Forensic Science International

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Serial postmortem thoracic radiographic ﬁndings in canine cadavers

Hock Gan Heng

a,b,

_*

_{, Gayathri Thevi Selvarajah}

b,c

_{, Hiang Tee Lim}

b

_{, Jin Seng Ong}

b

_,

Jiehan Lim

b

, Jin Tatt Ooi

b

a

Department of Veterinary Clinical Sciences, Purdue University, 625, Harrison Street, West Lafayette, IN 47907, United States b

Faculty of Veterinary Medicine, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia c

Department of Clinical Sciences of Companion Animals, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 104, 3584 CM, Utrecht, Netherlands

1. Introduction

Postmortem radiographic examination as an ancillary investi-gation prior to traditional necropsy can detect changes which could not easily be seen on traditional necropsy[1–3]. Forensic radiology in animals is often performed in judicial investigation to rule out gunshot and fractures due to cruelty[2,4]. A whole body skeletal radiological survey is recommended before an autopsy on suspected fatal case of abused animals and humans as the abused victims were more likely to have multiple fractures [1–3]. Postmortem radiographic examination of a dead cat revealed multiple sites of venous air embolism as a result of air entering the venous system by crossing damaged vascular walls secondary to insufﬂation of a pharyngeal diverticulum prior to death [5]. Radiological detection of intravascular gas in dead fetuses in dogs with late term pregnancies had been reported[6].

The use of computed tomography and magnetic resonance in the postmortem radiographic examination is termed virtual autopsy [7–8]. This helped to detect internal bleeding, bullet paths, brain contusion, gas embolism, blood aspiration to the lung

and hidden fracture hard to find in a traditional necropsy[7,9–10]. Various post-processing techniques can be used to provide strong forensic evidence for use in legal proceedings[7]. Virtual autopsy supplement may be partially replacing the conventional necropsy in human medicine. This is because it is more acceptable as many people are dismayed at the idea of the body of their beloved one being mutilated[7]. Computed tomography guided postmortem tissue sampling in human cadavers had been recommended in cases where conventional necropsy is refused[11]. Investigation of an illegal lynx shooting by plain radiography and three-dimen-sional multislice computed tomography had been reported [4]. Computed tomography evaluation of postmortem changes of melon, bone, blubber and mandibular fat of bottlenose dolphin revealed that there were no statistically significant differences of Hounsfield values of the organs examined[12].

Formation of putrefactive gas in the vascular system, body cavities and soft tissues secondary to decomposition of the cadavers makes interpretation of postmortem radiology of the thorax and abdomen in both human and animal more complicated[7,13]. In humans, investigations of thoracic postmortem changes revealed that detection of intracardial and sub-endocardial gas, and postmortem clotting with sedimentation of the blood components were normal ﬁndings of postmortem tomography and MRI [14]. Postmortem dilatation of the heart was documented by computed tomography[15]. Gas was detected in the cardiovascular system secondary to cardiopulmonary resuscitation [16]. Increased

A R T I C L E I N F O Article history:

Received 19 September 2008 Accepted 31 March 2009 Available online 24 April 2009 Keywords:

Postmortem radiograph Canine cadavers Thorax

A B S T R A C T

Postmortem radiographic examinations of animals are often performed in judicial investigation to rule out gunshot and fractures due to cruelty. Literature describing postmortem changes seen on radiographs of animals is rarely available. Serial thoracic radiography of six recently euthanized dogs was performed in an interval of 8 h at a tropical ambient temperature of 22–338C. Severe decomposition of the cadavers prevented the study to be performed beyond 24 h. Gradual increment of gas accumulation in the pleural cavity, mediastinum, esophagus, blood vessels, cardiac chambers and subcutaneous tissue was observed. Lung changes observed were typical of alveolar pattern and subsequently collapsed secondary to severe pneumothorax. Vacuum phenomenon of the scapulohumeral joints which was not documented in humans was seen in four cadavers. Most radiographic changes were detected at 16 h post-euthanasia. Severe subcutaneous emphysema developed between 16 and 24 h post-euthanasia. This study showed that rapid postmortem changes which could be detected radiographically occur within 24 h of death at the ambient temperature of 22–338C.

