Post-mortem computed tomography angiography: past, present and future

The role of imaging has been long established in forensic practice as an adjunct to the conventional autopsy. Recently with the development of MDCT, there has been a large international push towards the development of the so called “near virtual autopsy.” Currently a large obstacle to the acceptance of “near virtual autopsies” is the failure of post-mortem imaging to yield detailed information about the coronary arteries. This is a major deficiency of post-mortem MDCT and MRI compared to conventional autopsy as standard clinical angiography relies on circulation. One possible way to overcome this is by the use of post-mortem MDCT angiography. This review paper considers the past, current and future advances in cadaver cardiac imaging which, if successful, will take radiological imaging one step closer to the widespread introduction of near virtual autopsies.     

Forensic relevance of post-mortem CT imaging of the haemopericardium in determining the cause of death

The post-mortem diagnosis of pericardial tamponade is associated with several medical legal problems. Thus, we explored whether post-mortem computed tomography might provide useful and reliable information for the diagnosis of this relevant disease in combination with autopsy data.We retrospectively reviewed the post-mortem computed tomography and autopsy reports of 15 autopsy cases with haemopericardium detected at the Institute of Forensic Medicine in Berne from July 2005 to February 2010.Two computer tomography findings were examined in combination with autopsy results. The first was the “hyperdense armoured heart,” which has been previously described as post-mortem evidence of heart beating for a time after the initiation of intrapericardial bleeding. The second was the “flattening of the anterior surface” of the heart which has been previously observed in vivo as a sign of the compression effect of the haemopericardium on the heart.Our retrospective analysis showed the combined presence of both of these findings in all cases of autopsy evidence of pericardial tamponade with the exception of one case. In contrast, the concomitance of both of them was never observed in cases of autopsy death due to haemorrhage in which neither the flattening of the anterior surface of the heart was detected except for one case.In conclusion, these results should be considered a first step toward the potentially using post-mortem computed tomography in combination with autopsy data in the diagnosis of pericardial tamponade especially considering the possibility to detect sign as the flattened heart signal which cannot be assessed after opening the pericardium at autopsy.     

Diagnosis of fatal pulmonary fat embolism with minimally invasive virtual autopsy and post-mortem biopsy

We report a case of a 78-year-old female with a proximal femur fracture caused by an accidental fall who died suddenly 1 h after orthopaedic prosthesis insertion. Post-mortem computed tomography (CT) scan and histological examination of samples obtained with post-mortem percutaneous needle biopsies of both lungs were performed. Analysis of the medical history and the clinical scenario immediately before death, imaging data, and biopsy histology established the cause of death without proceeding to traditional autopsy. It was determined to be acute right ventricular failure caused by massive pulmonary fat embolism. Although further research in post-mortem imaging and post-mortem tissue sampling by needle biopsies is necessary, we conclude that the use of CT techniques and percutaneous biopsy, as additional tools, can offer a viable alternative to traditional autopsy in selected cases and may increase the number of minimally invasive forensic examinations performed in the future.     

Advances of dual source,dual-energy imaging in postmortem CT

This paper focuses on the use of multi-detector row dual-energy computed tomography (DECT) in the evaluation of postmortal examinations. The use of dual energy moves postmortem CT to an entirely new dimension of diagnostic sensitivity where contrast in the image is not merely limited to X-ray attenuation differences, but may include elements of functional and tissue characterization. This additional information may be used to improve the benefit postmortem imaging can provide to supplement and simplify the conventional autopsy.     

Advances of dual source, dual-energy imaging in postmortem CT

This paper focuses on the use of multi-detector row dual-energy computed tomography (DECT) in the evaluation of postmortal examinations. The use of dual energy moves postmortem CT to an entirely new dimension of diagnostic sensitivity where contrast in the image is not merely limited to X-ray attenuation differences, but may include elements of functional and tissue characterization. This additional information may be used to improve the benefit postmortem imaging can provide to supplement and simplify the conventional autopsy.     

Cardiac aneurysms and diverticula: magnetic resonance and computed tomography appearances

Echocardiography is the first-line imaging modality for assessment of structural heart disease but magnetic resonance imaging and multi-detector computed tomography are being increasingly used for cardiac morphologic assessment. Aneurysms and diverticulae of the cardiac chambers and related structures represent a diverse group of conditions with varying etiologies and clinical manifestations. This article reviews the magnetic resonance imaging and multi-detector computed tomography features of these lesions with consideration of the emerging role that cross-sectional imaging has to play in their evaluation. Radiologists should be familiar with the salient imaging appearances of these conditions to facilitate optimal patient management.     

