Sudden death after chest pain: feasibility of virtual autopsy with postmortem CT angiography and biopsy

Contrast-enhanced postmortem computed tomography in clinical pathology: enhanced value of 20 clinical autopsies

Postmortem computed tomography (PMCT) is a modern tool that complements autopsy diagnostics. In clinical autopsies, a major cause of death is cardiovascular disease. To improve the performance of PMCT in cardiovascular disease, full body angiography was developed (PMCT angiography [PMCTA]). Twenty PMCTA scans generated before autopsy were compared with native PMCT and clinical autopsy. The objective of the study was to quantify the additional diagnostic value of adding angiography to native imaging and to compare PMCT and PMCTA findings to autopsy findings. The diagnosis of the cause of death was identical or overlapped in 80% of the cases that used PMCTA and 70% that used PMCT. The additional diagnostic yield given by PMCT and PMCTA in combination with autopsy was 55%. PMCT yielded additional diagnoses in the musculoskeletal system. The greatest additional diagnostic value of PMCTA was in association with cardiovascular diagnoses. The accuracy of PMCTA for cardiac causes of death was 80%, and the positive predictive value was 90%. The findings indicate that native PMCT cannot display the cardiovascular system sufficiently clearly for high-quality diagnostic assessment. However, PMCTA is a powerful tool in autopsy cases with a history of cardiovascular disease and/or a suspected cardiovascular cause of death. The combination of PMCTA and clinical autopsy enhances diagnostic quality and completeness of the autopsy report. Furthermore, in cases without consent or with a restricted consent for clinical autopsy, PMCTA has the potential to provide information on cardiovascular causes of death.

Times have changed! Forensic radiology--a new challenge for radiology and forensic pathology

OBJECTIVE

The ongoing development of imaging and the recent integration of cross-sectional imaging methods into the medicolegal workflow have resulted in an increasing number of forensic institutes acquiring dedicated CT and MRI scanners. The purpose of this article is to evaluate the different aspects of postmortem imaging and to detail the necessary cooperation between radiologists and forensic pathologists for mutual learning and accurate science to form a new subspecialty: forensic radiology. CONCLUSION; Forensic radiology must integrate the expertise of forensic pathologists and radiologists. The challenge is to unite these two disciplines first by direct and intense communications and second by a basic understanding of forensic pathology by radiologists as well as a foundational knowledge of postmortem imaging by forensic pathologists, in combination with the establishment of educational and reporting guidelines.

Optimization of inversion time for postmortem short-tau inversion recovery (STIR) MR imaging

PURPOSE

Signal intensity and image contrast differ between postmortem magnetic resonance (PMMR) images and images acquired from the living body. We sought to achieve sufficient fat suppression with short-tau inversion recovery (STIR) PMMR imaging by optimizing inversion time (TI).

MATERIAL AND METHODS

We subjected 37 deceased adult patients to PMMR imaging at 1.5 tesla 8 to 60 hours after confirmation of death and measured T1 values of areas of subcutaneous fat with relaxation time maps. Rectal temperature (RT) measured immediately after PMMR ranged from 6 to 31°C. We used Pearson's correlation coefficient to analyze the relationship between T1 and relaxation time (RT). We compared STIR images from 4 cadavers acquired with a TI commonly used in the living body and another TI calculated from the linear regression of T1 and RT.

RESULTS

T1 values of subcutaneous fat ranged from 89.4 to 182.2 ms. There was a strong, positive, and significant correlation between T1 and RT (r = 0.91, P < 0.0001). The regression expression for the relationship was T1 = 2.6*RT + 90 at a field strength of 1.5T. The subcutaneous fat signal was suppressed more effectively with the optimized TI.

CONCLUSION

The T1 value of subcutaneous fat in PMMR correlates linearly with body temperature. Using this correlation to determine TI, fat suppression with PMMR STIR imaging can be easily improved.

The use of contrast-enhanced post Mortem CT in the detection of cardiovascular deaths

OBJECTIVES

To evaluate the diagnostic value of contrast enhanced post mortem computed tomography (PMCT) in comparison to non-enhanced post mortem CT in the detection of cardiovascular causes of death (COD).