* Corresponding author at: Department of Veterinary Clinical Sciences, Purdue University, 625, Harrison Street, West Lafayette, IN 47907, United States. Tel.: +1 765 494 0821; fax: +1 765 494 7276.

E-mail address:[email protected](H.G. Heng).

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attenuation of the dependent lungs secondary to pulmonary congestion detected on postmortem computed tomography was a common postmortem finding in human cadavers [17]. A recent study on postmortem abdominal radiographs of feline cadavers performed within 12 h of death revealed the presence of intravas-cular gas in 27% of the cadavers[13]. The gas was detected in abdominal aorta, femoral artery, celiac and cranial mesenteric arteries, and caudal superficial epigastric artery, and also in the parenchyma of liver and spleen [13]. However, there was no information on the postmortem changes of the thorax in animals. Information such as the production of putrefactive gas in relation to postmortem interval may be helpful in estimating the time of death in animals. In addition to this, knowledge of normal postmortem radiographic findings is needed to help differentiate antemortem injuries and postmortem artifacts especially in cases involving medicolegal investigation[18]. Therefore, this prospective study was conducted to document the postmortem radiographic changes in relation to postmortem interval in the thorax of canine cadavers at tropical ambient temperature.

2. Materials and methods

Six pound dogs consisting of four males and two females from Kuala Lumpur City Hall, Malaysia, that were scheduled for humane euthanasia were included in this prospective study. General physical examination and basic hematological profiling was carried out on all six dogs. Dogs were observed for defecation and urination as an indication of its state of health. All dogs were fasted for 12 h, however water was provided ad libitum till 2 h prior to humane euthanasia. Left and right lateral and ventrodorsal thoracic radiographs were performed immediately after euthanasia and at intervals of 8 h thereafter. The cadavers were kept at the normal average ambient temperature of 22–338C on left lateral recumbency and were only manipulated every 8 h for the positioning of radiography. The radiographs were interpreted by a single board-certified radiologist (Heng). Radiographic changes such as presence of gas and/or fluid in the pleural cavity, cranial mediastinum and gas in the blood vessels and cardiac chambers were observed. The size of the cardiac silhouettes was estimated by using the vertebra heart sum method[19]. The width of the thoracic caudal vena cava was measured between the diaphragm and the cardiac silhouette. Length of 4th thoracic vertebra was measured. A ratio of the width of thoracic caudal vena cava and length of 4th thoracic vertebra were calculated. A Student’s pairedt-test was used to calculate the differences in this ratio between the immediate post-euthanasia and 8, 16 and 24 h post-euthanasia. The statistical analysis was performed using Microsoft Excel and the statistical significance was set atP<0.05. Changes of the lungs such as alveolar, interstitial, bronchial and vascular pattern and extrathoracic structure were also noted. A simple in situ necropsy examination was conducted on all cadavers 24 h post-euthanasia.

3. Results

3.1. Physical examination and hematology

Generally the dogs were healthy with no apparent abnorm-alities. They were all adult local dogs of similar body size with a body condition score between 2 and 3 out of 5. Palpation of the abdomen did not reveal any pain or mass. Diarrhea was not observed in any dogs. Urination was normal in all dogs. The body temperature and pulse were within normal range. Auscultation of the thorax revealed normal lung sound. Abdominal palpation was not performed in one dog because it was not approachable due to its ﬁerce temperament. Mild leukocytosis ranging from 19.3 to 25109_L 1_{was observed in}

three of the six dogs. Other hematological and biochemistry parameters were unremarkable.

All six dogs had radiographs taken immediately post-eutha-nasia, as well as at 8 and 16 h post-euthanasia. All cadavers were stiffened at 8 h post-euthanasia. Bleeding from nose and gross distention of abdomen were present at 16 h post-euthanasia. Radiographs were not made in three cadavers at 24 h post-euthanasia due to extremely distended abdomen and excessive serosanguineous discharges from the oriﬁces.