Differentiation of antemortem pulmonary thromboembolism and postmortem clot with unenhanced MRI: a case report

We report a case of a 39-year-old woman who died of fulminant pulmonary thromboembolism (PE). Autopsy showed classical findings of fulminant PE with occlusion of the bilateral main stem pulmonary arteries. Ancillary testing revealed inherited thrombophilia (Prothrombin 20,210 G?>?A and MTHFR 677 C?>?T mutation). Pre-autopsy postmortem computed tomography was used to test whether virtual imaging studies alone (virtual autopsy) would be sufficient to detect PE. Our studies show that computed tomography (CT) can differentiate antemortem clots from a postmortem clot in certain cases, particularly when combined with magnetic resonance imaging (MRI), which is superior in the assessment of soft tissue. We show that postmortem CT and MRI can aid in the diagnosis of pulmonary embolism by virtual autopsy, especially when used in conjunction.     

Demonstrating the origin of cardiac air embolism using post-mortem computed tomography; an illustrated case

An 83 year old female was found dead in her home. The deceased had been struck repeatedly to the head with at least one weapon, one of which was a hammer. The deceased had suffered both penetrating and non-penetrating blunt trauma to the head as a result of the assault. A multi-detector computed tomography (MDCT) scan was undertaken approximately 12h after death prior to the autopsy examination. This demonstrated the presence of a cardiac air embolus and continuity between the air embolus and the penetrating head injury. Air within the heart is a recognised post-mortem artefact frequently seen on MDCT scans and a common pitfall for inexperienced cadaveric MDCT reporters. This case builds upon a previous report by Kauczor, illustrating how MDCT can be used to demonstrate the origin and route of ingress of a genuine air embolism to the heart.     

Congenital anomalies of the aorta and vena cava: 16-detector-row CT imaging findings

Cardiovascular specialists should be aware of the common types of congenital vascular anomalies and understand their implications for the patient's treatment and the likelihood of associated morbidity. Conventional angiography, the gold standard in vascular imaging, is an invasive and expensive method. Therefore, in recent years, less invasive techniques such as computed tomography angiography (CTA) and magnetic resonance angiography have become more widely used. Because of the recent advances in CT technology, multi-detector CTA has replaced conventional angiography in most clinical applications. Multi-detector CTA is a relatively new method and is very useful in the diagnosis and management of congenital aorta and vena cava anomalies. This study presents the radiological images of congenital anomalies of the aorta and vena cava, obtained through multi-detector CTA.     

Minimally invasive post-mortem CT-angiography in a case involving a gunshot wound

Non-contrast post-mortem computed tomography (pm-CT) is useful in the evaluation of bony pathologies, whereas minimally invasive pm-CT-angiography allows for the detection of subtle vascular lesions. We present a case of an accidentally self-inflicted fatal bullet wound to the chest where pm-CT-angiography revealed a small laceration of the anterior interventricular branch of the left coronary artery and a tiny disruption of the right ventricle with pericardial and pleural effusion. Subsequent autopsy confirmed our radiological findings. Post-mortem CT-angiography has a great potential for the detection of vascular lesions and can be considered equivalent to autopsy for selected cases in forensic medicine.     

Post-mortem computed tomography and 3D imaging: anthropological applications for juvenile remains

Anthropological examination of defleshed bones is routinely used in medico-legal investigations to establish an individual's biological profile. However, when dealing with the recently deceased, the removal of soft tissue from bone can be an extremely time consuming procedure that requires the presence of a trained anthropologist. In addition, due to its invasive nature, in some disaster victim identification scenarios the maceration of bones is discouraged by religious practices and beliefs, or even prohibited by national laws and regulations. Currently, three different radiological techniques may be used in the investigative process; plain X-ray, dental X-ray and fluoroscopy. However, recent advances in multi-detector computed tomography (MDCT) mean that it is now possible to acquire morphological skeletal information from high resolution images, reducing the necessity for invasive procedures. This review paper considers the possible applications of a virtual anthropological examination by reviewing the main juvenile age determination methods used by anthropologists at present and their possible adaption to MDCT.     

