deceased person during clinical scanning. Because the Institute of Forensic Medicine owns a six–detector row scanner (Emotion 6; Siemens Medical Systems, Erlangen, Germany), only contaminated or putrefied bodies are wrapped for CT.

Imaging Considerations
Multisection CT.— CT was performed on a four– or six–detector row scanner. Whole-body scans were performed with a collimation of 1 or 1.25 mm. Up to 1200 axial images were obtained, with a section thickness of 1.25 mm and an increment of 0.7 mm in soft-tissue and osseous kernels. For areas of special forensic importance (special fracture systems, teeth, foreign bodies), additional raw data were acquired with a collimation of 0.5 mm and 0.625-mm-thick sections were calculated. Acquisition time was approximately 10 minutes.

MR Imaging.— MR imaging of the head, thorax, and abdomen was performed on a 1.5-T system (Signa v5.8; GE Medical Systems, Milwaukee, Wis), and further areas of interest (eg, the neck in cases of strangulation, extremities when injured) were added. We acquired coronal, sagittal, and axial images with different contrast weighting (T1-weighted spin-echo and T2-weighted fast spin-echo sequences with and without fat saturation, turbo inversion recovery sequences, gradient-echo sequences). Occasionally, when cardiac findings were expected or observed on axial images, short-axis, horizontal long-axis, and vertical long-axis images were acquired. Acquisition time ranged from 1.5 to 3.5 hours.

Data analysis and postprocessing of CT and MR imaging data were performed on a Leonardo (Siemens) workstation.

Micro-CT.— In special situations, bone-tissue specimens were examined on a micro-CT system developed and built at the Institute of Medical Physics in Erlangen, Germany. This scanner can image a 3D volume with an isotropic resolution ranging from 10 to 100 µm (28). The system allows the examination of samples with diameters ranging from 4 to 40 mm.

MR Microscopy.— MR microscopic studies were performed at room temperature on a Bruker DMX spectrometer (Bruker Biospin MRI, Billerica, Mass) coupled to a wide-bore magnet operating at 9.4 T (400 MHz for protons). Formalin-fixed eyeballs were washed in phosphate-buffered saline solution, blotted dry, and placed in a 25-mm glass tube filled with Fluorinert (Oakwood Products, West Columbia, SC) prior to imaging. Three-dimensional anatomic images were acquired with a fat-suppressed rapid acquisition with relaxation enhancement (RARE) T1-weighted imaging sequence (repetition time msec/echo time msec = 200/8, number of signals acquired = 16, acquisition time = 9.5 hours). Voxels were typically 78 µm in size (3). After imaging was completed, the eyeballs were cut in half and prepared for paraffin embedding. Histologic sections 6 µm thick were cut and then stained with hematoxylin-eosin (H-E) stain to help distinguish hemorrhage from eye tissue.

Photogrammetry-based 3D Optical Scanning.— At present, the standard for the documentation of injuries in forensic medicine is still photography with exact measurements. However, like conventional radiography, the photographic process displays a 3D wound in only two dimensions.

With the TRITOP/ATOS II system (GOM, Braunschweig, Germany), the 3D color-encoded surface can be documented by means of detection of the distortion of light stripes projected onto the surface. In this way, the system can recalculate the 3D surface that caused the distortion. This system is usually used when high precision is required, since it is accurate to less than 20 µm. This accuracy allows more detailed surface documentation compared with 3D reconstructed images from high-resolution CT data.

The color information is acquired using TRI-TOP software, which combines digital photographs of the surface taken from many different angles to create a single 3D color image of the object that can be matched up with the digital 3D surface image of the object with use of coded and uncoded markers placed on the object. With this technology, documentation ranging from that of fine details (eg, skin lesion) to overview documentation (whole body or entire vehicle) is possible.

Logistics
Most of the cross-sectional imaging of bodies performed on the clinical scanners at the Institutes of Diagnostic Radiology and Neuroradiology was performed during evening hours or weekends. A local mortician worked out the necessary logistics between the two institutes.

Correlation of Cross-Sectional with Traditional Autopsy Findings
After forensic autopsy had been performed by board-certified forensic pathologists with detailed digital photographic documentation of all findings, a correlation was performed according to the Armed Forces Institute of Pathology (AFIP) design (29,30).

	Results

Top Abstract Introduction Clinical Experience Results Conclusions References

 
The cases illustrated in this article are predominantly of special interest in the forensic domain. The postmortem imaging appearance of trauma and organ disease does not differ markedly from their clinical appearances except for overlying postmortem alterations.