3.2. Radiographic ﬁndings

The pleural cavity was normal in all cadavers immediately post-euthanasia. Small amount of pleural gas was present in one cadaver after 8 h of euthanasia. At 16 h post-euthanasia, the amount of gas increased in this cadaver whereas small amount of gas was then detected in all cadavers. The amount of pleural gas was found to be increased in two cadavers and was unchanged in one cadaver at 24 h post-euthanasia.

The mediastinum was normal in all cadavers immediately after euthanasia. Small amount of gas was present in the mediastinum at the thoracic inlet in one cadaver at 8 h post-euthanasia. At 16 h post-euthanasia, gas was present at the thoracic inlet of two cadavers where one had a normal mediastinum and in the other cadaver’s mediastinum was impossible to be evaluated due to overlying lung changes. At 24 h post-euthanasia, the amount of gas in the mediastinum was increased in one out of the three remaining cadavers. No free gas was detected in one cadaver and evaluation of the mediastinum in one cadaver was impossible due to severe subcutaneous emphysema. Gas in the mediastinal blood vessels was detected in two out of the three cadavers.

Immediately after euthanasia radiographs revealed that two dogs had abnormal lungs. One had mild mixed alveolar interstitial pattern of the peripheral margins of the right lungs while severe alveolar pattern of the left hemi thorax in another dog. Progression of the alveolar pattern was seen at 8 h post-euthanasia. Interstitial pattern of the lungs was detected in one cadaver with normal lungs. All lungs were abnormal at 16 h post-euthanasia. Five cadavers had alveolar pattern and one had interstitial pattern. At 24 h post-euthanasia, alveolar pattern was unchanged in one cadaver and progressed in another cadaver. Severe lung collapse secondary to pneumothorax occurred in one cadaver.

All dogs had normal cardiac silhouette and pulmonary vasculature immediately after euthanasia. At 8 h post-euthanasia, gas was detected in the heart of two cadavers (Fig. 1). It could be seen on both right and left lateral radiographs. Gas was present in the branches of the coronary vessels, right ventricle and main pulmonary artery. Gas was also seen in the caudal vena cava in one of these cadavers. The gas was not well seen on the ventrodorsal radiograph due to small amount of gas and overlying lung changes. The amount of gas in the heart increased dramatically at 16 h post-euthanasia. Gas was now present in right ventricle, atrium and auricle; left ventricle and atrium; cranial and caudal vena cava; main pulmonary artery, aortic outflow track, aorta and branches of the coronary vessels (Fig. 2). These could be seen on the lateral radiographs. The left atrium and the opening of the pulmonary arteries into the left atrium could only be seen on the left lateral radiograph in one cadaver. Gas in the right and left ventricle as well as main pulmonary artery could be seen on the ventrodorsal radiographs. At 24 h post-euthanasia, there was further increased amount of gas in the heart and they could be identified easily. The left atrium could be identified in both lateral views. However, the opening of the pulmonary veins into the left atrium could only be identified on the left lateral radiographs. There was no difference in the size of the cardiac silhouette at all time intervals of the study.

The range of the ratio of width of the thoracic caudal vena cava to the length of 4th thoracic vertebra was 0.71–1.35. There was no statistical signiﬁcant difference of the ratio between immediate post-euthanasia and at other interval time of death. AllP-values were greater than 0.05.

Small amount of gas was present in the thoracic esophagus of three cadavers immediately after euthanasia. There was slight increase in the amount of esophageal gas at 8 h, 16 h and 24 h post-euthanasia. The extra thoracic structures (excluding the abdomen) were normal immediately and at 8 h after euthanasia. Gas in the

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perforating branch of the internal thoracic artery and dorsal branch of the intercostal artery was seen at 16 h post-euthanasia in four cadavers. Severe subcutaneous emphysema was present in one cadaver. Severe subcutaneous emphysema developed in two

cadavers at 24 h post-euthanasia. Previously seen gas in the branches of internal thoracic artery and intercostal artery remain unchanged. Vacuum phenomenon of the scapulohumeral joints was seen in four cadavers; two at 16 and 24 h post-euthanasia,