BACKGROUND

As autopsy rates decline, new methods to determine CODs are necessary. So contrast enhanced PMCT shall be evaluated in comparison to established non-enhanced PMCT in order to further improve the method.

METHODS

In a prospective study, 20 corpses were examined using a 64-row multisclice CT (MSCT) before and after intraarterial perfusion with a newly developed, barium-bearing contrast agent and ventilation of the lungs. The cause of death was determined in enhanced and unenhanced scans and a level of confidence (LOC) was given by three experienced radiologists on a scale between 0 and 4. Results were compared to autopsy results as gold standard. Autopsy was performed blinded to PMCT-findings.

RESULTS

The method allowed visualization of different types of cause of death. There was a significant improvement in LOC in enhanced scans compared to unenhanced scans as well as an improvement in the detection of COD. The cause of death could be determined in 19 out of 20 patients.

CONCLUSIONS

PMCT is feasible and appears to be robust for diagnosing cardiovascular causes of death. When compared with unenhanced post-mortem CT intraarterial perfusion and pulmonary ventilation significantly improve visualization and diagnostic accuracy. These promising results warrant further studies.

Postmortem CT compared to autopsy in children; concordance in a forensic setting

OBJECTIVES

The aim of this study is to assess the accuracy of postmortem CT (PMCT) in determining the cause of death in children who underwent a forensic autopsy because of a suspected nonnatural death.

METHODS

We selected forensic pediatric autopsies at the Netherlands Forensic Institute, whereby the subject underwent PMCT between 1-1-2008 and 31-12-2012. Cause of death was independently scored by a radiologist and a pathologist. Cause of death was classified (1) in categories being natural, unnatural, and unknown; (2) according to the ICD-10; and (3) according to institutional classification.

RESULTS

In the study period, 189 pediatric forensic autopsies were performed. Fifteen were excluded because of putrefaction. Of the remaining 174 autopsies, 98 (56%) underwent PMCT. PMCT and autopsy identified the same category in 69/98 cases (70%, kappa 0.49). They identified the same cause of death in 66/98 cases (67%, kappa 0.5) using ICD-10; in 71/98 (72%, kappa 0.62) using a forensic classification. PMCT performed better in unnatural deaths (59-67 % agreement) than in natural deaths (0 % agreement). If no cause of death was detected with autopsy, PMCT failed to identify a cause of death in 98% (39/40).

CONCLUSIONS

Pediatric PMCT does identify the majority of unnatural causes of death, but does not identify new diagnoses (true positives) if no cause of death is found during autopsy. Diagnostic accuracy in natural deaths is low.

KEY POINTS

• The case mix is an important predictor for the concordance between PMCT and autopsy. • In case of an unnatural death, 72--81% of PMCT results matches autopsy results. • In case of a natural death, 0% of PMCT results matches autopsy results. • If no cause of death is identified with autopsy, 98% of PMCT results concurs.

Feasibility of resuscitation contrast-enhanced postmortem computed tomography using cardiopulmonary resuscitation technique with chest compression immediately after death

Purpose

Our purpose was to evaluate image delineation ability of contrast-enhanced post-mortem computed tomography (CEPMCT) using cardiopulmonary resuscitation technique of chest compression, named “resuscitation CEPMCT”.

Materials and methods

Non-traumatically-deceased 15 subjects (7 men; 8 women) aged 19–87 years (mean 61 years) underwent resuscitation CEPMCT. The contrast-enhanced technique, while injecting 100 ml of contrast media from the right cubital vein at a rate of 1 ml/s, chest compression was performed for 2 minutes at a rate of 100 times/min (a total of 200 times). CT attenuation values (Hounsfield Unit: HU) were measured in 8 target vessels: 1) pulmonary artery, 2) coronary artery, 3) ascending aorta, 4) abdominal aorta, 5) celiac trunk, 6) common iliac artery, 7) superior vena cava, and 8) inferior vena cava. One-sided Student’s t-test was performed to assess whether measured values were higher than 140 HU by setting p-value at 0.05.