Identification
Prior to any postmortem investigation, the identity of the body must be clarified and proved; otherwise, the postmortem investigation has as one of its goals the reestablishment of the identity of the unidentified body. Multi–detector row CT can be of great help in this regard. Secure postmortem identification is possible only on the basis of dental status, DNA profiles, or fingerprinting. Because DNA is the most expensive and time-consuming method, fingerprinting and dental identification are more commonly used. With cranial CT data obtained in a corpse, it is possible to reconstruct any antemortem radiographic projection for comparison (31). Even panoramic images can be created that are comparable to antemortem orthopantograms (32). In addition, the restoration material that was used can be ascertained on the basis of postmortem CT data and correlated with the antemortem dental records of suspected missing persons (33).

In addition to gross morphologic findings such as an endoprosthesis of the shoulder, hip, or knee—findings that are often already expected on the basis of an efficient external inspection—whole-body CT of the corpse reveals numerous findings that can be used for positive identification as well as for exclusion of an assumed identity, conclusions that could not be reached with routine autopsy (Fig 2) (34,35). These applications of CT technology in the forensic domain suggested that mobile machines could be used for postmortem data acquisition in cases of mass casualties such as airplane crashes or natural disasters (eg, the recent tsunami catastrophe in Asia). In these incidents, identification of bodies is the major issue to be addressed, and CT can be of inestimable value in disaster victim identification.

View larger version (70K): [in this window] [in a new window] [Download PPT slide]   Figure 2a.  Corpse identification with CT in four different cases. (a) Oblique VR bone image obtained in a completely burned corpse shows a helical wire in the left humerus representing a rare technique of humeral osteosynthesis. (b) Anteroposterior view of the pelvis shows two screws in the left femur. (c) Anteroposterior view of the knees shows replacement of the right anterior cruciate ligament with screws in the femur and tibia. (d) Anteroposterior view of the lumbar spine shows percutaneous vertebroplasty with cement in the vertebral bodies, a finding that can be used for identification. Routine forensic autopsy would be incapable of demonstrating the findings in a–d.

View larger version (68K): [in this window] [in a new window] [Download PPT slide]   Figure 2b.  Corpse identification with CT in four different cases. (a) Oblique VR bone image obtained in a completely burned corpse shows a helical wire in the left humerus representing a rare technique of humeral osteosynthesis. (b) Anteroposterior view of the pelvis shows two screws in the left femur. (c) Anteroposterior view of the knees shows replacement of the right anterior cruciate ligament with screws in the femur and tibia. (d) Anteroposterior view of the lumbar spine shows percutaneous vertebroplasty with cement in the vertebral bodies, a finding that can be used for identification. Routine forensic autopsy would be incapable of demonstrating the findings in a–d.

View larger version (47K): [in this window] [in a new window] [Download PPT slide]   Figure 2c.  Corpse identification with CT in four different cases. (a) Oblique VR bone image obtained in a completely burned corpse shows a helical wire in the left humerus representing a rare technique of humeral osteosynthesis. (b) Anteroposterior view of the pelvis shows two screws in the left femur. (c) Anteroposterior view of the knees shows replacement of the right anterior cruciate ligament with screws in the femur and tibia. (d) Anteroposterior view of the lumbar spine shows percutaneous vertebroplasty with cement in the vertebral bodies, a finding that can be used for identification. Routine forensic autopsy would be incapable of demonstrating the findings in a–d.

View larger version (57K): [in this window] [in a new window] [Download PPT slide]   Figure 2d.  Corpse identification with CT in four different cases. (a) Oblique VR bone image obtained in a completely burned corpse shows a helical wire in the left humerus representing a rare technique of humeral osteosynthesis. (b) Anteroposterior view of the pelvis shows two screws in the left femur. (c) Anteroposterior view of the knees shows replacement of the right anterior cruciate ligament with screws in the femur and tibia. (d) Anteroposterior view of the lumbar spine shows percutaneous vertebroplasty with cement in the vertebral bodies, a finding that can be used for identification. Routine forensic autopsy would be incapable of demonstrating the findings in a–d.

Cause and Manner of Death
Regardless of the manner of death (ie, natural causes, accident, suicide, homicide, or iatrogenic causes), death can have a variety of causes. Some of these causes are specific to certain organs such as the brain, heart, and lungs. Various systemic findings can also indicate the cause of death.