Fig. 1.Serial of right lateral thoracic radiographs of a dog. (A) Immediately after euthanasia. There are no abnormalities of the thorax observed. (B) 8 h after euthanasia. There is slight increase in gas in the cranial thoracic esophagus. (C) 16 h after euthanasia. There is increased amount of gas in the esophagus. Gas is now present in the pleural cavity, cranial mediastinum, right ventricle, main pulmonary artery, and also coronary arteries. There is alveolar pattern of the caudodorsal lung ﬁeld. Note that intrahepatic gas in tubular branching pattern and small amount of peritoneal gas against the diaphragm is present. (D) 24 h after euthanasia. There is further increment in the amount of gas in all structures seen at 16 h after euthanasia. Intracardial gas of the right and left ventricle and left atrium is very prominent now. Gas is also present in the caudal vena cava. There is presence of intracapsular gas in the scapulohumeral joints. Note that there is increased amount of free peritoneal gas and there is vesicular pattern of the intrahepatic gas. (E) This is the left lateral radiograph of the same cadaver at 24 h post-euthanasia. There is shifting of the intracardial gas. Less gas is present in the right ventricle and gas in the left ventricle is extending into the ascending aorta.

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respectively (Fig. 3). No evidence of secondary degenerative joint disease was detected in all scapulohumeral joints.

3.3. In situ gross necropsy ﬁndings

An in situ gross pathological examination was conducted 24 h post-euthanasia on all the cadavers with emphasis on the thoracic cavity. No anatomical abnormalities were seen in the thoracic cavity of all dogs. Moderate to severe putrefaction of the lungs, esophagus and heart was observed in all dogs after 24 h of death. Diaphragm was intact and considerable amount of yellow to red ﬂuid was present in the thoracic cavity. Lungs were collapsed, congested and partly hemorrhagic which is typical of decomposed lungs. Speciﬁc cause of lung or heart pathology could not be concluded because of the ongoing decomposition process.

4. Discussion

The physical examination performed confirmed that all dogs were healthy without apparent disease prior to euthanasia. The slight leukocytosis observed in three dogs could merely be due to the immunological response towards boarding and transportation stress prior to blood collection. Since other parameters tested were within normal limits, we excluded possible causes for infection or septicemia. This is an important exclusion because in septicemic conditions, body decomposition can be accelerated and this could affect the radiographic postmortem changes observed. All cadavers developed rigor mortis within the first 8 h of death. This made the positioning of the cadavers for radiographic procedure difficult. In human cadavers, maximum stiffness of rigor mortis developed within 6–12 h of death[20].

The initial plan for the project was to obtain the abdominal radiographs at 8 h intervals post-euthanasia until 48 h. This was not performed due to severe postmortem decomposition of the

cadavers. Decomposition is the disintegration of body tissue after death. This followed the arrest of the biochemical processes which preserve the integrity of the cellular and subcellular membranes and organelles. Two parallel processes of decomposition are autolysis (self-dissolution by body enzymes released for the disintegrating cells) and putrefaction (decomposition changes produced by the action of microorganisms)[20–21]. The project was terminated 24 h post-euthanasia because all cadavers were severely decomposed and manipulation of the cadavers was difﬁcult.

The free gas detected in the pleural cavity, mediastinum, subcutaneous tissue and blood vessels is a consequence of putrefaction[7]. Other possibility of free gas in the pleural cavity is due to escape of gas from the lungs secondary to decomposition. This was possible as there was an increased of volume of free gas at 24 h post-euthanasia with lung lobes collapsed. In humans, postmortem detection of pnuemomediastinum and soft tissue emphysema of the neck has been associated with hanging[22].

