Intrahepatic gas at postmortem computed tomography: forensic experience as a potential guide for in vivo trauma imaging

Accuracy of forensic pathologists in incorporating post-mortem CT (PMCT) in forensic death investigation

Post-mortem computed tomography (PMCT) is now performed routinely in some medical examiner's offices, and the images are typically interpreted by forensic pathologists. In this study, the question of whether pathologists appropriately identify significant PMCT findings and incorporate them into the death investigation report and the cause and manner of death (COD and MOD) statements was addressed. We retrospectively reviewed 200 cases where PMCT was performed. The cases were divided into four categories: (1) full autopsy without radiology consultation (n = 77), (2) external exam without radiology consultation (n = 79), (3) full autopsy with radiology consultation (n = 26), (4) external exam with radiology consultation (n = 18). A radiologist (not the consult radiologist) read the PMCT images, and a pathologist (not the case pathologist) reviewed the case pathologist's post-mortem examination report in tandem to determine any PMCT findings omitted from the report. Omitted findings were classified into error types according to a modified Goldman classification including Major 1: Unrecognized fatal injury or pathology that would change COD and/or MOD, and Major 2: Unrecognized fatal injury or pathology that would not change COD and/or MOD. A total of 13 Major errors were identified (6.5%), and none definitively changed the MOD. All four Major-1 errors which could change the COD were found in Category 2. Of 9 Major-2 errors, 2 occurred in Category 1, 6 occurred in Category 2, and 1 occurred in Category 4. In conclusion, forensic pathologists who routinely utilize computed tomography (CT) interpret CT images well enough to reliably certify the COD and MOD.

Forensic imaging: a powerful tool in modern forensic investigation

Forensic imaging is a non-invasive examination process during the forensic investigation. It is mainly used in forensic pathology as an adjunct to the traditional autopsy. In the past two decades, forensic imaging has been vigorously developed by forensic experts from computed tomography (CT) to multiple augmented techniques through CT and magnetic resonance imaging (MRI). The application field of forensic imaging has also been broadened as its advantages are recognised by more forensic practitioners. In addition to the forensic pathology, this technique has been used in other forensic disciplines, including forensic anthropology, forensic odontology, forensic ballistics and wildlife forensics, etc. This article reviews the development of forensic imaging as the practice and research development in different forensic disciplines based on the relevant literature analysis.

Postmortem computed tomography of gas gangrene with aortic gas in a dialysis patient

Recently, postmortem imaging is sometimes used as an alternative to conventional autopsy. However, there are few case reports of postmortem imaging of dialysis patients. Here, we report a fatal case of gas gangrene involving a 76-year-old man who underwent dialysis. He died suddenly before a diagnosis could be established. Immediately after his death, postmortem computed tomography (PMCT) revealed gas accumulation in his right upper extremity and ascending aorta. Gas gangrene progresses rapidly and may sometimes result in sudden death before it is diagnosed. In this case, PMCT findings were useful to diagnose gas gangrene. Intravascular gas is a common finding on PMCT and is generally caused by cardiopulmonary resuscitation and decomposition. However, the detection of gas in the ascending aorta by PMCT was not described previously. Moreover, Gram stain and culture of the exudate showed anaerobic Gram-positive bacilli which suggested that the gas generation in the blood was caused by Clostridia species. To the best our knowledge, this is the first report of a dialysis patient whose cause of death was determined as gas gangrene using PMCT.

Significance of intracranial gas on post-mortem computed tomography in traumatic cases in the context of medico-legal opinions

The detection of intracranial gas (ICG) in people who died due to trauma became possible once postmortem computed tomography (PMCT) became available in addition to traditional post-mortem examinations. The aim of this study was to determine the importance of ICG in the context of medico-legal opinions. We assessed 159 cases of trauma-induced death. Cadavers with pronounced signs of decomposition, open skull fractures, and after neurosurgical operations were excluded. Both PMCT findings and data from autopsy reports were analyzed. ICG was found in 38.99% (n = 62) of the cadavers, 96.77% (n = 60) of which presented with pneumocephalus (PNC) and 40.23% (n = 25) with intravascular gas (IVG). There was a strong correlation between ICG and skull fractures/brain injuries, as well as chest injuries, especially lung injuries. In 13 cases, ICG presented without skull fractures; three of these cases died as a result of stab and incised wounds to the neck and chest. The mean time between trauma and death was significantly longer in the non-ICG group than the ICG group at 2.94 days (0–48 days) and 0.01 day (0–1 day), respectively (p < 0.0001). The presence of ICG is a result of severe neck and chest injuries, including stab and incised wounds. The victims die in a very short amount of time after suffering trauma resulting in ICG. The ability to demonstrate ICG on PMCT scans can be of significance in forming medico-legal opinions.

Vital reactions - An updated overview

The question whether an injury was sustained during life or not is one of the most important subjects in forensic medicine. Therefore, vital reactions have been a main research topic in forensic medicine for a long period and many renowned forensic pathologists have devoted important papers to this field. The research area ranges from macroscopically visible organ reactions, over tissue alterations (enzyme histochemistry, later on immunohistochemistry with a wide range of enzymes and other analytes, molecular pathology) to biochemical responses to injury. Especially in the field of immunohistochemistry and molecular pathology much progress has been achieved in the last years (e.g. heat-shock-proteins or positive aquaporine3-staining in mechanical skin trauma). Furthermore, 20 years after its implementation postmortem imaging also contributes to the detection and visualization of vital signs. The aim of the present review is to provide an update on forensically relevant vital signs/vital reactions. Systemic vital reactions especially of the circulatory and respiratory system as well as local vital reactions will be addressed. Vital reactions of different organ systems will be discussed in detail regarding pathogenesis and possible postmortem evolution. Current research on immunohistochemically detectable vital reactions (heat-shock-protein expression, aquaporine3-staining in mechanical trauma of the skin) will be addressed as well as biochemical vital reactions (agonochemical stress reaction, myoglobine in electrocution death, hypoxanthine as marker of hypoxia).