CT based volume measurement and estimation in cases of pericardial effusion

The measurement of fluid volumes in cases of pericardial effusion is a necessary procedure during autopsy. With the increased use of virtual autopsy methods in forensics, the need for a quick volume measurement method on computed tomography (CT) data arises, especially since methods such as CT angiography can potentially alter the fluid content in the pericardium. We retrospectively selected 15 cases with hemopericardium, which underwent post-mortem imaging and autopsy. Based on CT data, the pericardial blood volume was estimated using segmentation techniques and downsampling of CT datasets. Additionally, a variety of measures (distances, areas and 3D approximations of the effusion) were examined to find a quick and easy way of estimating the effusion volume. Segmentation of CT images as shown in the present study is a feasible method to measure the pericardial fluid amount accurately. Downsampling of a dataset significantly increases the speed of segmentation without losing too much accuracy. Some of the other methods examined might be used to quickly estimate the severity of the effusion volumes.     

Injuries due to sharp trauma detected by post-mortem multislice computed tomography (MSCT): a feasibility study

Modern cross-sectional imaging techniques are being increasingly implemented in forensic pathology. In order to assess the practicability of such a method, namely post-mortem multislice computed tomography (MSCT) in cases of fatal cut and stab injuries, 12 corpses underwent such an examination prior to forensic autopsy. The questions regarding detection of foreign bodies, wound channels, skeletal and organ injuries, as well as the cause of death were addressed at MSCT and autopsy. The results of the two techniques revealed that post-mortem MSCT a useful tool in the assessment of such injuries.     

Investigation of the role of computed tomography as an adjunct to autopsy in the evaluation of stillbirth

Introduction

The number of parents agreeing to autopsy following stillbirth is declining, which has undermined clinicians’ ability to assess causes of intrauterine death and can impact counselling regarding recurrence. Post-mortem radiological imaging is a potential alternative method of investigating perinatal loss. The aim of this study was to assess the role of multi-detector computed tomography (MDCT) in the investigation of stillbirth.

Study design

Following ethical approval and written consent, parents were offered MDCT of the stillborn infant. MDCT was performed with 3D reconstruction, and images were analysed for image quality, anthropomorphic measurements and pathologic findings. Body part and organ-specific measurements were performed; including head, chest and abdominal circumferences, and muscle and liver mass was also measured. Findings were correlated with obstetric history, post-mortem skeletal survey (plain radiography), and formal autopsy.

Results

Fourteen third-trimester stillborn infants were scanned. Image quality was moderate to excellent for most body structures. CT was better than plain radiography for imaging skeletal structures and large solid organs and demonstrated a range of pathologies including renal vein thrombosis, mesenteric calcification and skeletal hyperostosis that were not seen on plain radiographs. MDCT did not overlook autopsy findings and provided some additional information.

Conclusion

This study confirms the feasibility of MDCT in the investigation of third trimester stillbirth. MDCT image quality is acceptable and the examination can demonstrate a range of anatomic and pathologic findings. Initially, its value may be as an important adjunct to conventional autopsy.     

Lethal hemorrhage from a ureteric–arterial–enteric fistula diagnosed by postmortem CT angiography

Fistula formation following pelvic surgery and radiotherapy, including ureteric?Carterial fistulas (UAF), is well documented, however, ureteric?Carterial?Centeric fistula is extremely rare. Conventional autopsy is usually required for the definitive diagnosis of pelvic vascular fistulas although an accurate diagnosis can still be complicated and challenging. The role of post-mortem computed tomography (PMCT) as an adjunct to conventional autopsy is well documented in the literature. One of the limitations of PMCT is the diagnosis of vascular conditions. Post-mortem computed tomography angiography (PMCTA) is a recently introduced technique that can assist in detecting such pathology. We present a case of post-radiotherapy ureteric?Carterial?Centeric fistula presenting as massive rectal and vaginal bleeding diagnosed prior to autopsy on PMCTA. The role of PMCTA in the diagnosis of such a UAF has not previously been reported in the literature.     