Brain.— Typical trauma findings at clinical radiology are equally well visualized at postmortem imaging. Increased intracranial pressure as a result of trauma or ischemia typically manifests at autopsy as transtentorial herniation of the temporal lobe or herniation of the cerebellum into the foramen magnum, with impressions at the base of the cerebellum corresponding to the foramen magnum (Fig 3) (39). If there is a gross pathologic finding within the brain responsible for the increased intracranial pressure, postmortem imaging allows detailed visualization (Fig 4). This capacity is especially helpful when advanced stages of putrefaction make impracticable an autopsy investigation of the remaining brain structures when the skull is opened. In such cases, postmortem MR imaging provides an adequate anatomic overview of the brain in situ and allows exclusion of gross pathologic alterations within the brain (40). Recent studies have investigated the sensitivity and significance of postmortem MR imaging for discrete brain alterations. Initial 3-T MR imaging examinations of bodies indicate that the lack of sufficient sensitivity for brain lesions smaller than 5 mm on 1.5-T systems can be overcome by increasing the field strength, with a possible image matrix up to 1024. Furthermore, initial postmortem diffusion tensor imaging studies promise to overcome present cross-sectional imaging limitations in the visualization of small brain lesions within vitally important regions (41).

View larger version (148K): [in this window] [in a new window] [Download PPT slide]   Figure 3a.  Increased intracranial pressure as the cause of death. (a) Coronal T2-weighted MR image shows herniation of basilar parts of the cerebellum into the foramen magnum. (b) Autopsy photograph shows the cerebellum, with swelling of the tonsils (solid arrows) and a pressure mark caused by the foramen magnum (dashed arrows).

View larger version (115K): [in this window] [in a new window] [Download PPT slide]   Figure 3b.  Increased intracranial pressure as the cause of death. (a) Coronal T2-weighted MR image shows herniation of basilar parts of the cerebellum into the foramen magnum. (b) Autopsy photograph shows the cerebellum, with swelling of the tonsils (solid arrows) and a pressure mark caused by the foramen magnum (dashed arrows).

View larger version (144K): [in this window] [in a new window] [Download PPT slide]   Figure 4a.  Traumatic intraaxial bleeding. (a) Axial gradient-recalled acquisition in the steady state image shows local hypointense areas (arrow) in the left temporal lobe that reach the subarachnoidal space. These areas represent degenerative products of hemoglobin and indicate trauma. (b) Autopsy photograph of a slice through the temporal lobe of the formalin-fixed brain shows trauma-related bleeding, predominantly in the cortex and subcortex (arrow).

View larger version (150K): [in this window] [in a new window] [Download PPT slide]   Figure 4b.  Traumatic intraaxial bleeding. (a) Axial gradient-recalled acquisition in the steady state image shows local hypointense areas (arrow) in the left temporal lobe that reach the subarachnoidal space. These areas represent degenerative products of hemoglobin and indicate trauma. (b) Autopsy photograph of a slice through the temporal lobe of the formalin-fixed brain shows trauma-related bleeding, predominantly in the cortex and subcortex (arrow).

View larger version (132K): [in this window] [in a new window] [Download PPT slide]   Figure 5a.  Natural cardiac death. (a) Short-axis T2-weighted MR image shows local hypointense areas (arrow) in the left lateral wall, with areas of hyperintensity in the surrounding myocardial tissue. (b) Photograph of the corresponding autopsy specimen shows hemorrhagic myocardial infarction (arrow) in the lateral wall of the left ventricle. (c) Short-axis T2-weighted MR image obtained in a patient with chronic uremic cardiomyopathy shows massive eccentrically hypertrophic ventricles in a so-called cor bovinum. (d) Photograph of the corresponding autopsy specimen helps confirm biventricular eccentric hypertrophy (heart weight, 1070 g). On all scales shown in the figures, the smallest units are millimeters.

View larger version (111K): [in this window] [in a new window] [Download PPT slide]   Figure 5b.  Natural cardiac death. (a) Short-axis T2-weighted MR image shows local hypointense areas (arrow) in the left lateral wall, with areas of hyperintensity in the surrounding myocardial tissue. (b) Photograph of the corresponding autopsy specimen shows hemorrhagic myocardial infarction (arrow) in the lateral wall of the left ventricle. (c) Short-axis T2-weighted MR image obtained in a patient with chronic uremic cardiomyopathy shows massive eccentrically hypertrophic ventricles in a so-called cor bovinum. (d) Photograph of the corresponding autopsy specimen helps confirm biventricular eccentric hypertrophy (heart weight, 1070 g). On all scales shown in the figures, the smallest units are millimeters.