Posttraumatic venous gas in the liver - a case report and review of the current literature

Background

There are numerous causes of hepatic gas formation that range from serious pathologies to incidental findings, including mesenteric infarction, liver abscess, inflammatory bowel disease or minimally invasive hepatic interventions.

Case presentation

We report a case of a 50-year-old man who was admitted to the emergency room after a car accident. The clinical examination and further diagnostics revealed a craniocerebral injury with a fracture of the skull, concomitant soft tissue lesions and subarachnoidal bleeding. Furthermore, a blunt thoracic trauma with hemopneumothorax due to rib fractures was treated with a chest tube. No obvious abdominal pathology was seen. While in the operating theatre for the surgical revision of the cranial soft tissue lesions, a femoral venous catheter was inserted without any complications. A routine ultrasound of the abdomen six hours after the trauma revealed unclear hepatic gas formation. A contrast-enhanced computer tomography (CT) scan of the abdomen was performed, and the gas formation was found to be localized within the left hepatic vein. Afterwards, there was no specific treatment of the hepatic venous gas formation, as no alterations of liver function or liver enzymes were seen. The further course of the patient was uneventful regarding the gas formation in the liver, and another ultrasound two days later revealed no further gas in the liver.

Conclusions

The placement of a femoral venous catheter is a risk factor for gas formation in liver veins. No further treatment is needed in cases with stable liver function. To rule out serious pathologies, diagnostic findings (e.g., ultrasound, CT), clinical history and underlying diseases need to be analyzed carefully after the detection of intrahepatic gas formation. With contrast-enhanced CT, the localization of the gas and its potential causes might be detectable.

Use of Postmortem Computed Tomography to Detect Bowel Obstruction and its Relationship to the Cause of Death

Bowel distension frequently indicates bowel obstruction, which is a common diagnosis in clinical radiology. Typically, symptoms and complaints lead to radiological examinations and the detection of the etiology. Untreated intestinal obstructions can lead to a fatal outcome through cardiac failure due to septic shock. Certain of these cases undergo medicolegal investigations depending on the case history, the condition of the decedent, the location of the finding, or recent visits to medical professionals. Computed tomography (CT) is a recommended method in clinical radiology for the detection of bowel obstruction, which is indicated by bowel distension and further radiological signs (eg, the whirl sign, which indicates a volvulus). Postmortem CT (PMCT) has increased worldwide, but PMCT differs from clinical CT; thus, the question of whether PMCT is also reliable for the detection of bowel obstruction in decedents or is negatively affected by postmortem modifications should be discussed. This study consists of 10 cases displaying radiological signs of bowel obstruction. Apart from bowel distension, the most common radiological signs (whirl sign, coffee bean sign, bird beak sign, and u-shape sign) are described and depicted. All decedents underwent autopsy and had a postmortem interval of less than 72 hours. Based on these cases, we assess the reliability of PMCT for detecting bowel obstruction and determining its relationship to the cause of death.

Total-body CT and MR features of postmortem change in in-hospital deaths

OBJECTIVES

To evaluate the frequency of total-body CT and MR features of postmortem change in in-hospital deaths.

MATERIALS AND METHODS

In this prospective blinded cross-sectional study, in-hospital deceased adult patients underwent total-body postmortem CT and MR followed by image-guided biopsies. The presence of PMCT and PMMR features related to postmortem change was scored retrospectively and correlated with postmortem time interval, post-resuscitation status and intensive care unit (ICU) admittance.

RESULTS

Intravascular air, pleural effusion, periportal edema, and distended intestines occurred more frequently in patients who were resuscitated compared to those who were not. Postmortem clotting was seen less often in resuscitated patients (p = 0.002). Distended intestines and loss of grey-white matter differentiation in the brain showed a significant correlation with postmortem time interval (p = 0.001, p<0.001). Hyperdense cerebral vessels, intravenous clotting, subcutaneous edema, fluid in the abdomen and internal livores of the liver were seen more in ICU patients. Longer postmortem time interval led to a significant increase in decomposition related changes (p = 0.026).

CONCLUSIONS

There is a wide variety of imaging features of postmortem change in in-hospital deaths. These imaging features vary among clinical conditions, increase with longer postmortem time interval and must be distinguished from pathologic changes.

Post mortem CT of intrahepatic gas distribution in twenty-seven victims of a flood: Patterns and timing

We reported the results of post mortem computed tomography of the liver in 27 subjects dead simultaneously during a flood. The aim of our work was to identify the different patterns of post mortem intrahepatic gas distribution and the timing of its appearance. Although post mortem CT is the method of choice for the evaluation of gas distribution, controversies exist about the first site of appearance of intrahepatic gas (portal veins versus hepatic veins) as well as the timing and steps of intrahepatic gas spreading. In each subject we performed thin slice CT scanner (Somatom Definition, Siemens) and post processing of native CT images with Minimum Intensity Projection technique. Our results show that the first site of appearance of intrahepatic gas is portal veins. Gas in hepatic veins was never seen without the presence of the gas in portal vein. Gaseous cysts in hepatic parenchyma represent a further and usually more tardive pattern of intrahepatic gas distribution. In addition, we demonstrated that differences in timing of gas spreading was statistically significative for exclusive presence of portal veins gas before 48h as well as for complete substitution of hepatic parenchyma by cysts 64h after death. In conclusion, our work shows that the CT study of postmortem intrahepatic gas distribution could be a useful complementary tool both in demonstrating the mechanism of intrahepatic gas spreading and in estimating post mortem interval.

Early time-related course of image findings in postmortem MRI: Typical findings and observer agreement in a porcine model

PURPOSE

To assess early time-related image findings in postmortem magnetic resonance imaging (MRI) and to evaluate observer agreement in a porcine model.