Cardiac positron emission tomography imaging

Cardiac positron emission tomography (PET) imaging has advanced from primarily a research tool to a practical, high-performance clinical imaging modality. The widespread availability of state-of-the-art PET gamma cameras, the commercial availability of perfusion and viability PET imaging tracers, reimbursement for PET perfusion and viability procedures by government and private health insurance plans, and the availability of computer software for image display of perfusion, wall motion, and viability images have all been a key to cardiac PET imaging becoming a routine clinical tool. Although myocardial perfusion PET imaging is an option for all patients requiring stress perfusion imaging, there are identifiable patient groups difficult to image with conventional single-photon emission computed tomography imaging that are particularly likely to benefit from PET imaging, such as obese patients, women, patients with previous nondiagnostic tests, and patients with poor left ventricular function attributable to coronary artery disease considered for revascularization. Myocardial PET perfusion imaging with rubidium-82 is noteworthy for high efficiency, rapid throughput, and in a high-volume setting, low operational costs. PET metabolic viability imaging continues to be a noninvasive standard for diagnosis of viability imaging. Cardiac PET imaging has been shown to be cost-effective. The potential of routine quantification of resting and stress blood flow and coronary flow reserve in response to pharmacologic and cold-pressor stress offers tantalizing possibilities of enhancing the power of PET myocardial perfusion imaging. This can be achieved by providing assurance of stress quality control, in enhancing diagnosis and risk stratification in patients with coronary artery disease, and expanding diagnostic imaging into the realm of detection of early coronary artery disease and endothelial dysfunction subject to risk factor modification. Combined PET and x-ray computed tomography imaging (PET-CT) results in enhanced patient throughput and efficiency. The combination of multislice computed tomography scanners with PET opens possibilities of adding coronary calcium scoring and noninvasive coronary angiography to myocardial perfusion imaging and quantification. Evaluation of the clinical role of these creative new possibilities warrants investigation.     

An unusual case of coronary artery fistula to the pulmonary artery,diagnosed with 64-MDCT coronary angiography

This report describes a case of complex coronary–pulmonary artery fistula with one feeding vessel from the proximal part of the right coronary. The complex anatomy of the fistula was shown in detail by multidetector computed tomography using multiplanar reconstruction and 3D volume rendering techniques.Traditionally, conventional angiography has been used for the diagnosis of coronary anomalies. With more frequent use of 64-row multi-detector computed tomography (CT) in chest and cardiac imaging, the number of incidentally found coronary artery fistulas has been increasing.     

The importance of post-mortem computed tomography (PMCT) in confrontation with conventional forensic autopsy of victims of motorcycle accidents

Since traffic accidents are an important problem in forensic medicine, there is a constant search for new solutions to help with an investigation process in such cases. In recent years there was a rapid development of post-mortem imaging techniques, especially post-mortem computed tomography (PMCT). In our work we concentrated on a potential advantage of PMCT in cases of motorcycle accident fatalities. The results of forensic autopsy were compared with combined results of the autopsy and PMCT to check in which areas use of these two techniques gives statistically important increase in number of findings. The hypothesis was confirmed in case of pneumothorax and fractures of skull, spine, clavicle, scapula, lower leg bones. As for majority of other bone fractures locations and brain injures there were single cases with pathologies visible only in PMCT, but too few to reach expected level of p-value. In case of injuries of solid organs and soft tissues statistical analysis did not confirmed any advantage of unenhanced PMCT use. On the whole it has been shown that PMCT used as an adjunct to forensic autopsy can cause an increase in information about vitally important regions in case of motorcycle accident fatalities.     

Pros and cons of post-mortem CT imaging on aspiration diagnosis

Recently, the field of forensics has experienced a rapid increase in the use of modern cross-sectional imaging in forensic investigations. We examined the value of post-mortem computed tomography (CT) imaging relative to autopsy for distinguishing aspiration into the lungs from airways, from lung alterations due to other causes, and for identifying the aspirated material. We selected 54 bodies submitted to whole-body CT scanning prior to autopsy. All cases had autopsy findings of blood (31 cases), fresh water (12 cases), or gastric content (11 cases) aspiration. The radiological images were retrospectively analyzed for airway and lung aspiration. In all cases, CT imaging detected pulmonary abnormalities suggestive of aspiration. Nevertheless, analysis of the CT images alone was not able to identify the aspirated material or to distinguish pulmonary findings of aspiration from lung changes due to other causes, except for a few cases of hemo-aspiration. However, due to its ability to visualize the entire parenchyma, CT imaging was superior to autopsy in providing additional data about the distribution and severity of the aspiration as well as in detecting small abnormalities. Post-mortem CT imaging should be considered as a superior tool for forensic investigations of aspiration due to its ability to document diagnostic conclusions and to guide the forensic pathologist during lung tissue examination.