Reduction of postmortem angiography-induced tissue edema by using polyethylene glycol as a contrast agent dissolver

A calcification subtraction method for postmortem coronary computed tomography angiography

Although coronary computed tomography (CT) angiography is a useful tool for evaluating coronary artery lesions both ante- and postmortem, accurate evaluation of the lumen is difficult when highly calcified lesions are present, owing to overestimation of stenosis caused by blooming and partial volume artifacts. In clinical practice, to overcome this diagnostic problem, a subtraction method has been devised to remove calcification by subtracting the precontrast image from the contrast image. In this report, we describe a calcification subtraction method using image analysis software for postmortem coronary CT angiography. This method was devised based on preliminary experimental results showing that the most accurate subtraction was achieved using images reconstructed with a narrower field of view and bone kernel, resulting in higher spatial resolution. This subtraction method allowed evaluation of lumen patency and the degree of stenosis on contrast-enhanced images in a verification using actual specimens where evaluation of the lumen had been difficult because of high calcification. The results were morphologically similar to the macroscopic findings. This method allows more rapid and reliable lesion retrieval and is expected to be useful for postmortem coronary angiography in forensic practice.

Pediatric forensic postmortem computed tomography: basics to advanced

The approach to postmortem computed tomography (CT) differs significantly from that of diagnostic CT in living patients. Elimination of artifacts such as noise and beam hardening as well as optimization of tissue contrast requires alteration of exposure parameters from protocols designed to limit radiation dose in children. Multiple scans may be performed, and detailed post-processing can be used to enhance subtle findings such as small intracranial extra axial collections and non-displaced fractures. Basics of postmortem CT technique are discussed here as well as advanced techniques in scanning and post-processing.

Postmortem contrast-enhanced computed tomography via direct large-vessel puncture

The aim of this study was to assess the usefulness of postmortem contrast-enhanced CT (PMeCT) performed via direct large-vessel puncture when routine postmortem CT suggests a vascular lesion as the cause of death. PMeCT was performed in 9 cases (4 male, 5 female) with a mean age of 76 years (range 52-92) at the time of death. The mean time elapsed since death was 29.1 h (12.0-72.0). The location of the target vessel for puncture was determined based on the CT table position and a grid placed on the body surface. An 18-G spinal needle was advanced to the puncture site, and the needle tip was confirmed to have reached the intended blood vessel. Using negative pressure with a 20-ml syringe, the needle tip was advanced until reverse bleeding was confirmed. Diluted contrast medium was injected slowly to ensure its dispersion within the blood vessels. Following confirmation of no extravasation, additional doses of diluted contrast agent were injected in 3-4 divided doses, with CT scans obtained at each step to track the distribution of contrast agent over time. PMeCT was successful in all cases, revealing cardiac tamponade in 7 (ascending aortic dissection, n = 6; cardiac rupture, n = 1), thoracic aortic aneurysm rupture, n = 1, and iliac artery aneurysm rupture, n = 1. There were no cases of procedure-related extravasation (pseudo-lesions). When postmortem CT reveals pericardial hematoma or bleeding in the thoracic or abdominal cavity, PMeCT can identify the source of bleeding.

Development of a protocol for standardized use of a water-soluble contrast agent with polyethylene glycol in post-mortem CT angiography

Computed tomography angiography (PMCTA) is increasingly used in postmortem cases. Standardized validated protocols permit to compare different PMCTA images and make it more easily to defend a case in court. In addition to the well-known technique by Grabherr et al. (2011) which is using paraffin oil as a carrier substance, water-soluble polyethylene glycol 200 (PEG200) can be used in combination with the contrast agent Accupaque® 300. As to date, there exists no standardized protocol for the use of this contrast agent mixture, the aim of this study was to develop a protocol using it. Between 2012 and 2022, 23 PMCTA with PEG200 and Accupaque®300 were performed at the University Centre of Legal Medicine Lausanne (Switzerland) and the Institute of Forensic Medicine Munich (Germany). The images obtained were evaluated regarding the opacification of the vessels and possible artefacts. The best image quality was obtained with a mixing ratio of 1:15 (Accupaque®300:PEG200) and a perfusion volume of 1000 ml in the arterial, 1400 ml in the venous and 350 ml in the dynamic phase. The infusion rates described by Grabherr et al. were confirmed for the three phases. Overall, the opacification of the vessels was diagnostically sufficient. In 13 cases no opacification of the right coronary artery was observed due to a stratification artefact. By using the PMCTA protocol with PEG200 as a carrier, a good overall image quality can be achieved. This protocol offers the possibility to standardize PMCTA with PEG200.