MATERIAL AND METHODS

Three pigs were examined by MRI at 15 different time points in the first 36h after death. Two observers independently recorded the postmortem interval (PMI) to the appearance of fluid collection (pleural space, interlobar and interlobular pulmonary fissures and hepatic interlobar fissures), gas accumulation (intrahepatic and intracardial) and blood clotting (aorta and intrahepatic venous vessels). Cohen's Kappa statistics and intraclass correlation coefficient (ICC) were used to evaluate intra- and interobserver agreement.

RESULTS

Intrahepatic gas was evident after 12, 17 and 30h. Also, intracardiac gas was present in all animals. However, no chronological appearance has been observed. Blood clotting in the hepatic vein was observed within 3min, aortic clotting with a delay of 2-12h after death. Interlobular pulmonary fluid (median PMI: 2h, range 2-2h), pleural effusion (median PMI: 10.5h, range 9-12h) and hepatic interlobar fissure fluid (median PMI: 11.5h, range 11-12h) displayed a chronological appearance pattern. Qualitative and quantitative detection of most postmortem findings showed excellent intra- and interobserver agreement with Kappa values>0.8 or ICC>0.75.

CONCLUSION

Pulmonary and hepatic fissural fluid collection as well as intravasal gas accumulation are early time-related image findings in postmortem MRI. The chronological appearance of these findings can be assessed with excellent observer agreement in a porcine model.

Comparison of the cardiothoracic ratio between postmortem and antemortem computed tomography

As postmortem imaging has gained prominence as a supplement to traditional autopsy, it is important to understand the normal postmortem changes to enable the accurate evaluation of postmortem imaging. No studies have evaluated the postmortem changes in cardiothoracic ratio (CTR) compared with antemortem images in the same subjects. We studied 147 consecutive subjects who underwent antemortem and postmortem CT, and autopsy. Postmortem CT was performed <23h after death and was followed by autopsy. The subjects were divided into three groups: normal heart, old myocardial infarction, and CPR-treated hearts. CTR was compared between antemortem and postmortem CT using paired t tests, which revealed that the CTR was greater on postmortem CT than on antemortem CT in all groups (mean CTR: 0.53±0.06vs. 0.50±0.06, respectively; P<0.01). Sex, age, time elapsed since death, and the causes of death were examined as potential confounding factors for the postmortem changes in CTR, but no significant associations were found. Receiver-operating characteristic (ROC) curves were used to determine CTR values for cardiomegaly, which was defined according to the autopsy weight of the heart. The area under the ROC curve was 0.71 (95% confidence interval 0.63-0.79). The CTR threshold of 0.54 identified cardiomegaly with the greatest accuracy, compared with the general threshold of 0.50. In conclusion, the CT-determined CTR increases after death, irrespective of the heart's condition. We should be cautious of overdiagnosis of cardiomegaly on postmortem CT, and new criteria for interpreting cardiomegaly on postmortem CTR are needed.

[The foreign experience with the application of the modern radiodiagnostic methods for the estimation of prescription of death coming and time of infliction of injury]

We undertook the analysis of the foreign publications concerning the application of the modern radiodiagnostic methods (including MSCT- and MRI-visualization) with reference to the solution of the traditional problems facing forensic medical expertise, such as the estimation of prescription of death coming and time of infliction of injury in the dead bodies. Both advantages and disadvantages of postmortem visualization of the corpses of adult subjects are discussed taking into consideration the period of time that elapsed between the death and the onset of the study as well as the character of the injuries. It was shown that the examination of the corpses using the up-to-date methods of radiodiagnostics prior to autopsy makes it possible for morphologists, jointly with radiologists, to identify, to see in the new light, and to evaluate the number of charges in the dead body, such as the alteration of the blood cell sedimentation rate, the formation of postmortem hypostases in the internal organs, the hardening of the walls of aorta and major blood vessels, right heart dilatation, gradual smoothing of the borderline between grey and white matter of the brain. Virtual autopsy can be useful , even for the study of such long-term processes in the corpses as putrefaction, saponification, mummification, and peat tanning. Moreover, this technique may be instrumental in the elucidation of the specific features of topographic-anatomical relationships between individual 'tissues and organs, detection of the concealed lesions, and a variety of pathological changes. Postmortem visualization allows for the quantitative evaluation of the severity of these transformations and the preliminary estimation of prescription of death coming. Also, radiodiagnostic methods can be employed to reliably visualize and measure various hemorrhagic events (from the density of such ones as liquid and clotted blood) in the tissues surrounding the fractures, in body cavities, and internal organs as well as to establish the facts of inter-vital aspiration of blood, alimentary masses, liquid and solid foreign bodies penetrating into the upper sections of the respiratory and gastrointestinal tracts as the consequence f an injury. It is concluded that the postmortem visualization techniques employed to estimate prescription of death coming and time of infliction of injury as well as other complicated problems facing forensic medical expertize need the further scientifically based development.

Evaluation of post-mortem lateral cerebral ventricle changes using sequential scans during post-mortem computed tomography

In the present study, we evaluated post-mortem lateral cerebral ventricle (LCV) changes using computed tomography (CT). Subsequent periodical CT scans termed “sequential scans” were obtained for three cadavers. The first scan was performed immediately after the body was transferred from the emergency room to the institute of legal medicine. Sequential scans were obtained and evaluated for 24 h at maximum. The time of death had been determined in the emergency room. The sequential scans enabled us to observe periodical post-mortem changes in CT images. The series of continuous LCV images obtained up to 24 h (two cases)/16 h (1 case) after death was evaluated. The average Hounsfield units (HU) within the LCVs progressively increased, and LCV volume progressively decreased over time. The HU in the cerebrospinal fluid (CSF) increased at an individual rate proportional to the post-mortem interval (PMI). Thus, an early longitudinal radiodensity change in the CSF could be potential indicator of post-mortem interval (PMI). Sequential imaging scans reveal post-mortem changes in the CSF space which may reflect post-mortem brain alterations. Further studies are needed to evaluate the proposed CSF change markers in correlation with other validated PMI indicators.