Results

Measured CT values in the 8 vessels were 1) pulmonary artery: 325 ± 140 HU, 2) coronary artery: 240 ± 73 HU, 3) ascending aorta: 321 ± 127 HU, 4) abdominal aorta: 286 ± 96 HU, 5) celiac trunk: 233 ± 62 HU, 6) common iliac artery: 260 ± 114 HU, 7) superior vena cava: 422 ± 187 HU, and 8) inferior vena cava: 301 ± 142 HU, showing significantly higher values than the threshold value of 140 HU. Resuscitation CEPMCT detected one case of pulmonary arterial thromboemboli death.

Conclusion

Resuscitation CEPMCT using chest compression immediately after death has the possibility of detecting thromboembolus in major vessels, despite the simplicity of the technique.

Electronic supplementary material

The online version of this article (doi:10.1186/2193-1801-2-663) contains supplementary material, which is available to authorized users.

Minimally invasive autopsy employing post-mortem CT and targeted coronary angiography: evaluation of its application to a routine Coronial service

AIMS

Post-mortem imaging is a potential alternative to traditional medicolegal autopsy. We investigate the reduction in number of invasive autopsies required by use of post-mortem CT ± coronary angiography.

METHODS AND RESULTS

A total of 120 adult deaths referred to the Coroner were investigated by CT, with coronary angiography employed only for the second series of 60 cases, in order to determine the added value of angiography. The confidence of imaging cause of death was classified as definite (no autopsy), probable, possible or unascertained. Invasive autopsy was not required in 38% of cases without coronary angiography and 70% of cases with angiography. Full autopsy, including brain dissection, was required in only 9% of cases. There was complete agreement between autopsy and radiological causes of death in the cases with a 'probable' imaging cause of death, indicating that cases for which imaging provides an accurate cause of death without autopsy were identified correctly. In two patients, CT demonstrated unsuspected fractures, not detected at subsequent autopsy.

CONCLUSIONS

A two-thirds reduction in the number of invasive coronial autopsies can be achieved by use of post-mortem CT plus coronary angiography. At the same time, use of post-mortem CT may improve accuracy of diagnosis, particularly for traumatic deaths.

Post-mortem MRI versus conventional autopsy in fetuses and children: a prospective validation study

BACKGROUND

Post-mortem MRI is a potential diagnostic alternative to conventional autopsy, but few large prospective studies have compared its accuracy with that of conventional autopsy. We assessed the accuracy of whole-body, post-mortem MRI for detection of major pathological lesions associated with death in a prospective cohort of fetuses and children.

METHODS

In this prospective validation study, we did pre-autopsy, post-mortem, whole-body MRI at 1·5 T in an unselected population of fetuses (≤24 weeks' or >24 weeks' gestation) and children (aged <16 years) at two UK centres in London between March 1, 2007 and Sept 30, 2011. With conventional autopsy as the diagnostic gold standard, we assessed MRI findings alone, or in conjunction with other minimally invasive post-mortem investigations (minimally invasive autopsy), for accuracy in detection of cause of death or major pathological abnormalities. A radiologist and pathologist who were masked to the autopsy findings indicated whether the minimally invasive autopsy would have been adequate. The primary outcome was concordance rate between minimally invasive and conventional autopsy.

FINDINGS

We analysed 400 cases, of which 277 (69%) were fetuses and 123 (31%) were children. Cause of death or major pathological lesion detected by minimally invasive autopsy was concordant with conventional autopsy in 357 (89·3%, 95% CI 85·8-91·9) cases: 175 (94·6%, 90·3-97·0) of 185 fetuses at 24 weeks' gestation or less, 88 (95·7%, 89·3-98·3) of 92 fetuses at more than 24 weeks' gestation, 34 (81·0%, 66·7-90·0) [corrected] of 42 newborns aged 1 month or younger, 45 (84·9%, 72·9-92·1) of 53 infants aged older than 1 month to 1 year or younger, and 15 (53·6%, 35·8-70·5) of 28 children aged older than 1 year to 16 years or younger. The dedicated radiologist or pathologist review of the minimally invasive autopsy showed that in 165 (41%) cases a full autopsy might not have been needed; in these cases, concordance between autopsy and minimally invasive autopsy was 99·4% (96·6-99·9).