View larger version (139K): [in this window] [in a new window] [Download PPT slide]   Figure 5c.  Natural cardiac death. (a) Short-axis T2-weighted MR image shows local hypointense areas (arrow) in the left lateral wall, with areas of hyperintensity in the surrounding myocardial tissue. (b) Photograph of the corresponding autopsy specimen shows hemorrhagic myocardial infarction (arrow) in the lateral wall of the left ventricle. (c) Short-axis T2-weighted MR image obtained in a patient with chronic uremic cardiomyopathy shows massive eccentrically hypertrophic ventricles in a so-called cor bovinum. (d) Photograph of the corresponding autopsy specimen helps confirm biventricular eccentric hypertrophy (heart weight, 1070 g). On all scales shown in the figures, the smallest units are millimeters.

View larger version (127K): [in this window] [in a new window] [Download PPT slide]   Figure 5d.  Natural cardiac death. (a) Short-axis T2-weighted MR image shows local hypointense areas (arrow) in the left lateral wall, with areas of hyperintensity in the surrounding myocardial tissue. (b) Photograph of the corresponding autopsy specimen shows hemorrhagic myocardial infarction (arrow) in the lateral wall of the left ventricle. (c) Short-axis T2-weighted MR image obtained in a patient with chronic uremic cardiomyopathy shows massive eccentrically hypertrophic ventricles in a so-called cor bovinum. (d) Photograph of the corresponding autopsy specimen helps confirm biventricular eccentric hypertrophy (heart weight, 1070 g). On all scales shown in the figures, the smallest units are millimeters.

View larger version (121K): [in this window] [in a new window] [Download PPT slide]   Figure 6a.  Cardiac trauma (stab wound to the heart). (a) Short-axis T2-weighted MR image through the cardiac apex shows a myocardial injury (solid white arrow). Subsequent pericardial tamponade manifests as sedimented cellular components (dashed white arrows) with medium signal intensity and an upper layer of serum (black arrows) with increased signal intensity. (b) Photograph of the corresponding autopsy specimen demonstrates transmural laceration of the left ventricle in the apical region (arrow).

View larger version (137K): [in this window] [in a new window] [Download PPT slide]   Figure 6b.  Cardiac trauma (stab wound to the heart). (a) Short-axis T2-weighted MR image through the cardiac apex shows a myocardial injury (solid white arrow). Subsequent pericardial tamponade manifests as sedimented cellular components (dashed white arrows) with medium signal intensity and an upper layer of serum (black arrows) with increased signal intensity. (b) Photograph of the corresponding autopsy specimen demonstrates transmural laceration of the left ventricle in the apical region (arrow).

View larger version (70K): [in this window] [in a new window] [Download PPT slide]   Figure 7a.  Lethal air embolism of the pulmonary artery in the victim of a gunshot wound to the head. (a) Anteroposterior 3D VR image shows the air-filled right ventricle and pulmonary artery. CT-based volumetry showed 59 mL of gas within these two structures. 1 = cranial veins, 2 = trachea, 3 = main pulmonary artery, 4 = right ventricular outflow tract, 5 = intrahepatic veins. (b) Autopsy photograph demonstrates the procedure used to confirm the presence of an air embolism. After the pericardium has been opened, the pericardial space is filled with clear water to totally cover the heart. The right ventricle is then punctured with a scalpel, and turning the scalpel produces ascending air bubbles (arrow).

View larger version (138K): [in this window] [in a new window] [Download PPT slide]   Figure 7b.  Lethal air embolism of the pulmonary artery in the victim of a gunshot wound to the head. (a) Anteroposterior 3D VR image shows the air-filled right ventricle and pulmonary artery. CT-based volumetry showed 59 mL of gas within these two structures. 1 = cranial veins, 2 = trachea, 3 = main pulmonary artery, 4 = right ventricular outflow tract, 5 = intrahepatic veins. (b) Autopsy photograph demonstrates the procedure used to confirm the presence of an air embolism. After the pericardium has been opened, the pericardial space is filled with clear water to totally cover the heart. The right ventricle is then punctured with a scalpel, and turning the scalpel produces ascending air bubbles (arrow).

View larger version (151K): [in this window] [in a new window] [Download PPT slide]   Figure 8a.  Pulmonary edema. (a) Coronal T2-weighted MR image of the thorax shows a global increase in signal intensity throughout the lungs caused by an increased fraction of intrapulmonary water. (b) Photograph of the corresponding autopsy specimen shows the loss of tissue water after sectioning. Note the accumulation of the drained edema (arrows) surrounding the thumbs of the forensic pathologist.