Postmortem Changes as Documented in Postmortem Computed Tomography Scans

The benefits and uses of postmortem computed tomography (PMCT) have been well documented in the forensic pathology and radiology literature in recent years and research into its utility continue in earnest. Opinions and policies regarding who actually interprets the PMCT scans vary between institutions, but in general, scans will be read by a forensic pathologist, a clinical radiologist, or a clinical radiologist with a special interest or training in postmortem imaging. Differences between clinical computed tomography scans and PMCT scans have been well documented and knowledge of these differences, typically those due to postmortem changes, is essential to the reader of the PMCT scan so as to minimize the risk of misinterpretation and, potentially, misdiagnoses.

Comparison of volume and attenuation of the spleen between postmortem and antemortem computed tomography

OBJECTIVES

The purpose of this study is to compare the postmortem changes in computed tomography (CT) findings between normal spleen, splenic infarct, and splenic tumor infiltration.

METHODS

The institutional review board approved this study, and informed consent was obtained from the next of kin. We studied 63 consecutive subjects who underwent antemortem CT, postmortem CT, and autopsy between February 2012 and December 2013. Postmortem CT was performed within 1678 min after death and was followed by pathological studies. The subjects were divided into three groups based on the pathological findings: normal, splenic infarct, and splenic tumor infiltration. The volume and attenuation of the spleen were compared between antemortem and postmortem CT using paired t tests. Gender, age, time elapsed since death, and the causes of death were examined as potential confounding factors of the postmortem changes in volume and attenuation.

RESULTS

In all groups, the spleen decreased in volume and attenuation increased on postmortem CT compared with antemortem CT. The postmortem changes in spleen volume and attenuation were not significantly associated with sex, age, time elapsed since death, or causes of death.

CONCLUSIONS

Spleen volume decreased and attenuation increased on postmortem CT compared with antemortem CT in subjects with a normal spleen, splenic infarct, or splenic tumor infiltration. These results should caution us against underestimating the significance of splenomegaly on postmortem CT, misinterpreting reduced splenic volume as the presence of hypovolemic or distributive shock in the subject while alive, and confusing postmortem splenic hyperattenuation with diseases characterized by this finding.

Freezing effect on brain density in postmortem CT

Two 60-year-old males were found at their homes whose bodies had deteriorated due to putrefaction. To prevent worm invasion and minimize deterioration, dry ice was used prior to the autopsy investigation. Prior to autopsy, postmortem CT demonstrated a decreased density in brain parenchyma at the dry-iced side, and autopsy revealed deteriorated brain parenchyma with frozen effect (presented like sherbet). Moreover, the deteriorated cerebral parenchyma maintained their structure and they were evaluated by cutting. When lower CT density presents in postmortem CT, the freezing effect may need to be considered and the physician should evaluate the cadaver's postmortem condition to prevent misdiagnoses.

Common Postmortem Computed Tomography Findings Following Atraumatic Death: Differentiation between Normal Postmortem Changes and Pathologic Lesions

Computed tomography (CT) is widely used in postmortem investigations as an adjunct to the traditional autopsy in forensic medicine. To date, several studies have described postmortem CT findings as being caused by normal postmortem changes. However, on interpretation, postmortem CT findings that are seemingly due to normal postmortem changes initially, may not have been mere postmortem artifacts. In this pictorial essay, we describe the common postmortem CT findings in cases of atraumatic in-hospital death and describe the diagnostic pitfalls of normal postmortem changes that can mimic real pathologic lesions.

Normal pediatric postmortem CT appearances

Postmortem radiology is a rapidly developing specialty that is increasingly used as an adjunct to or substitute for conventional autopsy. The goal is to find patterns of disease and possibly the cause of death. Postmortem CT images bring to light processes of decomposition most radiologists are unfamiliar with. These postmortem changes, such as the formation of gas and edema, should not be mistaken for pathological processes that occur in living persons. In this review we discuss the normal postmortem thoraco-abdominal changes and how these appear on CT images, as well as how to differentiate these findings from those of pathological processes.

Virtopsy Computed Tomography in Trauma: Normal Postmortem Changes and Pathologic Spectrum of Findings

Virtopsy or virtual autopsy is an emerging technique, developed to supplement traditional forensic autopsy. Virtopsy can be done by using imaging techniques such as computed tomography (CT) and magnetic resonance imaging. Virtopsy CT comprises a pan-body noncontrast CT scan obtained after death. Virtopsy CT is useful in trauma cases as it can provide an overview of injuries sustained by the victim; detect craniofacial, cerebral, thoracic, and osseous injuries; and suggest putative causes of death. This can reduce the time taken for forensic autopsy and sometimes obviate the need for a forensic autopsy. However, virtopsy CT reporting is not exactly synonymous with interpreting antemortem contrast-enhanced CT images as postmortem decompositional changes also occur. Awareness of imaging appearances of both postmortem putrefactive changes and pathologic findings is essential to avoid errors in interpretation and enable estimation of cause of death in patients with trauma.

Fluid in the airway of nontraumatic death on postmortem computed tomography: relationship with pleural effusion and postmortem elapsed time

To evaluate radiographic features of endotracheal/endobronchial fluid in the airway (FA) observed on postmortem computed tomography (PMCT). We studied 164 subjects who died at our hospital between April 2009 and September 2012. Fluid in the airway was considered positive when fluid was identified in the lumen of 1 of the 2 main bronchi in continuity with a segmental bronchus. Pleural effusion and atelectasis/consolidation of the lung lower lobes were also evaluated. Fluid in the airway was observed in 60 (71%) of 84 subjects with unilateral or bilateral pleural effusion, and in 44 (55%) of 80 subjects without pleural effusion (P = 0.029). Of the latter, 41 (93%) had atelectasis/consolidation of the lower lung lobes. Among subjects without pleural effusion, average times after death to PMCT of subjects with and without FA were 501 and 314 minutes, respectively (P = 0.01). Time-course analysis showed that cases with FA on PMCT largely correlated with time after death (R = 0.7966). Fluid in the airway is frequently observed on PMCT in subjects with pleural effusion or atelectasis/consolidation of the lung. No FA in subjects without pleural effusion correlated to shorter times after death. In addition, FA frequency on PMCT increased over time after death.