Toward an optimal cadaveric brain model for neurosurgical education: assessment of preservation, parenchyma, vascular injection, and imaging

OBJECTIVE

We assessed types of cadaveric head and brain tissue specimen preparations that are used in a high throughput neurosurgical research laboratory to determine optimal preparation methods for neurosurgical anatomical research, education, and training.

METHODS

Cadaveric specimens (N = 112) prepared using different preservation and vascular injection methods were imaged, dissected, and graded by 11 neurosurgeons using a 21-point scale. We assessed the quality of tissue and preservation in both the anterior and posterior circulations. Tissue quality was evaluated using a 9-point magnetic resonance imaging (MRI) scale.

RESULTS

Formalin-fixed specimens yielded the highest scores for assessment (mean ± SD [17.0 ± 2.8]) vs. formalin-flushed (17.0 ± 3.6) and MRI (6.9 ± 2.0). Cadaver assessment and MRI scores were positively correlated (P < 0.001, R2 0.60). Analysis showed significant associations between cadaver assessment scores and specific variables: nonformalin fixation (β = -3.3), preservation within ≤72 h of death (β = 1.8), and MRI quality score (β = 0.7). Formalin-fixed specimens exhibited greater hardness than formalin-flushed and nonformalin-fixed specimens (P ≤ 0.006). Neurosurgeons preferred formalin-flushed specimens injected with colored latex.

CONCLUSION

For better-quality specimens for neurosurgical education and training, formalin preservation within ≤72 h of death was preferable, as was injection with colored latex. Formalin-flushed specimens more closely resembled live brain parenchyma. Assessment scores were lower for preparation techniques performed > 72 h postmortem and for nonformalin preservation solutions. The positive correlation between cadaver assessment scores and our novel MRI score indicates that donation organizations and institutional buyers should incorporate MRI as a screening tool for the selection of high-quality specimens.

The effect of post-mortem computed tomography angiography (PMCTA) on biomarkers of coronary artery disease

Coronary atherosclerosis is due to build-up of plaque within the coronary arteries. Post-mortem computed tomography (PMCT) allows non or minimally invasive visualization of abnormalities prior to an autopsy, however PMCT-angiography (PMCTA) greatly enhances relevant findings, especially in viewing the cardiovascular system which is important in the diagnosis of coronary atherosclerosis. Contrast media used in PMCTA however has been reported to cause distortion of tissue which may interfere with post-mortem investigation outcomes. A cross sectional study to investigate the effect of PMCTA on tissue biomarkers in coronary arteries was performed involving cases brought in dead to the Institute and Accident and Emergency Unit. Sixty-three autopsy cases were included in this study, whereby 18 cases underwent PMCT while 45 cases underwent PMCTA. The subjects subsequently had a conventional autopsy where coronary artery sections were collected for standard histological examination and immunohistochemistry examination for endothelial inflammatory (CD36), prothrombogenic (TPA) and plaque stability (MMP-9) markers. The subjects consisted of 55 males and 8 females with a mean age ±SD of 49 ± 18.11 years. There were no significant differences in the coronary artery endothelial expression of CD36, MMP-9 and TPA between PMCT and PMCTA subjects. PMCTA does not alter CD36, TPA and MMP-9 markers supporting the safe use of PMCTA in post-mortem examinations.

A Practical Guide to Virtual Autopsy: Why, When and How

Postmortem imaging is considered a routine investigative modality in many forensic institutions worldwide. Because of its ability to provide a quick and complete documentation of skeletal system and major parenchymal alterations, postmortem computed tomography (PMCT) is the imaging technique most frequently applied in postmortem forensic investigations. Also postmortem magnetic resonance has been implemented in postmortem setting, but its use is mostly limited to focused analysis (eg, study of the heart and brain). PMCT presents some limits in investigating "natural" deaths, particularly related to its poor ability in differentiating soft tissue interfaces and in depicting vascular lesions. For this reason, PMCT angiography has been introduced. A major limitation of these postmortem imaging techniques is the absence of body samples for histopathologic, toxicologic, or microbiological analysis. This limit has been overcome by the introduction of postmortem percutaneous biopsies. The aim of this review is to provide a practical guide for virtual autopsy, with the intent of facilitating standardization and augmenting its quality. In particular, the indications of virtual autopsy as well protocols in PMCT examinations and its ancillary techniques will be discussed. Finally, the workflow of a typical virtual autopsy and its main steps will be described.

Systematic review of surgical training on reperfused human cadavers

BACKGROUND

The role of reperfused human cadavers in surgical training has not been established.

METHODS

Reports describing reperfused human cadaver models in terms of simulated surgeries, the use of tools to assess technical competency and skills transfer to patients, cadaver status and reperfusion techniques were included.