The hematology and biochemistry of the two dogs with lungs changes immediately after euthanasia were perfectly normal. Alveolar pattern of the lungs involving left hemithorax in the cadaver was most likely due to hypostatic congestion of lung secondary to lateral recumbency. This is due to only one-sided involvement, no clinical signs detected prior to euthanasia and it involved only the left hemithorax. Postmortem detection of pulmonary congestion using computed tomography in newly dead (<2 h) human cadavers was as high as 70%[17]. Although radiography was performed immediately euthanasia, there may be a 10–15 min delay between euthanasia and radiography due to handling of multiple cadavers at the same time. The degree of hypostatic congestion progressed over time and it was most prominent at 16 h post-euthanasia. As for the cadaver with mild mixed alveolar interstitial pattern at the peripheral margin of the lungs on the right side, this may be due to subclinical lung pathology such as pneumonia. However, there were no differences in the manner of progression of lungs changes compared to other cadavers.

Fig. 3.Close up view of the scapulohumeral joint of one of the cadaver at 24 h post-euthanasia. Gas is present in the scapulohumeral joint and especially distending the caudal joint capsule (white arrows).

Fig. 2.Right lateral radiograph of a dog 16 h after euthanasia. Gas ﬁlled cranial and caudal vena cava leading into the gas ﬁlled right atrium is very prominent. There is tubular gas pattern of the coronary vessels.

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Postmortem detection of gas in the cardiovascular system of human cadavers was reported. The causes could be divided into two: antemortem and postmortem. The causes that lead to antemortem gas accumulation in the heart are presence of open wound which allow the gas enter into the cardiovascular system such as gun shot wound to the head or stab wound to the neck [7]; and cardiopulmonary resuscitation which is characterized by venous chatheterization that permits possible air entry and pneumatization of dissolved gas in the blood as a result of cardiac massage[16]. Another cause of gas in the cardiovascular system is iatrogenic introduction of gas secondary to intravenous administration of contrast material[23]. The most common sites of gas accumulation are main pulmonary artery, cranial vena cava, right ventricle, subclavian or branchiocephalic vein and right atrium [23]. The postmortem cause of gas in the cardiovascular system is due to putrefaction[14,24]. In this study, all gas in the cardiovascular system is due to putrefaction as there was no trauma or surgical procedure performed prior and euthanasia and immediate eutha-nasia radiographs did not show any gas in the cardiovascular system. In humans, sub-endocardial gas was detected before the presence of intracardial gas which located in the non-dependent parts of both ventricles[25]. In this study, gas in the cardiovascular system was first detected in the right ventricle, coronary vessels, main pulmonary artery and caudal vena cava. Gas was then seen in other chambers of the heart. The differences of the findings in human cadavers and this study may be due to the difference in the interval between time of death and diagnostic imaging modalities used. The interval was not mentioned in the human cadaver study. The longer the interval, the larger amount of putrefactive gas will be produced. Gas first seen in the right ventricles and caudal vena cava in the canine cadavers may indicate that there is some degree of ante-grade movement of gas from the portal veins and hepatic veins[13]. This may also due to the left lateral recumbency of the cadavers that lead to gas accumulation in the non-dependent cardiac chamber. It is interesting to note that gas in the coronary vessels was not documented in the human cadaver study. This may be due to different degree of putrefaction of the cadavers because of longer interval between time of death and radiographic investigation. Sub-endocardial gas was not detected and it was because radiography is less sensitive compared to computed tomography to document small amount of gas in the heart.

Cardiac dilatation in human cadavers is a common postmortem change and it is regarded as a nonspecific sign of death. The change may be due to circulatory standstill and intravenous fluid administration during cardiopulmonary resuscitation prior to death leading to increase circulatory blood volume and mean blood pressure[15]. No intravenous fluid was administrated prior to euthanasia of the dogs thus there was no change in the circulatory volume and pressure leading to unchanged size of the cardiac silhouette in this study. Another cause of unchanged size of the canine cardiac silhouette may be due to the insensitivity of the method of estimating cardiac size used in the study. Future study with computed tomography may be valuable to better measure the cardiac size in canine cadavers.

The ratio of the width of the caudal vena cava to the length of 4th thoracic vertebra was used in this study to normalize the differences of the body size of the cadavers. Although there was presence of gas in the caudal vena cava, it did not cause distention. In humans, reduced size of the superior vena cava, main pulmonary artery, mean volumes of the thoracic aorta and each of the cardiac chambers was documented in cadavers with cause of death of fatal hemorrhage. However, there were no change in the size of the inferior vena cava and abdominal aorta[9]. Other studies indicate that ﬂattening of the inferior vena cava detected on computed tomography was clinically associated with hypovolemia and hypotension[26–27].