Differences between postmortem computed tomography and conventional autopsy in a stabbing murder case

OBJECTIVE

The aim of the present work is to analyze the differences and similarities between the elements of a conventional autopsy and images obtained from postmortem computed tomography in a case of a homicide stab wound.

METHOD

Comparison between the findings of different methods: autopsy and postmortem computed tomography.

RESULTS

In some aspects, autopsy is still superior to imaging, especially in relation to external examination and the description of lesion vitality. However, the findings of gas embolism, pneumothorax and pulmonary emphysema and the relationship between the internal path of the instrument of aggression and the entry wound are better demonstrated by postmortem computed tomography.

CONCLUSIONS

Although multislice computed tomography has greater accuracy than autopsy, we believe that the conventional autopsy method is fundamental for providing evidence in criminal investigations.

Comparison of attenuation of striated muscle between postmortem and antemortem computed tomography: results of a longitudinal study

Objective

We evaluated the postmortem changes of striated muscle by comparing computed tomography (CT) images obtained postmortem and antemortem in the same patients.

Materials and Methods

We studied 33 consecutive patients who underwent antemortem CT, postmortem CT, and pathological autopsy in our tertiary care hospital between April 2009 and December 2010. Postmortem CT was performed within 20 h after death and was followed by pathological autopsy. Pathological autopsy confirmed the absence of muscular diseases such as amyotrophic lateral sclerosis, muscular dystrophy, myositis, and myasthenia, in all of the patients. The CT attenuation values of four cardiac muscle sites (anterior wall of the left ventricle, left ventricular free wall, posterior wall of the left ventricle, and the ventricular septum) and two skeletal muscle sites (the pectoralis major muscle and the erector spinae muscle) were compared between antemortem and postmortem CT using paired t test.

Results

Striated muscle had significantly greater attenuation on postmortem CT than on antemortem CT (P<0.001) in all six tissue sites. No significant association was found between postmortem change in the CT attenuation of striated muscle and gender, age, or elapsed time since death.

Conclusion

This is the first longitudinal study to show hyperattenuation of striated muscle on postmortem CT images compared with antemortem CT images in the same patients.

Greater thickness of the aortic wall on postmortem computed tomography compared with antemortem computed tomography: the first longitudinal study

OBJECTIVES

To evaluate postmortem changes of the aorta on postmortem computed tomography (CT) in comparison with those on antemortem CT obtained in the same patients.

MATERIALS AND METHODS

We studied 57 consecutive patients who had undergone antemortem CT, postmortem CT, and pathological autopsy in our tertiary care hospital between April 2009 and December 2010. Postmortem CT was performed within 20 h after death, followed by pathological autopsy. Pathological autopsy confirmed the absence of cardiovascular disease such as aortic aneurysm, aortic dissection, or Marfan syndrome in all patients. Aortic wall thickness and aortic cross-sectional areas were measured on both antemortem CT and postmortem CT. Difference in aortic wall thickness between antemortem CT with and without contrast medium, and between antemortem CT and postmortem CT, and in cross-sectional area of the aortic wall between antemortem CT and postmortem CT was evaluated statistically.

RESULTS

No significant difference in aortic wall thickness was observed on antemortem CT in comparison of contrasted and non-contrasted images. The aortic wall was significantly thicker on postmortem CT than on antemortem CT (p < 0.0001). No significant difference in cross-sectional area of the aortic wall was observed between antemortem CT and postmortem CT measurements.

CONCLUSION

This is the first longitudinal study to confirm greater thickness of the aortic wall on postmortem images compared with antemortem images in the same patients and to show no change in cross-sectional area of the aortic wall between before and after death.

Heart wall is thicker on postmortem computed tomography than on antemortem [corrected] computed tomography: the first longitudinal study

Objective

To evaluate the postmortem changes of the heart wall on postmortem (PM) computed tomography (CT) in comparison with those on ante mortem CT (AMCT), and in comparison with the pathological findings, obtained in the same patients.

Materials and Methods

We studied 57 consecutive patients who had undergone AMCT, PMCT, and pathological autopsy in our tertiary care hospital between April 2009 and December 2010. PMCT was performed within 20 hours after death, followed by pathological autopsy. The cardiac chambers were measured at five sites on both AMCT and PMCT by two board-certified radiologists who were not provided with clinical information. The differences in heart wall thickness between AMCT with and without contrast medium, between AMCT and PMCT, and between PMCT and pathological anatomy were evaluated statistically. Confounding factors of postmortem change such as gender, presence of arteriosclerosis, the organ related to cause of death, age, and elapsed time since death were examined statistically.

Results

No significant differences were observed on AMCT in comparison of contrasted and non-contrasted images. The heart wall was significantly thicker on PMCT than on AMCT (p < 0.0001) at all five measurement sites. The heart wall was significantly thicker on PMCT than on pathology specimens when measured in accordance with pathological standard mensuration. However, no significant difference was observed between PMCT measurements and those of pathology specimens at any site when the papillary muscles and epicardial fat were included. No significant association was found between postmortem change in heart wall thickness and gender, presence of arteriosclerosis, the organ related to cause of death, age, or elapsed time since death.

Conclusion

This is the first longitudinal study to confirm greater thickness of heart wall on postmortem images compared with ante mortem images, in the same patients. Furthermore, the postmortem changes on CT were supported by the pathological findings.

Vascular measurement changes observed using postmortem computed tomography

PURPOSE

Postmortem vascular changes were quantitatively analyzed in the aorta and vena cava and compared with antemortem findings as a basis for distinguishing between normal postmortem changes and pathological changes.