RESULTS

Thirty-five reports were included. Most participants practised vascular (n = 27), flap (n = 6) and trauma (n = 4) procedures. Training progression was evaluated objectively in only two studies. In two publications, flap techniques were practised on cadavers and repeated successfully in patients. Eighteen studies employed whole bodies. Fresh and embalmed cadavers were both used in 17 publications. Most embalmed cadavers were formalin-fixed (n = 10), resulting in stiffness. Few trainings were offered on soft Thiel-embalmed cadavers (n = 5). Only arteries were reperfused in 20 studies, while in 13 publications, the arteries and veins were filled. Arteries and/or veins were mostly pressurized (n = 21) and arterial flow was generated in 14 studies.

CONCLUSIONS

Various reperfused human cadaver models exist, enabling practise of mainly vascular procedures. Preservation method determines the level of simulation fidelity. Thorough evaluation of these models as surgical training tools and transfer effectiveness is still lacking.

Postmortem CT Angiography Compared with Autopsy: A Forensic Multicenter Study

Purpose

To determine if postmortem computed tomography (CT) and postmortem CT angiography help to detect more lesions than autopsy in postmortem examinations, to evaluate the strengths and weaknesses of each method, and to define their indications.

Materials and Methods

Postmortem CT angiography was performed on 500 human corpses and followed by conventional autopsy. Nine centers were involved. All CT images were read by an experienced team including one forensic pathologist and one radiologist, blinded to the autopsy results. All findings were recorded for each method and categorized by anatomic structure (bone, organ parenchyma, soft tissue, and vascular) and relative importance in the forensic case (essential, useful, and unimportant).

Results

Among 18 654 findings, autopsies helped to identify 61.3% (11 433 of 18 654), postmortem CT helped to identify 76.0% (14 179 of 18 654), and postmortem CT angiography helped to identify 89.9% (16 780 of 18 654; P < .001). Postmortem CT angiography was superior to autopsy, especially at helping to identify essential skeletal lesions (96.1% [625 of 650] vs 65.4% [425 of 650], respectively; P < .001) and vascular lesions (93.5% [938 of 1003] vs 65.3% [655 of 1003], respectively; P < .001). Among the forensically essential findings, 23.4% (1029 of 4393) were not detected at autopsy, while only 9.7% (428 of 4393) were missed at postmortem CT angiography (P < .001). The best results were obtained when postmortem CT angiography was combined with autopsy.

Conclusion

Postmortem CT and postmortem CT angiography and autopsy each detect important lesions not detected by the other method. More lesions were identified by combining postmortem CT angiography and autopsy, which may increase the quality of postmortem diagnosis.

Online supplemental material is available for this article.

Towards multi-phase postmortem CT angiography in children: a study on a porcine model

PURPOSE

Multi-phase postmortem computed tomography angiography (MPMCTA) is a growing technique, which is standardized for adults. Application of this protocol for a children population is not so well defined. Our study aims to adapt the adult's protocol to children, using a porcine model.

MATERIAL AND METHODS

Three groups of 18 pigs were studied, with a weight distribution between 4 and 48 kg. Different pump devices were used. Pigs of group I were studied using the Virtangio® machine, whereas pigs of groups II and III were studied using used the Medrad® machine. Study of vascular opacification was possible using a semi-quantitative method based on 26 arterial and 26 venous segments that were distributed over the entire body from the cephalic extremity to the posterior pawns.

RESULTS

While thoracic, abdominal, and pelvic vascular opacification were complete for each individual pig in a group, group III showed better vascular opacification for the cephalic extremity. This was also true for anterior and posterior pawns vascular opacification. Spearman correlation tests showed a significant relationship between anthropometric characteristics of pigs, injection parameters, and percentage of opacified segments. A higher percentage of opacification was obtained for individuals of lower weights, with comparatively lower quantities of contrast agent injected.

CONCLUSION

Postmortem computed tomography angiography (PMCTA) was possible for all the individuals, particularly for small weights (4 kg) using the Medrad® machine. However, further studies are needed to better understand the procedure.

Evolution of post-mortem coronary imaging: from selective coronary arteriography to post-mortem CT-angiography and beyond

Since the 1970s, remarkable efforts have been made in the post-mortem coronary study, especially by angiography, as an added tool to diagnose heart-related deaths. In more recent times, post-mortem CT (PMCT) and post-mortem CT-angiography (PMCTA) have become an established practice in numerous forensic units, because of the undeniable advantages these diagnostic instruments can offer: data acquisition times are increasingly fast, costs have become lower and, once acquired, data can be re-utilized and re-evaluated at any given time. This review aims to chart the history of post-mortem cardiac imaging, highlighting its evolution both in terms of methodology and technology as well as the contribution that forensic radiology has been able to offer to forensic pathology, not as an alternative to autopsy but as a guide and aid when performing one. Finally, the latest advances in the study of cardiac deaths are explored, namely by cardiac post-mortem MRI (PMMR), able to visualize all the various stages of a myocardial infarction, post-mortem MRI-angiography (PMMRA), useful in investigating coronary artery pathology and post-mortem cardiac micro-CT, able to provide near-histological levels of myocardial, coronary and valvular detail.