Vacuum phenomenon of joints is referred to the radiographic appearance of gas collection in the joint space [28]. This phenomenon can be created in joints radiographed under stress by distraction of opposing articular surface[29–30]. It is theorized that negative pressure created during distraction lead to gas from surrounding extracellular fluid attracted to the joint space. The gas then accumulates in the joints, filling the void created in the synovial fluid. The gas remains until the articular surfaces are re-apposed[28]. Analysis of gas aspirated from human lumbar discs with vacuum phenomenon consists of 92% nitrogen combined with oxygen, carbon dioxide and traces of other gases [31]. In human beings, it is associated with degenerative spondylolisthesis, dislocation, fracture, traumatic injury and osteonecrosis[32–35]. Vacuum phenomenon is seen frequently in the scapulohumeral joints of infants whose arms are held over the head while a chest radiographs are being exposed [28]. In dogs, the vacuum phenomenon had been detected within intervertebral discs of the cervical, thoracic and lumber spine, joint space of the sternum, and scapulohumeral joints[36–38]. The intervertebral and sternal gas accumulations were associated with other radiographic features of degeneration while the vacuum phenomenon of scapulohumeral joints was associated with osteochondrosis[37– 38]. In horses, the vacuum phenomenon was identified in normal stress-flexed carpal, metacarpophalangeal and metatarsophalan-geal joints of clinically normal horses [29–30]. This vacuum phenomenon has not been reported as a postmortem finding in both human being and animals. The authors speculate that the presence of vacuum phenomenon may be related to decomposi-tion of the body and accumuladecomposi-tion of putrefactive gas in the shoulder joints and not due to diseases or stress position of the joints. The stretching of the shoulder joints during positioning leading to vacuum phenomenon is impossible because the cadavers were stiff at the end of the project due to rigor mortis and stretching of the shoulder joints were not likely. Further more, this vacuum phenomenon was seen on lateral radiographs where there was no manual handling of the cadavers.

Postmortem radiology is becoming popular in veterinary medicine. This is due to pets becoming an important part of most families and being humanized by the owners. Interpretation of the postmortem radiographs should take into consideration the normal postmortem changes such as presence of putrefactive gas in the organs and hypostatic congestion of the lungs and should not be confused with disease process. To reduce the rate of postmortem decomposition and thus radiographic changes, cadaver should be kept at a lower ambient temperature immediately after death prior to radiographic procedure.

Acknowledgements

Supported by a grant from Veterinary Teaching Hospital, Universiti Putra Malaysia. We thank Ms. Sandy Campbell for her assistance in manuscript preparation.

References

[1] J.E. Cooper, M.E. Cooper, Introduction to Veterinary and Comparative Forensic Medicine, Blackwell Publishing, Oxford, Ames, IA, 2007.

[2] M.D. Merck, Veterinary Forensics: Animal Cruelty Investigations, Blackwell Publishing, Ames, IA, 2007.

[3] P. Saukko, B. Knight, The forensic autopsy, in: P. Saukko, B. Knight (Eds.), Knight’s Forensic Pathology, Arnold, London, New York, 2004, pp. 1–51.

[4] M.J. Thali, B.P. Kneubuehl, S.A. Bolliger, A. Christe, U. Koenigsdorfer, C. Ozdoba, E. Spielvogel, R. Dirnhofer, Forensic veterinary radiology: ballistic-radiological 3D computertomographic reconstruction of an illegal lynx shooting in Switzerland, Forensic Sci. Int. 171 (2007) 63–66.