MATERIALS AND METHODS

Whole-body computed tomography (CT) was performed on 12 individuals before and after death. The scans, performed at seven levels (five for the aorta, two for the vena cava) within the vasculature, allowed various measurements to be made on the same individual before and after death.

RESULTS

Postmortem long-axis diameter, short-axis diameter, and the square of the radius of the aorta were 79.2-85.0 % (mean 81.3 %), 55.6-80.0 % (68.0 %), and 48.5-71.4 % (60.8 %) of the antemortem measurements, respectively. The ante- and postmortem measurements of the long and short axes and the caliber of the aorta were statistically different (p < 0.05). The superior vena cava (SVC) was increased in size: the short-axis diameter and the square of the radius were both statistically different after death. None of the measured parameters of the inferior vena cava (IVC) changed significantly following death.

CONCLUSION

In postmortem images, the aortic diameter decreased and changes in the size and shape of the SVC were noted. The IVC did not exhibit significant postmortem changes.

Gas at postmortem computed tomography--an evaluation of 73 non-putrefied trauma and non-trauma cases

Postmortem computed tomography (PMCT) has become an important complement in investigating forensic cases allowing an accurate detection of gas accumulations. The present study investigated the presence and distribution of gas in a large number of non-putrefied cases of traumatic and non-traumatic deaths. Furthermore the possibility of pneumobilia secondary to blunt abdominal trauma was studied. Retrospectively, 73 cases, underwent a whole-body PMCT prior to autopsy. These were divided into four groups: penetrating trauma (20 gunshot cases, 13 stabbing cases), blunt abdominal trauma (20 cases) and a control group of 20 non-trauma cases. Exclusion criteria were visible signs of decomposition. Each group was screened for gas accumulations in the vascular system, internal organs, soft tissues and body cavities. Gas accumulations were present in 98% of the trauma cases, compared to 80% of the control group. The most affected structures and/or organs in the trauma group were soft tissues, vessels and the liver. In most cases of the trauma group gas was associated with open injuries and lacerations of vessels. Furthermore, in the gunshot group gas was frequently seen in the intracranial cavity. Pneumobilia occurred in one case of the blunt trauma group; in that control group gas was also seen, but less frequently. Gas accumulation showed a strong association with traumatic events, but even the majority of non-trauma cases showed gas accumulations. Despite the exclusion of cases with visible decomposition signs, a putrefactive origin of gas was assumed in some cases. Gas accumulations are a frequent finding in PMCT with a higher incidence in (open) trauma cases. Even though a differentiation between putrefactive and traumatic gas accumulations is still difficult, knowledge of the circumstance surrounding the case may help identify the origin of gas.

Appearance of gas collections after scuba diving death: a computed tomography study in a porcine model

INTRODUCTION

Postmortem computed tomography can easily demonstrate gas collections after diving accidents. Thus, it is often used to support the diagnosis of air embolism secondary to barotrauma. However, many other phenomenons (putrefaction, resuscitation maneuvers, and postmortem tissue offgassing) can also cause postmortem gas effusions and lead to a wrong diagnosis of barotrauma.

OBJECTIVES

The aim of this study is to determine topography and time of onset of postmortem gas collections respectively due to putrefaction, resuscitation maneuvers, and tissue offgassing.

MATERIALS AND METHODS

A controlled experimental study was conducted on nine pigs. Three groups of three pigs were studied postmortem by CT from H0 to H24: one control group of nonresuscitated nondivers, one group of divers exposed premortem to an absolute maximal pressure of 5 b for 16 min followed by decompression procedures, and one group of nondivers resuscitated by manual ventilation and thoracic compression for 20 min. The study of intravascular gas was conducted using CT scan and correlated with the results of the autopsy.

RESULTS

The CT scan reveals that, starting 3 h after death, a substantial amount of gas is observed in the venous and arterial systems in the group of divers. Arterial gas appears 24 h after death for the resuscitated group and is absent for the first 24 h for the control group. Concerning the putrefaction gas, this provokes intravenous and portal gas collections starting 6 h after death. Subcutaneous emphysema was observed in two of the three animals from the resuscitated group, corresponding to the thoracic compression areas.

CONCLUSION

In fatal scuba diving accidents, offgassing appears early (starting from the first hour after death) in the venous system then spreads to the arterial system after about 3 h. The presence of intra-arterial gas is therefore not specific to barotrauma. To affirm a death by barotrauma followed by a gas embolism, a postmortem scanner should be conducted very early. Subcutaneous emphysema should not be mistaken as diagnostic criteria of barotrauma because it can be caused by the resuscitation maneuvers.

Postmortem 24-h interval computed tomography findings on intrahepatic gas development and changes of liver parenchyma radiopacity

PURPOSE

The purpose of this study was to assess and analyze the development of intrahepatic gas and its distribution over time as well as radiopacity changes of the liver parenchyma after non-traumatic death during a period of 24h using postmortem computed tomography (PMCT).

MATERIALS AND METHODS

Five male corpses (age range 24-64 yrs) who had died for any other reason than trauma were enrolled in this study. Whole body multi detector row computed tomography (MDCT) scans (Brilliance 64-channel, Philips, Amsterdam, NL) were performed for 24 h with one examination per hour. At an average of 6h after the corpses were found on scene the first CT-exam took place. For the analysis of the intrahepatic gas development and distribution within 24h after death the liver was virtually divided into four parts. Each examination was analyzed for gas bubbles and the possible increase over time using a semiquantitative/visual assessment employing a four-grade scale. The changes of the radiopacity of the liver parenchyma were assessed in a similar way. In each of the four parts of the liver three regions of interest of the same size were placed and recorded over time. Three radiologists and one coroner independently performed the analysis of the gas development and radiopacity changes.