The effect of post-mortem computed tomography angiography (PMCTA) using water-soluble, iodine-based radiographic contrast on histological analysis of the liver, kidneys and left ventricle of the heart

The purpose of this study was to investigate the impact of post-mortem computed-tomography angiography (PMCTA) on the histology of the liver, kidneys and heart. Multiple tissue cores were collected from the liver, left and right kidneys and left ventricle utilizing CT-guided biopsy. Subsequent whole body PMCTA was performed using a solution of polyethylene glycol and iodinated radiographic contrast, and an embalming pump. Corresponding biopsy cores were collected at autopsy, and blinded histology analysis assessing for PMCTA-induced histology artefact was performed. The blinded analysis of pre-PMCTA and post-PMCTA biopsy samples demonstrated that whole body PMCTA had no effect on the histological analyses of the liver (0%, CI = 0-13.7%), left ventricle of the heart (0%, CI = 0-36.9%) and right kidney (0%, CI = 13.2%), however likely caused increased Bowman's capsule spaces in the left kidney of one case (4%, CI = 0.01-20.4%). Other artefactual histological changes identified included eosinophilic material in the liver, whiter interstitium and dilated tubules in kidney samples, and autolysis-related changes, however these could not be categorically attributed to the PMCTA procedure. PMCTA causes zero or minimal effect to the histological examination of the liver, left kidney, right kidney and left ventricle, and as such performing PMCTA prior to autopsy is unlikely to impact autopsy histological results in these organs.

Temperature dependence of viscosity, relaxation times (T1, T2) and simulated contrast for potential perfusates in post-mortem MR angiography (PMMRA)

Developments in post-mortem imaging increasingly focus on addressing recognised diagnostic weaknesses, especially with regard to suspected natural deaths. Post-mortem MR angiography (PMMRA) may offer additional diagnostic information to help address such weaknesses, specifically in the context of sudden cardiac death. Complete filling of the coronary arteries and acceptable contrast with surrounding tissue are essential for a successful approach to PMMRA. In this work, the suitability of different liquids for inclusion in a targeted PMMRA protocol was evaluated. Factors influencing cooling of paraffinum liquidum + Angiofil® (6 %) in cadavers during routine multiphase post-mortem CT angiography were investigated. The temperature dependence of dynamic viscosity (8–20 °C), longitudinal (T₁) and transverse (T₂) relaxation (1–23 °C) of the proposed liquids was quadratically modelled. The relaxation behaviour of these liquids and MR scan parameters were further investigated by simulation of a radiofrequency (RF)-spoiled gradient echo (GRE) sequence to estimate potentially achievable contrast between liquids and post-mortem tissue at different temperatures across a forensically relevant temperature range. Analysis of the established models and simulations indicated that based on dynamic viscosity (27–33 mPa · s), short T₁ relaxation times (155–207 ms) and a minimal temperature dependence over the investigated range of these parameters, paraffin oil and a solution of paraffin oil + Angiofil® (6 %) would be most suitable for post-mortem reperfusion and examination in MRI.

Forensic 3D Visualization of CT Data Using Cinematic Volume Rendering: A Preliminary Study

OBJECTIVE

The 3D volume-rendering technique (VRT) is commonly used in forensic radiology. Its main function is to explain medical findings to state attorneys, judges, or police representatives. New visualization algorithms permit the generation of almost photorealistic volume renderings of CT datasets. The objective of this study is to present and compare a variety of radiologic findings to illustrate the differences between and the advantages and limitations of the current VRT and the physically based cinematic rendering technique (CRT).

MATERIALS AND METHODS

Seventy volunteers were shown VRT and CRT reconstructions of 10 different cases. They were asked to mark the findings on the images and rate them in terms of realism and understandability.

RESULTS

A total of 48 of the 70 questionnaires were returned and included in the analysis. On the basis of most of the findings presented, CRT appears to be equal or superior to VRT with respect to the realism and understandability of the visualized findings. Overall, in terms of realism, the difference between the techniques was statistically significant (p < 0.05). Most participants perceived the CRT findings to be more understandable than the VRT findings, but that difference was not statistically significant (p > 0.05).

CONCLUSION

CRT, which is similar to conventional VRT, is not primarily intended for diagnostic radiologic image analysis, and therefore it should be used primarily as a tool to deliver visual information in the form of radiologic image reports. Using CRT for forensic visualization might have advantages over using VRT if conveying a high degree of visual realism is of importance. Most of the shortcomings of CRT have to do with the software being an early prototype.