View larger version (137K): [in this window] [in a new window] [Download PPT slide]   Figure 8b.  Pulmonary edema. (a) Coronal T2-weighted MR image of the thorax shows a global increase in signal intensity throughout the lungs caused by an increased fraction of intrapulmonary water. (b) Photograph of the corresponding autopsy specimen shows the loss of tissue water after sectioning. Note the accumulation of the drained edema (arrows) surrounding the thumbs of the forensic pathologist.

View larger version (109K): [in this window] [in a new window] [Download PPT slide]   Figure 9a.  Severe postmortem broncho-pneumonia. (a) CT scan shows complete air displacement in the right lung. Only parts of the left lung are ventilated. (b) Coronal T2-weighted MR image demonstrates increased signal intensity throughout the right lung and in parts of the left lung. Note also the ascites below the diaphragm. (c) Photomicrograph (original magnification, x100; H-E stain) shows purulent bronchitis with massive intraalveolar edema.

View larger version (141K): [in this window] [in a new window] [Download PPT slide]   Figure 9b.  Severe postmortem broncho-pneumonia. (a) CT scan shows complete air displacement in the right lung. Only parts of the left lung are ventilated. (b) Coronal T2-weighted MR image demonstrates increased signal intensity throughout the right lung and in parts of the left lung. Note also the ascites below the diaphragm. (c) Photomicrograph (original magnification, x100; H-E stain) shows purulent bronchitis with massive intraalveolar edema.

View larger version (214K): [in this window] [in a new window] [Download PPT slide]   Figure 9c.  Severe postmortem broncho-pneumonia. (a) CT scan shows complete air displacement in the right lung. Only parts of the left lung are ventilated. (b) Coronal T2-weighted MR image demonstrates increased signal intensity throughout the right lung and in parts of the left lung. Note also the ascites below the diaphragm. (c) Photomicrograph (original magnification, x100; H-E stain) shows purulent bronchitis with massive intraalveolar edema.

View larger version (66K): [in this window] [in a new window] [Download PPT slide]   Figure 10a.  Emphysema aquosum. (a) Thoracic CT scan (lung windowing) demonstrates emphysema aquosum caused by drowning, with anterior contact between the lungs. Note the postmortem sedimentation phenomenon with an increase in attenuation from ventral to dorsal, a finding that is especially visible in the right upper lobe. (b) Anteroposterior 3D VR lung image allows correlation with the traditional autopsy findings (cf c). (c) On an autopsy photograph, the ventral parts of the lungs overlap retrosternally. (d) Anteroposterior maximum-intensity-projection (MIP) image from coronal T2-weighted MR imaging data shows hyperintense contents in the stomach (solid arrow) and duodenum (dashed arrow), findings that indicate active swallowing of drowning fluid. (e) Autopsy photograph shows a distinctively fluid-filled stomach (solid arrow) and duodenum (dashed arrow). The organs were opened to sample the fluid.

View larger version (99K): [in this window] [in a new window] [Download PPT slide]   Figure 10b.  Emphysema aquosum. (a) Thoracic CT scan (lung windowing) demonstrates emphysema aquosum caused by drowning, with anterior contact between the lungs. Note the postmortem sedimentation phenomenon with an increase in attenuation from ventral to dorsal, a finding that is especially visible in the right upper lobe. (b) Anteroposterior 3D VR lung image allows correlation with the traditional autopsy findings (cf c). (c) On an autopsy photograph, the ventral parts of the lungs overlap retrosternally. (d) Anteroposterior maximum-intensity-projection (MIP) image from coronal T2-weighted MR imaging data shows hyperintense contents in the stomach (solid arrow) and duodenum (dashed arrow), findings that indicate active swallowing of drowning fluid. (e) Autopsy photograph shows a distinctively fluid-filled stomach (solid arrow) and duodenum (dashed arrow). The organs were opened to sample the fluid.

View larger version (158K): [in this window] [in a new window] [Download PPT slide]   Figure 10c.  Emphysema aquosum. (a) Thoracic CT scan (lung windowing) demonstrates emphysema aquosum caused by drowning, with anterior contact between the lungs. Note the postmortem sedimentation phenomenon with an increase in attenuation from ventral to dorsal, a finding that is especially visible in the right upper lobe. (b) Anteroposterior 3D VR lung image allows correlation with the traditional autopsy findings (cf c). (c) On an autopsy photograph, the ventral parts of the lungs overlap retrosternally. (d) Anteroposterior maximum-intensity-projection (MIP) image from coronal T2-weighted MR imaging data shows hyperintense contents in the stomach (solid arrow) and duodenum (dashed arrow), findings that indicate active swallowing of drowning fluid. (e) Autopsy photograph shows a distinctively fluid-filled stomach (solid arrow) and duodenum (dashed arrow). The organs were opened to sample the fluid.