INTERPRETATION

Minimally invasive autopsy has accuracy similar to that of conventional autopsy for detection of cause of death or major pathological abnormality after death in fetuses, newborns, and infants, but was less accurate in older children. If undertaken jointly by pathologists and radiologists, minimally invasive autopsy could be an acceptable alternative to conventional autopsy in selected cases.

FUNDING

Policy research Programme, Department of Health, UK.

The utility of postmortem computed tomography selective coronary angiography in parallel with autopsy

Historically, coronary angiography of the isolated heart has played an important role in the detection of stenotic or occlusive lesions that are difficult to identify by autopsy alone. Meanwhile, although the application of multidetector computed tomography (MDCT) to forensic fields has accelerated recently, isolated single organ angiography with MDCT is rarely performed. In this article, we present an evaluation of postmortem selective coronary CT angiography of the isolated heart with MDCT and discuss its utility for autopsy. First, in a preliminary experiment using pig coronary artery, we examined the behavior of water soluble contrast material on postmortem computed tomography angiography (PMCTA) and found that better angiographic images were acquired when the viscosity of the contrast material was increased and CT was performed under conditions of sustained perfusion. Based on these results, we devised a selective coronary angiography procedure using a pressurized bag for drip infusion that can be performed easily, quickly, and at low cost. The angiographic images obtained provided useful supportive evidence of autopsy findings suggestive of ischemic heart disease. With active discussions underway in forensic fields on the proper use of postmortem computed tomography, PMCTA has also naturally attracted attention as it compensates for some of the shortcomings of CT alone. Although PMCTA typically involves whole-body angiography, if we view PMCTA as one of the many useful and supplementary tools available for autopsy, then isolated heart angiography continues to have utility in autopsy today.

The effect on cadaver blood DNA identification by the use of targeted and whole body post-mortem computed tomography angiography

Post-mortem computed tomography angiography (PMCTA) involves the injection of contrast agents. This could have both a dilution effect on biological fluid samples and could affect subsequent post-contrast analytical laboratory processes. We undertook a small sample study of 10 targeted and 10 whole body PMCTA cases to consider whether or not these two methods of PMCTA could affect post-PMCTA cadaver blood based DNA identification. We used standard methodology to examine DNA from blood samples obtained before and after the PMCTA procedure. We illustrate that neither of these PMCTA methods had an effect on the alleles called following short tandem repeat based DNA profiling, and therefore the ability to undertake post-PMCTA blood based DNA identification.

Multidetector CT investigation of the mummy of Rosalia Lombardo (1918-1920)

Whole-body multidetector computed tomography (CT) was performed on the mummified corpse of two-year-old Rosalia Lombardo, an anthropogenic mummy displayed in the Capuchin Catacombs of Palermo, Sicily, Italy. Rosalia Lombardo reportedly died of bronchopneumonia in 1920 and was preserved by the embalmer and taxidermist Alfredo Salafia with a formaldehyde-based fluid. Rosalia Lombardo's body is still exhibited in the Capuchin Catacombs inside the original glass-topped coffin in which she was placed. Only her head is visible: the rest of her body is covered by a sheet. CT images of Rosalia's body within her coffin were of reduced quality because of distinct metal artifacts caused by the coffin itself. Nevertheless, a detailed radiological analysis was possible for most of the body. Analysis of the data from the CT examination revealed indicators for the historically-reported endovasal and intracavity treatment. Rosalia's entire body was preserved in a remarkable state. The exceptional preservation of her internal organs made it possible to consider a radiological diagnosis of pneumonia. For this study, CT was determined to be the ultimate method for investigation, since Rosalia's body had to be kept untouched in her sealed coffin for conservation purposes. The CT examination offered new insights into the current preservation status of the body, and the superior contrast of CT allowed detailed assessment of different tissues. Post-processing methods provided reconstructions on any desired plane, as well as three-dimensional reconstruction, for the best possible visualization and interpretation of the body.