Post-mortem Reperfusion of a Pig: a First Step to a New Surgical Training Model?

The purpose of this experimental study was to establish a short-term post-mortem circulation in a pig model using liquid paraffin. This study also investigated the quality of vascular perfusion in the peripheral tissues. This is the first step in the development of a new revascularized human surgical training model. This first experience was performed on the hind leg of a pig. Initial cannulation of the external iliac artery and vein was followed by connection of the arterial inflow to a heart-lung machine and using the venous outflow to flush post-mortem clots and blood. Subsequently, after connecting the venous outflow to the heart-lung machine, circulation was initiated. Circulation was established during 27 min, during which the flow was constantly 130 mL/min. A steady increase in inlet pressure was observed during the experiment, which finally reached a minimum value of 124 mmHg. Perfusion was interrupted early due to an uncontrollable fluid leak. Afterwards, the distal hind leg was incised showing an equal distribution of paraffin. A short-term revascularization was successfully re-established under excellent conditions. Although the results are promising, further experiments are necessary to eventually perform a wide range of surgical procedures on revascularized human cadavers.

Postmortem-computed tomography and postmortem-computed tomography-angiography: a focused update

The use of multidetector CT (MDCT) represents a reality routinely used in several forensic institutes, for the numerous advantages that this diagnostic tool can provide; costs are becoming increasingly lower; data acquisition is always faster and once acquired may be revalued at any time. However, there are also some diagnostic limitations, for example, the visualization of the vascular system or a limited soft tissue contrast. In order to overcome these limitations, in recent years, contrast medium has been introduced in postmortem cases, with the development of several techniques of PMCT angiography (PMCTA) and standardized protocols to make them easily reproducible. The aim of this review is to highlight the advantages and pitfalls of PMCT and PMCTA in forensic investigation, taking into consideration the broad spectrum of applications both for natural and unnatural deaths and the numerous methods currently used. Secondly, in the light of the considerable progress in this field and the attempt to develop standardized protocols of PMCTA, the authors aim to evaluate the diagnostic value of PMCTA in comparison both to PMCT and conventional autopsy.

Sudden death due to coronary artery dissection associated with fibromuscular dysplasia revealed by postmortem selective computed tomography coronary angiography: A case report

We present an autopsy case of sudden death due to coronary artery dissection associated with fibromuscular dysplasia (FMD) in a young female patient. Postmortem selective coronary artery computed tomography (CT) angiography revealed dissections of the left anterior descending and left circumflex arteries. These findings were confirmed by subsequent autopsy. Histopathological examination revealed coronary artery FMD, which is considered a risk factor for dissection. To the best of our knowledge, this is the first postmortem radiology-pathology correlation of coronary artery dissection associated with FMD.

Application of contrast media in post-mortem imaging (CT and MRI)

The application of contrast media in post-mortem radiology differs from clinical approaches in living patients. Post-mortem changes in the vascular system and the absence of blood flow lead to specific problems that have to be considered for the performance of post-mortem angiography. In addition, interpreting the images is challenging due to technique-related and post-mortem artefacts that have to be known and that are specific for each applied technique. Although the idea of injecting contrast media is old, classic methods are not simply transferable to modern radiological techniques in forensic medicine, as they are mostly dedicated to single-organ studies or applicable only shortly after death. With the introduction of modern imaging techniques, such as post-mortem computed tomography (PMCT) and post-mortem magnetic resonance (PMMR), to forensic death investigations, intensive research started to explore their advantages and limitations compared to conventional autopsy. PMCT has already become a routine investigation in several centres, and different techniques have been developed to better visualise the vascular system and organ parenchyma in PMCT. In contrast, the use of PMMR is still limited due to practical issues, and research is now starting in the field of PMMR angiography. This article gives an overview of the problems in post-mortem contrast media application, the various classic and modern techniques, and the issues to consider by using different media.

Adult post-mortem imaging in traumatic and cardiorespiratory death and its relation to clinical radiological imaging

The use of post-mortem imaging is expanding throughout the world with increasing use of advanced imaging techniques, such as contrast-enhanced CT and MRI. The questions asked of post-mortem imaging are complex and can be very different, for example for natural sudden death investigation will focus on the cause, whereas for trauma the cause of death is often clear, but injury patterns may be very revealing in investigating the background to the incident. Post-mortem imaging is different to clinical imaging regarding both the appearance of pathology and the information required, but there is much to learn from many years of clinical research in the use of these techniques. Furthermore, it is possible that post-mortem imaging research could be used not only for investigating the cause of death but also as a model to conduct clinically relevant research. This article reviews challenges to the development of post-mortem imaging for trauma, identification and cardiorespiratory death, and how they may be influenced by current clinical thinking and practice.

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.