View larger version (145K): [in this window] [in a new window] [Download PPT slide]   Figure 10d.  Emphysema aquosum. (a) Thoracic CT scan (lung windowing) demonstrates emphysema aquosum caused by drowning, with anterior contact between the lungs. Note the postmortem sedimentation phenomenon with an increase in attenuation from ventral to dorsal, a finding that is especially visible in the right upper lobe. (b) Anteroposterior 3D VR lung image allows correlation with the traditional autopsy findings (cf c). (c) On an autopsy photograph, the ventral parts of the lungs overlap retrosternally. (d) Anteroposterior maximum-intensity-projection (MIP) image from coronal T2-weighted MR imaging data shows hyperintense contents in the stomach (solid arrow) and duodenum (dashed arrow), findings that indicate active swallowing of drowning fluid. (e) Autopsy photograph shows a distinctively fluid-filled stomach (solid arrow) and duodenum (dashed arrow). The organs were opened to sample the fluid.

View larger version (118K): [in this window] [in a new window] [Download PPT slide]   Figure 10e.  Emphysema aquosum. (a) Thoracic CT scan (lung windowing) demonstrates emphysema aquosum caused by drowning, with anterior contact between the lungs. Note the postmortem sedimentation phenomenon with an increase in attenuation from ventral to dorsal, a finding that is especially visible in the right upper lobe. (b) Anteroposterior 3D VR lung image allows correlation with the traditional autopsy findings (cf c). (c) On an autopsy photograph, the ventral parts of the lungs overlap retrosternally. (d) Anteroposterior maximum-intensity-projection (MIP) image from coronal T2-weighted MR imaging data shows hyperintense contents in the stomach (solid arrow) and duodenum (dashed arrow), findings that indicate active swallowing of drowning fluid. (e) Autopsy photograph shows a distinctively fluid-filled stomach (solid arrow) and duodenum (dashed arrow). The organs were opened to sample the fluid.

View larger version (142K): [in this window] [in a new window] [Download PPT slide]   Figure 11a.  Hypothermia. (a) Coronal reformatted short inversion time inversion-recovery image of the lower abdomen shows areas of bleeding (arrow) within the body core (left psoas muscle) with no causative trauma. (b) Autopsy photograph shows the left psoas muscle with a local intramuscular hematoma (arrow) and no injury to the surrounding tissue.

View larger version (139K): [in this window] [in a new window] [Download PPT slide]   Figure 11b.  Hypothermia. (a) Coronal reformatted short inversion time inversion-recovery image of the lower abdomen shows areas of bleeding (arrow) within the body core (left psoas muscle) with no causative trauma. (b) Autopsy photograph shows the left psoas muscle with a local intramuscular hematoma (arrow) and no injury to the surrounding tissue.

View larger version (94K): [in this window] [in a new window] [Download PPT slide]   Figure 12a.  Fatal hemorrhage. 1 = superior vena cava, 2 = ascending aorta, 3 = main pulmonary artery. (a) Postmortem CT scan obtained at the level of the right pulmonary artery in a case in which elevated intracranial pressure was the cause of death shows normal vessel dimensions. (b) Postmortem CT scan obtained at the level of the right pulmonary artery in a different case demonstrates fatal hemorrhage with collapsed thoracic vessels.

View larger version (85K): [in this window] [in a new window] [Download PPT slide]   Figure 12b.  Fatal hemorrhage. 1 = superior vena cava, 2 = ascending aorta, 3 = main pulmonary artery. (a) Postmortem CT scan obtained at the level of the right pulmonary artery in a case in which elevated intracranial pressure was the cause of death shows normal vessel dimensions. (b) Postmortem CT scan obtained at the level of the right pulmonary artery in a different case demonstrates fatal hemorrhage with collapsed thoracic vessels.

Vitality of Sustained Injuries
Vital reactions elucidate the sequence of injury and death in forensic pathologic investigations. The question of whether an injury was sustained before or after death can be an important forensic matter. The answer is provided by forensic findings that occur only with intact circulation (eg, fatal hemorrhage, air and fat embolism), respiration (eg, aspiration, cutaneous emphysema), metabolism, or consciousness. These findings are known as forensic vital reactions.