To see or not to see -- ambiguous findings on post-mortem cross-sectional imaging in a case of ruptured abdominal aortic aneurysm

We present a case of a ruptured abdominal aortic aneurysm (AAA) with ambiguous accessory findings on post-mortem computed-tomography (PMCT), post-mortem magnetic resonance (PMMR) imaging, and PMCT-angiography (PMCTA) suggestive of thoracic aortic dissection. The diagnosis of ruptured AAA was confirmed by autopsy; however, there was no aortic dissection. The imaging findings that mimicked the presence of aortic dissection might have been an atypical presentation of post-mortem clotting or sedimentation. This case is an ideal example to illustrate benefits, limitations, and challenges of post-mortem cross-sectional imaging. It serves as a reminder that both, training as well as correlation of imaging findings with autopsy are fundamental to improve our understanding of radiologic findings on post-mortem cross-sectional imaging.

Acute aortic syndromes

Acute aortic syndrome is a term that describes one of a number of different pathologic entities. Each of these conditions requires urgent or emergent evaluation and may possibly require surgical intervention. However, both entities may be unfamiliar to the nonsurgical (and in some cases, surgical) practitioner and they may mimic more common diseases or be missed entirely. An understanding of the processes, nomenclature, and management options is critical in optimizing patient care.

Postmortem imaging of sudden cardiac death

Postmortem imaging is increasingly used in forensic practice in cases of natural deaths related to cardiovascular diseases, which represent the most common causes of death in developed countries. While radiological examination is generally considered to be a good complement for conventional autopsy, it was thought to have limited application in cardiovascular pathology. At present, multidetector computed tomography (MDCT), CT angiography, and cardiac magnetic resonance imaging (MRI) are used in postmortem radiological investigation of cardiovascular pathologies. This review presents the actual state of postmortem imaging for cardiovascular pathologies in cases of sudden cardiac death (SCD), taking into consideration both the advantages and limitations. The radiological evaluation of ischemic heart disease (IHD), the most frequent cause of SCD in the general population of industrialized countries, includes the examination of the coronary arteries and myocardium. Postmortem CT angiography (PMCTA) is very useful for the detection of stenoses and occlusions of coronary arteries but less so for the identification of ischemic myocardium. MRI is the method of choice for the radiological investigation of the myocardium in clinical practice, but its accessibility and application are still limited in postmortem practice. There are very few reports implicating postmortem radiology in the investigation of other causes of SCD, such as cardiomyopathies, coronary artery abnormalities, and valvular pathologies. Cardiomyopathies representing the most frequent cause of SCD in young athletes cannot be diagnosed by echocardiography, the most widely available technique in clinical practice for the functional evaluation of the heart and the detection of cardiomyopathies. PMCTA and MRI have the potential to detect advanced stages of diseases when morphological substrate is present, but these methods have yet to be sufficiently validated for postmortem cases. Genetically determined channelopathies cannot be detected radiologically. This review underlines the need to establish the role of postmortem radiology in the diagnosis of SCD.

Accuracy of targeted post-mortem computed tomography coronary angiography compared to assessment of serial histological sections

Post-mortem computed tomography with coronary angiography (PMCTA) could have a role in the investigation of sudden natural death. This study assesses the accuracy of targeted coronary PMCTA, using both air and iodinated contrast media, to provide sensitivity and specificity for critical stenosis (CS) on a segmental basis, based on a gold standard of 3-5 mm serial sections of the coronary arteries using macroscopic and histological techniques. Assessment of stenosis at 1 mm intervals on PMCTA was compared with the data from pathological analysis. Stenosis was defined as "critical" when the stenotic region reaches ≥75 %. Regions were defined every 20 mm or by a clear change in stenosis. Discrepancies were defined as significant if only one test showed CS. Five cases with 25 vessels with 124 regions were assessed. PMCTA was unable to identify plaque hemorrhage or dissection (but this was normally associated with CS). Eighteen segments had significant discrepancies, giving a sensitivity and specificity of 50 and 91.5 %. When an alternative gold standard was constructed by excluding regions beyond a CS (five cases), taking PMCTA as correct where a heavily calcified vessel opens under contrast injection (four cases), and correcting for misregistration of distance (one case), the sensitivity rose to 85.7 %. There was complete agreement when the right or left coronary arteries are assessed as a whole. This study shows that PMCTA is not a perfect replacement for histological examination of coronary vessels, but may have a role in routine post-mortem investigation.