Advances in post-mortem CT-angiography

Performing a post-mortem multidetector CT (MDCT) scan has already become routine in some institutes of forensic medicine. To better visualize the vascular system, different techniques of post-mortem CT-angiography have been explored, which can essentially be divided into partial- and whole-body angiography techniques. Probably the most frequently applied technique today is the so-called multiphase post-mortem CT-angiography (MPMCTA) a standardized method for investigating the vessels of the head, thorax and abdomen. Different studies exist, describing its use for medicolegal investigations, and its advantages as well as its artefacts and pitfalls. With the aim to investigate the performance of PMCTA and to develop and validate techniques, an international working group was created in 2012 called the "Technical Working Group Post-mortem Angiography Methods" (TWGPAM). Beyond its primary perspective, the goals of this group include creating recommendations for the indication of the investigation and for the interpretation of the images and to distribute knowledge about PMCTA. This article provides an overview about the different approaches that have been developed and tested in recent years and an update about ongoing research in this field. It will explain the technique of MPMCTA in detail and give an outline of its indications, application, advantages and limitations.

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.

Type II DeBakey dissection with complete aortic rupture visualized by unenhanced postmortem imaging

We present postmortem computed tomography (pmCT) as well as postmortem magnetic resonance (pmMR) imaging findings in a case of type II DeBakey aortic dissection with a complete rupture of the ascending aorta compared to the findings obtained at forensic autopsy. PmCT only allowed a presumptive diagnosis of aortic dissection based on an anterior mediastinal enlargement. However, at pmMR the dissection including the aortic rupture was clearly visible. Visualization was realized in an unenhanced manner without the need for postmortem angiography.

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

PURPOSE

To determine the potential of minimally invasive postmortem computed tomographic (CT) angiography combined with image-guided tissue biopsy of the myocardium and lungs in decedents who were thought to have died of acute chest disease and to compare this method with conventional autopsy as the reference standard.

MATERIALS AND METHODS

The responsible justice department and ethics committee approved this study. Twenty corpses (four female corpses and 16 male corpses; age range, 15-80 years), all of whom were reported to have had antemortem acute chest pain, were imaged with postmortem whole-body CT angiography and underwent standardized image-guided biopsy. The standard included three biopsies of the myocardium and a single biopsy of bilateral central lung tissue. Additional biopsies of pulmonary clots for differentiation of pulmonary embolism and postmortem organized thrombus were performed after initial analysis of the cross-sectional images. Subsequent traditional autopsy with sampling of histologic specimens was performed in all cases. Thereafter, conventional histologic and autopsy reports were compared with postmortem CT angiography and CT-guided biopsy findings. A Cohen κ coefficient analysis was performed to explore the effect of the clustered nature of the data.

RESULTS

In 19 of the 20 cadavers, findings at postmortem CT angiography in combination with CT-guided biopsy validated the cause of death found at traditional autopsy. In one cadaver, early myocardial infarction of the papillary muscles had been missed. The Cohen κ coefficient was 0.94. There were four instances of pulmonary embolism, three aortic dissections (Stanford type A), three myocardial infarctions, three instances of fresh coronary thrombosis, three cases of obstructive coronary artery disease, one ruptured ulcer of the ascending aorta, one ruptured aneurysm of the right subclavian artery, one case of myocarditis, and one pulmonary malignancy with pulmonary artery erosion. In seven of 20 cadavers, CT-guided biopsy provided additional histopathologic information that substantiated the final diagnosis of the cause of death.

CONCLUSION

Postmortem CT angiography combined with image-guided biopsy, because of their minimally invasive nature, have a potential role in the detection of the cause of death after acute chest pain.

Demonstration of liver metastases on postmortem whole body CT angiography following inadvertent systemic venous infusion of the contrast medium

An 86-year-old woman was hospitalized for breathlessness and a large right-sided pleural effusion. Approximately 1 h after thoracentesis, she developed a hemothorax resulting in hypotension and death. Routine postmortem CT scanning showed a large volume right hemothorax and a markedly enlarged liver. In an attempt to determine the origin of bleeding prior to autopsy, a postmortem CT angiogram was performed. Following inadvertent cannulation of the left long saphenous vein and infusion of ∼1,700 mL of a polyethylene glycol 200 and iodine-based radiographic contrast solution into systemic veins using a mechanical pump, CT scanning revealed a dense hepatic "parenchogram" containing multiple large, filling defects indicative of metastases. These were confirmed at autopsy. Microscopic evaluation of the liver using hematoxylin and eosin staining showed marked histological artifact characterized by centrilobular sinusoidal expansion although histology of the adenocarcinoma metastases was typical and apparently unaffected by the contrast solution. Postmortem CT angiography using an aqueous radiographic contrast agent in the so-called venous phase seems to be useful for the identification of hepatic parenchymal metastatic disease although it does cause histological artifact.