Trauma.— Aspirated material, whether blood, gastric contents, or soot, reveals ongoing ventilation after trauma (Fig 13), just as extensive soft-tissue emphysema does in blunt trauma (Fig 14). After soft-tissue emphysema is palpated, it is hardly visible at autopsy because the air disappears when the overlying skin is incised. Active swallowing of foreign material can also demonstrate that the victim was still alive when the incident happened (Figs 10, 15).

View larger version (60K): [in this window] [in a new window] [Download PPT slide]   Figure 13a.  Aspiration as a postmortem sign of vitality of sustained injuries in a man who was killed in an airplane crash. (a) Thoracic CT scan shows a local hyperattenuating area (arrow) in the right lower lobe. (b) Autopsy photograph of a lung specimen reveals aspirated blood (arrows), a finding that indicates that the victim was still alive when he sustained the injuries.

View larger version (151K): [in this window] [in a new window] [Download PPT slide]   Figure 13b.  Aspiration as a postmortem sign of vitality of sustained injuries in a man who was killed in an airplane crash. (a) Thoracic CT scan shows a local hyperattenuating area (arrow) in the right lower lobe. (b) Autopsy photograph of a lung specimen reveals aspirated blood (arrows), a finding that indicates that the victim was still alive when he sustained the injuries.

View larger version (106K): [in this window] [in a new window] [Download PPT slide]   Figure 14.  Soft-tissue emphysema as a vital sign of trauma in a pedestrian who had been rolled over by a car. Abdominal CT scan demonstrates massive soft-tissue emphysema (arrowheads). Distinctive air collections between the subcutis and the muscle as well as within the soft tissues indicate that ventilation continued for some time after the accident.

View larger version (170K): [in this window] [in a new window] [Download PPT slide]   Figure 15a.  Swallowed foreign bodies as a vital sign in a person who died in an automobile accident. (a) Thoracic CT scan shows a foreign body (arrow) in the esophagus. The image fails to demonstrate any traumatic injury to the esophagus that might represent an entry wound, a finding that indicates active swallowing of the foreign body. (b) Autopsy photograph of the opened esophagus shows multiple small pieces of windshield (arrows) that have partly lacerated the mucosa.

View larger version (155K): [in this window] [in a new window] [Download PPT slide]   Figure 15b.  Swallowed foreign bodies as a vital sign in a person who died in an automobile accident. (a) Thoracic CT scan shows a foreign body (arrow) in the esophagus. The image fails to demonstrate any traumatic injury to the esophagus that might represent an entry wound, a finding that indicates active swallowing of the foreign body. (b) Autopsy photograph of the opened esophagus shows multiple small pieces of windshield (arrows) that have partly lacerated the mucosa.

View larger version (114K): [in this window] [in a new window] [Download PPT slide]   Figure 16a.  Vital signs in a case of suicide by hanging. (a) Sagittal T2-weighted MR image shows areas of hyperintensity (arrow) around the sternoclavicular insertions of the sternocleidomastoid muscle. (b) Autopsy photograph reveals areas of bleeding (arrow) around the insertions of the sternocleidomastoid muscle, findings that indicate ongoing circulation at the onset of strangulation. (c) CT scan of the neck demonstrates massive soft-tissue emphysema below the strangulation mark. The air ascends from a pneumomediastinum that was caused by a rupture of alveoles during breathing attempts against occluded airways, thereby serving as a vital sign. Demonstration at autopsy is nearly impossible because the first incision allows the air to escape; therefore, the air must be palpated at autopsy. (d) Coronal T2-weighted MR image demonstrates a hyperintense lymph node (arrow) on the left side of the neck. (e) Autopsy photograph of the formalin-fixed specimen shows the lymph node with hemorrhage.

View larger version (125K): [in this window] [in a new window] [Download PPT slide]   Figure 16b.  Vital signs in a case of suicide by hanging. (a) Sagittal T2-weighted MR image shows areas of hyperintensity (arrow) around the sternoclavicular insertions of the sternocleidomastoid muscle. (b) Autopsy photograph reveals areas of bleeding (arrow) around the insertions of the sternocleidomastoid muscle, findings that indicate ongoing circulation at the onset of strangulation. (c) CT scan of the neck demonstrates massive soft-tissue emphysema below the strangulation mark. The air ascends from a pneumomediastinum that was caused by a rupture of alveoles during breathing attempts against occluded airways, thereby serving as a vital sign. Demonstration at autopsy is nearly impossible because the first incision allows the air to escape; therefore, the air must be palpated at autopsy. (d) Coronal T2-weighted MR image demonstrates a hyperintense lymph node (arrow) on the left side of the neck. (e) Autopsy photograph of the formalin-fixed specimen shows the lymph node with hemorrhage.