RESULTS

In two corpses the amount of gas and its distribution did not change over the observation period whereas in the other three corpses the gas content increased within the first four to seven hours and was most pronounced in the left liver lobe and least in the right posterior liver lobe. In all five corpses the radiopacity of the liver parenchyma did not change significantly over time with the highest radiopacity in the right posterior liver lobe. Good interobserver reliability concerning the assessment of intrahepatic gas accumulation was found.

DISCUSSION

Our results indicate that PMCT is useful to detect intrahepatic gas. However, several reasons for these findings besides putrefaction e.g. trauma, resuscitation exist. For an elucidation of the exact causation of the gas accumulation further studies are required with longer postmortem examination times (24-72 h) to detect more pronounced changes of gas and organ radiopacity but also an earlier start of examination after death is desirable. Moreover, it has to be elucidated whether other organs exhibit a similar behavior and how temperature of the CT-room and the body impacts on these parameters.

Intravascular gas distribution in the upper abdomen of non-traumatic in-hospital death cases on postmortem computed tomography

OBJECTIVES

To investigate the occurrence of intravascular gas in the liver, kidneys, spleen, and pancreas by postmortem computed tomography (PMCT) in cases of non-traumatic in-hospital deaths and elucidate the relationship between the PMCT data and clinical information or autopsy results.

METHODS

The study included 45 cadavers of patients who died while receiving treatment in our academic tertiary-care hospital between April and December 2009. All subjects underwent PMCT and conventional autopsy. The appearance of postmortem gas in the liver, kidney, spleen, and pancreas was assessed using PMCT and scored using a subjective scale (liver, L0-L3; kidney, K0-K2; spleen, S0-S1; and pancreas, P0-P1), and the distribution of gases in the vessels of the liver (arteries, veins, and portal veins) was analyzed. The relationship between the gas score and time elapsed since death, cardiopulmonary resuscitation (CPR), administration of antibiotics, a history of bacteremia, or cause of death was assessed statistically.

RESULTS

Positive correlations were found between administration of CPR and liver and kidney gas scores (P=0.008 and 0.002, respectively), but not with spleen and pancreas gas (P=0.291 and 0.535, respectively). No significant relationship between distribution of gas in the vessels of the liver and CPR was found. No other significant correlations between gas and any of the other parameters described above were found. While significant correlations were detected in no-CPR cases between liver gas, kidney gas, spleen gas, and pancreas gas (P<0.001 for all six combinations), no correlation between these parameters was detected in the CPR cases.

CONCLUSIONS

The present study was the first statistical analysis of intravascular gas in the liver, kidneys, spleen, and pancreas by using PMCT in non-traumatic in-hospital death cases. The results showed that PMCT in the presence and absence of CPR reveals differences in intraorgan gas distribution. In addition, the detection of intraorgan gas on PMCT cannot be used to predict time elapsed since death, and it is not affected by the administration of antibiotics, a history of bacteremia, and cause of death. Awareness of these postmortem changes is important for the accurate interpretation of PMCT results.

Intravascular gas in multiple organs detected by postmortem computed tomography: effect of prolonged cardiopulmonary resuscitation on organ damage in patients with cardiopulmonary arrest

A 76-year-old woman was found in cardiopulmonary arrest with her head submerged in water in a bathtub. Despite cardiopulmonary resuscitation (CPR) for over 1 h by professional emergency technicians and medical doctors, the patient died. Postmortem computed tomography revealed not only pulmonary edema associated with drowning but also the presence of intravascular gas in the pulmonary artery, liver, kidneys, heart (right ventricle), and brain. It was speculated that intravascular gas was generated and spread to multiple organs during CPR procedures via the alimentary tract and lungs, which had been damaged by ischemia after cardiopulmonary arrest. Prolonged CPR procedures may involve the risk of additional organ damage and systemic air emboli.

Quantitative analysis of intracranial hypostasis: comparison of early postmortem and antemortem CT findings

OBJECTIVE

The purpose of this study was to quantitatively analyze postmortem hypostasis in the intracranial venous sinus on head CT scans compared with the antemortem CT findings in the same patients with the aim of evaluating sedimentation in the heart and great vessels.

MATERIALS AND METHODS

A total of 50 patients on whom head CT was performed before and after death were enrolled. Attenuation in the dorsal part of the superior sagittal sinus was measured at the level of the basal ganglia on both antemortem and postmortem CT scans. Increased attenuation in the transverse sinus and cerebellar tentorium and sedimentation in the heart and great vessels were evaluated visually.

RESULTS

Attenuation in the dorsal part of the superior sagittal sinus increased significantly (p < 0.0001) between antemortem (42.77 ± 6.23 HU) and postmortem (49.72 ± 10.58 HU) CT in 80% of cases. Increased attenuation of the transverse sinus or cerebellar tentorium was observed in 48% of cases and sedimentation in the heart or great vessels in 62% of cases. Increased attenuation in the superior sagittal sinus was clearly evident in patients with sedimentation in the heart or great vessels (antemortem, 43.81 ± 6.17 HU; postmortem, 54.65 ± 8.51 HU) compared with the patients without evidence of sedimentation (antemortem, 41.06 ± 6.10 HU; postmortem, 41.66 ± 8.57 HU) (p < 0.0001).

CONCLUSION

Intracranial hypostasis is a common postmortem CT finding. Radiologists and physicians who interpret postmortem neurologic images should be aware of intracranial hypostasis and differentiate this phenomenon from intracranial hemorrhage.