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.

Postmortem imaging-guided biopsy as an adjuvant to minimally invasive autopsy with CT and postmortem angiography: a feasibility study

OBJECTIVE

Although postmortem CT suffices for diagnosing most forms of traumatic death, the examination of natural death is, to date, very difficult and error prone. The introduction of postmortem angiography has led to improved radiologic diagnoses of natural deaths. Nevertheless, histologic changes to tissues, an important aspect in traditional examination procedures, remain obscure even with CT and CT angiography. For this reason, we examined the accuracy of a minimally invasive procedure (i.e., CT angiography combined with biopsy) in diagnosing major findings and the cause of death in natural deaths.

MATERIALS AND METHODS

We examined 20 bodies in a minimally invasive fashion-namely, native CT, CT angiography, and biopsy-and compared the results to those obtained at subsequent autopsy and histologic analysis.

RESULTS

Regarding the major findings and the cause of death, the minimally invasive examination showed almost identical results in 18 of 20 cases. In one case, the severity of a cardiac ischemia was underestimated; in another case, the iliopsoas muscles were not biopsied, thus missing the diagnosis of discoid muscle necrosis and therefore a death due to hypothermia.

CONCLUSION

In light of increasing objections of the next of kin toward an autopsy and the necessity for medical examiners to assess the manner and cause of death, we think that the minimally invasive procedure described here may present a viable compromise in selected cases.

Combination of post mortem coronary angiography, corrosion cast method and multi-slice computed tomography (MSCT) for diagnostic improvement in pathology and forensics

In recent years, post mortem multi-slice computed tomography (MSCT) is increasingly applied for forensic and pathologic examination. However, classical dissection remains dominant in everyday practice. Lack of quantifiable data on the coronary system has become a disadvantageous attribute of traditional autopsy. Therefore, post mortem MSCT angiography was performed in 80 ex corpo hearts with the aim of improving the accuracy and quantitative documentation of pathologic and forensic diagnoses of coronary artery disease (CAD). Hearts were perfused by introducing a new oily or synthetic resin, or using both contrast materials successively. Then the perfused organs were processed for imaging. Detailed angiographic analysis enabled us to localize, map and quantify coronary calcifications, stenoses, and to characterize the types of atherosclerotic plaques. Significant early or late complications of widely used percutaneous coronary interventions (PCI) and coronary bypass surgery (CABS) could be revealed using CT analysis. Furthermore, by using our oily contrast material and CT imaging, we could identify and visualize the clinically important small caliber nodal arteries (diameter 0.4–2.0 mm). The present work suggests that post mortem CT angiography and post-processing of the data may improve the quality of pathologic and forensic diagnosis. Our collection of coronary casts including digital data are available for further analysis.

Abdominal trauma--sensitivity and specificity of postmortem noncontrast imaging findings compared with autopsy findings

OBJECTIVE

The aim of the study was to determine the sensitivity and specificity for typical abdominal injuries after major blunt trauma in postmortem multislice computed tomography (MSCT) and magnetic resonance imaging (MRI).

MATERIAL

Thirty-four cases of accidental death underwent postmortem pre-autopsy MSCT and MRI. The imaging findings were correlated with the autopsy findings.

RESULTS

Sensitivity and specificity for liver injury in computed tomography (CT) alone were 53% and 84%. In MRI, a sensitivity of 58% and a specificity of 46% were found. CT and MRI together (when either one was positive, liver-injury was considered) had a sensitivity of 73% and a specificity of 63%. For major liver lacerations (grades II-VI) a slightly higher sensitivity of 81% and a better specificity of 100% were noted. CT and MRI together showed a sensitivity of 50% for injuries of the spleen, specificity was 89%. CT and MRI together had a sensitivity of only 25% for trauma of the kidney, but a specificity of 100%.

CONCLUSION

A lot of cases with small organ injuries (such as superficial liver-laceration) seemed that could not be found by MSCT or by MRI, leading to a rather low sensitivity. Nevertheless, most of the life-threatening liver injuries could be detected, which is essential in forensic pathology.

Whole body postmortem angiography with a high viscosity contrast agent solution using poly ethylene glycol as contrast agent dissolver

Postmortem minimal invasive angiography has already been implemented to support virtual autopsy examinations. An experimental approach in a porcine model to overcome an initially described artificial tissue edema artifact by using a poly ethylene glycol (PEG) containing contrast agent solution showed promising results. The present publication describes the first application of PEG in a whole corpse angiographic CT examination. A minimal invasive postmortem CT angiography was performed in a human corpse utilizing the high viscosity contrast agent solution containing 65% of PEG. Injection was carried out via the femoral artery into the aortic root in simulated cardiac output conditions. Subsequent CT scanning delivered the 3D volume data of the whole corpse. Visualization of the human arterial anatomy was excellent and the contrast agent distribution was generally limited to the arterial system as intended. As exceptions an enhancement of the brain, the left ventricular myocardium and the renal cortex became obvious. This most likely represented the stage of centralization of the blood circulation at the time of death with dilatation of the precapillary arterioles within these tissues. Especially for the brain this resulted in a distinctively improved visualization of the intracerebral structures by CT. However, the general tissue edema artifact of postmortem minimal invasive angiography examinations could be distinctively reduced.