[5] C.P. Ober, T.C. Spotswood, R. Hancock, Fatal venous air embolism in a cat with a retropharyngeal diverticulum, Vet. Radiol. Ultrasound 47 (2006) 153–158. [6] C.S. Farrow, J.P. Morgan, E.C. Story, Late term fetal death in the dog: early

(6)

[7] R. Dirnhofer, C. Jackowski, P. Vock, K. Potter, M.J. Thali, VIRTOPSY: minimally invasive, imaging-guided virtual autopsy, Radiographics 26 (2006) 1305–1333. [8] M.J. Thali, M. Braun, U. Buck, E. Aghayev, C. Jackowski, P. Vock, M. Sonnenschein, R. Dirnhofer, VIRTOPSY—scientiﬁc documentation, reconstruction and animation in forensic: individual and real 3D data based geo-metric approach including optical body/object surface and radiological CT/MRI scanning, J. Forensic Sci. 50 (2005) 428–442.

[9] E. Aghayev, M. Sonnenschein, C. Jackowski, M. Thali, U. Buck, K. Yen, S. Bolliger, R. Dirnhofer, P. Vock, Postmortem radiology of fatal hemorrhage: measurements of cross-sectional areas of major blood vessels and volumes of aorta and spleen on MDCT and volumes of heart chambers on MRI, Am. J. Roentgenol. 187 (2006) 209–215. [10] K. Yen, M. Sonnenschein, M.J. Thali, C. Ozdoba, J. Weis, K. Zwygart, E. Aghayev, C.

Jackowski, R. Dirnhofer, Postmortem multislice computed tomography and mag-netic resonance imaging of odontoid fractures, atlantoaxial distractions and ascending medullary edema, Int. J. Legal Med. 119 (2005) 129–136.

[11] E. Aghayev, M.J. Thali, M. Sonnenschein, C. Jackowski, R. Dirnhofer, P. Vock, Post-mortem tissue sampling using computed tomography guidance, Forensic Sci. Int. 166 (2007) 199–203.

[12] M.F. McKenna, J.A. Goldbogen, J. St Leger, J.A. Hildebrand, T.W. Cranford, Evalua-tion of postmortem changes in tissue structure in the bottlenose dolphin (Tursiops truncatus), Anat. Rec. (Hoboken) 290 (2007) 1023–1032.

[13] H.G. Heng, W.T. Teoh, A.R. Sheikh-Omar, Postmortem abdominal radiographic ﬁndings in feline cadavers, Vet. Radiol. Ultrasound 49 (2008) 26–29. [14] C. Jackowski, W. Schweitzer, M. Thali, K. Yen, E. Aghayev, M. Sonnenschein, P.

Vock, R. Dirnhofer, Virtopsy: postmortem imaging of the human heart in situ using MSCT and MRI, Forensic Sci. Int. 149 (2005) 11–23.

[15] S. Shiotani, M. Kohno, N. Ohashi, K. Yamazaki, H. Nakayama, K. Watanabe, Y. Itai, Dilatation of the heart on postmortem computed tomography (PMCT): compar-ison with live CT, Radiat. Med. 21 (2003) 29–35.

[16] S. Shiotani, M. Kohno, N. Ohashi, S. Atake, K. Yamazaki, H. Nakayama, Cardio-vascular gas on non-traumatic postmortem computed tomography (PMCT): the inﬂuence of cardiopulmonary resuscitation, Radiat. Med. 23 (2005) 225–229. [17] S. Shiotani, M. Kohno, N. Ohashi, K. Yamazaki, H. Nakayama, K. Watanabe, Y.

Oyake, Y. Itai, Non-traumatic postmortem computed tomographic (PMCT) ﬁnd-ings of the lung, Forensic Sci. Int. 139 (2004) 39–48.

[18] F.H. Mirza, P.A. Makhdoom, Importance of correct interpretation of postmortem artifacts in medicolegal autopsies, J. Pak. Med. Assoc. 48 (1998) 49–50. [19] J.W. Buchanan, J. Bucheler, Vertebral scale system to measure canine heart size in

radiographs, J. Am. Vet. Med. Assoc. 206 (1995) 194–199.

[20] P. Saukko, B. Knight, The pathophysiology of death, in: P. Saukko, B. Knight (Eds.), Knight’s Forensic Pathology, Arnold, London, New York, 2004, pp. 52–97. [21] J.A. Perper, Time of death and changes after death, in: W.U. Spitz (Ed.), Spitz and

Fisher’s Medicolegal Investigation of Death, Charles C Thomas, Springﬁeld, IL, 1993, pp. 14–64.