Clinical radiology and postmortem imaging (Virtopsy) are not the same: Specific and unspecific postmortem signs

The aim of this article is to disclose the characteristics of postmortem forensic imaging; give an overview of the several possible findings in postmortem imaging, which are uncommon or new to clinical radiologists; and discuss the possible pitfalls. Unspecific postmortem signs are enlisted and specific signs shall be presented, which are typical for one cause of death. Unspecific signs. Livor mortis may not only be seen from the outside, but also inside the body in the lungs: in chest CT internal livor mortis appear as ground glass opacity in the dependent lower lobes. The aortic wall is often hyperdense in postmortem CT due to wall contraction and loss of luminal pressure. Gas bubbles are very common postmortem due to systemic gas embolism after major open trauma, artificial respiration or initial decomposition; in particular putrefaction produces gas bubbles globally. Specific signs. Intracranial bleeding is hyperattenuating both in radiology and in postmortem imaging. Signs of strangulation are hemorrhage in the soft tissue of the neck like skin, subcutaneous tissue, platysma muscle and lymph nodes. The "vanishing" aorta is indicative for exsanguination. Fluid in the airways with mosaic lung densities and emphysema (aquosum) is typical for fresh-water drowning.

Gas in portal circulation and pneumatosis cystoides intestinalis during chemotherapy for advanced rectal cancer

OBJECTIVES

Acute abdominal symptoms with CT scan evidence of intramural gas in bowel walls (pneumatosis cystoides intestinalis, PCI) and of gas in the portal venous blood (PBG) in patients undergoing chemotherapy may represent a worrisome picture, suggestive of bowel necrosis. This picture remains a major clinical clue and the reporting of new cases may help to share awareness and experience on management. We describe a patient with acute abdominal symptoms and evidence of PCI with PBG under cetuximab, oxaliplatin, tegafur-uracil and folinic acid chemotherapy for metastatic adenocarcinoma of the rectosigmoid junction.

METHODS

After admission for mucositis with diarrhea and profound dehydration, and subsequent emergency laparotomy for derotation of an intestinal volvulus, on the tenth postoperative day the patient developed fever and abdominal pain, with CT scan evidence of PCI with PBG. The exam of the abdomen did not suggest major problems requiring emergency surgery, and antibiotic treatment with close monitoring were performed, followed by rapid improvement.

RESULTS

Twelve days later, after resumption of oral diet, the patient unexpectedly suffered a spontaneous jejunal microperforation, requiring emergency laparotomy and bowel resection. Pathology showed that the perforation was within an area of ulceration involving the inner superficial layer of the bowel. Subsequently recovery was normal and at present, after 15 months, the patient is well and continuing chemotherapy.

CONCLUSIONS

This is probably the first report of PCI with PBG related to intestinal toxicity during cetuximab, oxaliplatin, tegafur-uracil and folinic acid chemotherapy in a patient with advanced rectal carcinoma, followed by delayed small bowel perforation. It provides an example of the challenges involved in the management of this type of patient.

Intrahepatic gas at postmortem multislice computed tomography in cases of nontraumatic death

PURPOSE

The purpose of this study was to investigate the cause and significance of intrahepatic gas (IHG).

MATERIALS AND METHODS

There were 208 nontraumatically deceased individuals retrospectively investigated concerning the occurrence and location of IHG by postmortem multislice computed tomography (MSCT) imaging. The location of IHG was graded on a scale from 0 to 3: 0, no gas; 1, gas only in the left lobe; 2, gas in the left lobe and anterior segment of the right lobe; 3, gas in the left lobe and the anterior and posterior segments of the right lobe). We also assessed and noted the occurrence of intestinal distention, airway management, the interval between cardiopulmonary arrest (CPA) and subsequent examination, and the postmortem interval.

RESULTS

IHG was found in 66 cases (31.7%): grade 1, 15 (7.2%); grade 2, 21 (10.1%); grade 3, 30 (14.4%). The presence of IHG was strongly related to intestinal distention and the period between the time of CPA and the examination.

CONCLUSION

IHG is a frequent finding on postmortem CT in cases of nontraumatic death. The presence of IHG is related to intestinal distention and the interval between the time of CPA and examination.

Progressive gas formation in a deceased person during mortuary storage demonstrated on computed tomography

We report the case of an 82-year-old woman with a past history of diabetes mellitus who died following blunt head injury sustained in a fall resulting in an acute subdural hematoma. Serial postmortem CT scans of the chest and abdomen performed over a 3-day period demonstrated progressive intra-hepatic and intra-cardiac gas formation whilst the deceased was stored in a standard mortuary refrigerator at a nominated temperature of 4 degrees C. Measured mortuary refrigerator temperatures over a 7 day period showed statistically significant day to day variability in temperatures above 4 degrees C as well as variations in temperature depending on location within the refrigerator space. In the absence of other known factors associated with such gas formation, putrefaction seems the likely cause despite a lack of obvious external features. This phenomenon must therefore be taken into account when interpreting the presence of visceral gas on postmortem CT and relating such gas to the cause of death.

Post-mortem radiology--a new sub-speciality?

Computed tomography (CT) and magnetic resonance imaging (MRI) examinations of deceased individuals are increasingly being utilized in the field of forensic pathology. However, there are differences in the interpretation of post-mortem and clinical imaging. Radiologists with only occasional experience in post-mortem imaging are at risk of misinterpreting the findings if they rely solely on clinical experience. Radiological specialists working in a co-operative environment with pathologists are pivotal in the understanding of post-mortem CT and MRI, and its appropriate integration into the autopsy. This has spawned a novel subspecialty called post-mortem radiology or necro-radiology (radiology of the deceased). In the future it is likely that whole-body CT will be incorporated into the routine forensic autopsy due its ability to accurately detect and localise abnormalities commonly seen in forensic practice, such as haematoma, abnormal gas collections, fractures, and metallic foreign bodies. In the next 5-10 years most forensic institutes will seek regular access to such CT facilities or install machines into their own mortuaries. MRI is technically more problematic in the deceased but the improved tissue contrast over CT means that it is also very useful for investigation of pathology in the cranial, thoracic, and abdominal cavities, as well as the detection of haematoma in soft tissue. In order for radiologists to be an integral part of this important development in forensic investigation, radiological organizations must recognize the subspecialty of post-mortem radiology and provide a forum for radiologists to advance scientific knowledge in the field.