Postmortem imaging of blunt chest trauma using CT and MRI: comparison with autopsy

OBJECTIVE

Postmortem examination of chest trauma is an important domain in forensic medicine, which is today performed using autopsy. Since the implementation of cross-sectional imaging methods in forensic medicine such as computed tomography (CT) and magnetic resonance imaging (MRI), a number of advantages in comparison with autopsy have been described. Within the scope of validation of cross-sectional radiology in forensic medicine, the comparison of findings of postmortem imaging and autopsy in chest trauma was performed.

METHODS

This retrospective study includes 24 cases with chest trauma that underwent postmortem CT, MRI, and autopsy. Two board-certified radiologists, blind to the autopsy findings, evaluated the radiologic data independently. Each radiologist interpreted postmortem CT and MRI data together for every case. The comparison of the results of the radiologic assessment with the autopsy and a calculation of interobserver discrepancy was performed.

RESULTS

Using combined CT and MRI, between 75% and 100% of the investigated findings, except for hemomediastinum (70%), diaphragmatic ruptures (50%; n=2) and heart injury (38%), were discovered. Although the sensitivity and specificity regarding pneumomediastinum, pneumopericardium, and pericardial effusion were not calculated, as these findings were not mentioned at the autopsy, these findings were clearly seen radiologically. The averaged interobserver concordance was 90%.

CONCLUSION

The sensitivity and specificity of our results demonstrate that postmortem CT and MRI are useful diagnostic methods for assessing chest trauma in forensic medicine as a supplement to autopsy. Further radiologic-pathologic case studies are necessary to define the role of postmortem CT and MRI as a single examination modality.

Postmortem whole-body CT angiography: evaluation of two contrast media solutions

OBJECTIVE

The objective of our study was to establish a standardized procedure for postmortem whole-body CT-based angiography with lipophilic and hydrophilic contrast media solutions and to compare the results of these two methods.

MATERIALS AND METHODS

Minimally invasive postmortem CT angiography was performed on 10 human cadavers via access to the femoral blood vessels. Separate perfusion of the arterial and venous systems was established with a modified heart-lung machine using a mixture of an oily contrast medium and paraffin (five cases) and a mixture of a water-soluble contrast medium with polyethylene glycol (PEG) 200 in the other five cases. Imaging was executed with an MDCT scanner.

RESULTS

The minimally invasive femoral approach to the vascular system provided a good depiction of lesions of the complete vascular system down to the level of the small supplying vessels. Because of the enhancement of well-vascularized tissues, angiography with the PEG-mixed contrast medium allowed the detection of tissue lesions and the depiction of vascular abnormalities such as pulmonary embolisms or ruptures of the vessel wall.

CONCLUSION

The angiographic method with a water-soluble contrast medium and PEG as a contrast-agent dissolver showed a clearly superior quality due to the lack of extravasation through the gastrointestinal vascular bed and the enhancement of soft tissues (cerebral cortex, myocardium, and parenchymal abdominal organs). The diagnostic possibilities of these findings in cases of antemortem ischemia of these tissues are not yet fully understood.

Virtual autopsy using imaging: bridging radiologic and forensic sciences. A review of the Virtopsy and similar projects

The transdisciplinary research project Virtopsy is dedicated to implementing modern imaging techniques into forensic medicine and pathology in order to augment current examination techniques or even to offer alternative methods. Our project relies on three pillars: three-dimensional (3D) surface scanning for the documentation of body surfaces, and both multislice computed tomography (MSCT) and magnetic resonance imaging (MRI) to visualise the internal body. Three-dimensional surface scanning has delivered remarkable results in the past in the 3D documentation of patterned injuries and of objects of forensic interest as well as whole crime scenes. Imaging of the interior of corpses is performed using MSCT and/or MRI. MRI, in addition, is also well suited to the examination of surviving victims of assault, especially choking, and helps visualise internal injuries not seen at external examination of the victim. Apart from the accuracy and three-dimensionality that conventional documentations lack, these techniques allow for the re-examination of the corpse and the crime scene even decades later, after burial of the corpse and liberation of the crime scene. We believe that this virtual, non-invasive or minimally invasive approach will improve forensic medicine in the near future.