View larger version (112K): [in this window] [in a new window] [Download PPT slide]   Figure 16c.  Vital signs in a case of suicide by hanging. (a) Sagittal T2-weighted MR image shows areas of hyperintensity (arrow) around the sternoclavicular insertions of the sternocleidomastoid muscle. (b) Autopsy photograph reveals areas of bleeding (arrow) around the insertions of the sternocleidomastoid muscle, findings that indicate ongoing circulation at the onset of strangulation. (c) CT scan of the neck demonstrates massive soft-tissue emphysema below the strangulation mark. The air ascends from a pneumomediastinum that was caused by a rupture of alveoles during breathing attempts against occluded airways, thereby serving as a vital sign. Demonstration at autopsy is nearly impossible because the first incision allows the air to escape; therefore, the air must be palpated at autopsy. (d) Coronal T2-weighted MR image demonstrates a hyperintense lymph node (arrow) on the left side of the neck. (e) Autopsy photograph of the formalin-fixed specimen shows the lymph node with hemorrhage.

View larger version (116K): [in this window] [in a new window] [Download PPT slide]   Figure 16d.  Vital signs in a case of suicide by hanging. (a) Sagittal T2-weighted MR image shows areas of hyperintensity (arrow) around the sternoclavicular insertions of the sternocleidomastoid muscle. (b) Autopsy photograph reveals areas of bleeding (arrow) around the insertions of the sternocleidomastoid muscle, findings that indicate ongoing circulation at the onset of strangulation. (c) CT scan of the neck demonstrates massive soft-tissue emphysema below the strangulation mark. The air ascends from a pneumomediastinum that was caused by a rupture of alveoles during breathing attempts against occluded airways, thereby serving as a vital sign. Demonstration at autopsy is nearly impossible because the first incision allows the air to escape; therefore, the air must be palpated at autopsy. (d) Coronal T2-weighted MR image demonstrates a hyperintense lymph node (arrow) on the left side of the neck. (e) Autopsy photograph of the formalin-fixed specimen shows the lymph node with hemorrhage.

View larger version (55K): [in this window] [in a new window] [Download PPT slide]   Figure 16e.  Vital signs in a case of suicide by hanging. (a) Sagittal T2-weighted MR image shows areas of hyperintensity (arrow) around the sternoclavicular insertions of the sternocleidomastoid muscle. (b) Autopsy photograph reveals areas of bleeding (arrow) around the insertions of the sternocleidomastoid muscle, findings that indicate ongoing circulation at the onset of strangulation. (c) CT scan of the neck demonstrates massive soft-tissue emphysema below the strangulation mark. The air ascends from a pneumomediastinum that was caused by a rupture of alveoles during breathing attempts against occluded airways, thereby serving as a vital sign. Demonstration at autopsy is nearly impossible because the first incision allows the air to escape; therefore, the air must be palpated at autopsy. (d) Coronal T2-weighted MR image demonstrates a hyperintense lymph node (arrow) on the left side of the neck. (e) Autopsy photograph of the formalin-fixed specimen shows the lymph node with hemorrhage.

View larger version (60K): [in this window] [in a new window] [Download PPT slide]   Figure 17.  Assessment of impact direction in a pedestrian who was struck by an automobile. Anteroposterior 3D VR image shows fractures of the left tibia and fibula, with a wedge-shaped fracture piece (white arrow). The base of the wedge indicates the direction of the force that caused the fracture (red arrow).

View larger version (102K): [in this window] [in a new window] [Download PPT slide]   Figure 18a.  Fat contusion with formation of a subcutaneous cavity in a person who was rolled over by a car. (a) Coronal fat-saturated MR image of the thigh displays high-signal-intensity areas (arrow) within the subcutaneous tissue, findings that represent a fat contusion at the site of impact. (b) Axial T2-weighted MR image of the left lateral gluteal area shows contusion and disconnection between the muscle fascia and the subcutaneous fat (décollement injury) (arrow). The formed wound cavity is filled with liquefied fat and blood, and the sedimentation of the cellular blood components has resulted in an upper layer of hyperintense serum. (c) Autopsy photograph shows a typical décollement injury, with subcutaneous fat disconnected from the fascia.

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