[22] E. Aghayev, K. Yen, M. Sonnenschein, C. Jackowski, M. Thali, P. Vock, R. Dirnhofer, Pneumomediastinum and soft tissue emphysema of the neck in postmortem CT and MRI; a new vital sign in hanging? Forensic Sci. Int. 153 (2005) 181–188.

[23] R. Groell, G.J. Schafﬂer, R. Rienmueller, The peripheral intravenous cannula: a cause of venous air embolism, Am. J. Med. Sci. 314 (1997) 300–302. [24] W. Keil, K. Bretschneider, D. Patzelt, I. Behning, E. Lignitz, J. Matz, Air embolism or

putrefaction gas? The diagnosis of cardiac air embolism in the cadaver, Beitr. Gerichtl. Med. 38 (1980) 395–408.

[25] C. Jackowski, M. Sonnenschein, M.J. Thali, E. Aghayev, K. Yen, R. Dirnhofer, P. Vock, Intrahepatic gas at postmortem computed tomography: forensic experience as a potential guide for in vivo trauma imaging, J. Trauma 62 (2007) 979–988. [26] R.B. Jefferey, M.P. Federle, The collapsed inferior vena cava: CT evidence of

hypovolemia, Am. J. Roentgenol. 150 (1988) 431–432.

[27] G.A. Taylor, M.E. Fallat, M.R. Eichelberger, Hypovolemic shock in children: abdominal CT manifestations, Radiology 164 (1987) 479–481.

[28] D.M. Fuiks, C.E. Grayson, Vacuum pneumoarthrography and the spontaneous occurrence of gas in the joint spaces, J. Bone Joint Surg. Am. 32 (1950) 933–938. [29] R.D. Gottschalk, R.M. Kirberger, S.L. Fourie, Vacuum phenomenon in equine carpal, metacarpophalangeal and metatarsophalangeal joints, J. S. Afr. Vet. Assoc. 70 (1999) 5–8.

[30] T.E. Specht, P.W. Poulos, M.R. Metcalf, I.D. Robertson, Vacuum phenomenon in the metatarsophalangeal joint of a horse, J. Am. Vet. Med. Assoc. 197 (1990) 749– 750.

[31] L.T. Ford, L.A. Gilula, W.A. Murphy, M. Gado, Analysis of gas in vacuum lumbar disc, Am. J. Roentgenol. 128 (1977) 1056–1057.

[32] M. Libicher, A. Appelt, I. Berger, M. Baier, P.J. Meeder, I. Grafe, K. Dafonseca, G. Noldge, C. Kasperk, The intravertebral vacuum phenomenon as speciﬁc sign of osteonecrosis in vertebral compression fractures: results from a radiological and histological study, Eur. Radiol. 17 (2007) 2248–2252.

[33] R. Ahmad, S. Annamalai, M. Radford, C. Cook, Vacuum phenomenon in a dislocated joint, Emerg. Med. J. 24 (2007) 862.

[34] D.M. Wright, D.H. Sochart, Spontaneous vacuum phenomenon in the lateral compartment of the knee associated with a lateral tibial plateau fracture, Knee 13 (2006) 42–44.

[35] P. Virtama, The vacuum phenomenon in knee- and shoulder-joints, Ann. Chir. Gynaecol. Fenn. 46 (1957) 51–56.

[36] T. Schwarz, M.R. Owen, S. Long, M. Sullivan, Vacuum disk and facet phenomenon in a dog with cauda equina syndrome, J. Am. Vet. Med. Assoc. 217 (2000) 862–864. [37] H. van Bree, Vacuum phenomenon associated with osteochondrosis of the scapulohumeral joint in dogs: 100 cases (1985–1991), J. Am. Vet. Med. Assoc. 201 (1992) 1916–1917.

[38] W.J. Weber, C.R. Berry, R.W. Kramer, Vacuum phenomenon in twelve dogs, Vet. Radiol. Ultrasound 36 (1995) 493–498.