Post-mortem imaging in sudden death cases due to arterial or cardiac hemorrhage

The authors present cases of natural death due to arterial or cardiac hemorrhage evaluated using both conventional autopsy examination and post-mortem imaging, including post-mortem computed tomography angiography (PMCTA). Visualization based on CT scan acquisition are presented combined with the results of macroscopic and microscopic examination. Based on cases presented it can be seen that in selected cases PMCTA might be a sufficient method of examination while combined with conventional external examination and toxicological investigation; however, in investigations of alleged medical malpractice cases, histopathological examination of specimens seems to be necessary. There are no doubts that post-mortem imaging differs from clinical examination. As we consider the history and the output of clinical imaging methods, there are plenty of challenges awaiting in the field of post-mortem imaging. Die Autoren präsentieren natürliche Todesfälle aufgrund arterieller oder kardialer Blutungen, die sowohl durch eine konventionelle Autopsie als auch mittels postmortaler Bildgebung, einschließlich postmortaler Computertomographie-Angiographie (PMCTA), beurteilt wurden. Die CT-basierte Visualisierung wird vorgestellt, in Kombination mit den Ergebnissen makroskopischer und mikroskopischer Untersuchungen. Anhand der vorgestellten Fälle wird deutlich, dass die PMCTA in selektierten Fällen als Untersuchungsverfahren ausreichend sein kann, wenn sie mit der konventionellen externen Untersuchung und der toxikologischen Erhebung kombiniert wird; jedoch scheint bei der Untersuchung von Fällen, in denen angeblich ein ärztlicher Behandlungsfehler vorliegt, die histopathologische Untersuchung von Proben notwendig zu sein. Es besteht kein Zweifel, dass sich die postmortale Bildgebung von der klinischen Untersuchung unterscheidet. Betrachtet man die Entwicklung und die Ergebnisse der klinischen Bildgebungsverfahren, so wird es zahlreiche Herausforderungen im Bereich der postmortalen Bildgebung geben.


Introduction
During the last decade post-mortem imaging has strengthened its position giving the opportunity for a revival of medico-legal autopsy examination. The milestones of this examination technique were set up by publications about Virtopsy ® [1] as well as the second edition of Brogdon's forensic radiology [2]. Conventional autopsy replacement ideas seem to be restricted to compatibility between conventional and modern methods of examination heading to opportunities for higher level of objectivity [3]. Due to relatively good availability and moderate costs, the most popular technology applied in modern postmortem imaging is post-mortem computed tomography (PMCT); however, unenhanced PMCT in violent and natural death cases may be insufficient similarly to conventional autopsy techniques in showing the actual source of bleeding related to the damage of blood vessels and even worse referring to evaluation of internal organ injuries. The addition of contrast agent (CA) administration provides the opportunity for successful supplementation of this examination technique into PMCT angiography (PMCTA).

Material and methods
In everyday practice of the authors' Department of Forensic Medicine, PMCT acquisitions are performed in almost every case directed to the department. With respect to the PMCTA, we implemented two main indications for this examina-tion: victims of potential homicide especially due to sharp force trauma and cases screened by the PMCT with positive findings showing high possibility of internal bleeding. As a member of the Technical Working Group Postmortem  prospects for PMCTA evaluation were taken into consideration, including cases of natural deaths due to hemorrhage. In the current paper we present the results of both conventional and PMCT/ PMCTA evaluation of five cases, including four ruptured aneurysms (one at the base of the brain, one of the abdominal aorta and two dissecting aneurysms of the thoracic aorta) and one cardiac rupture at the site of myocardial infarction. The cases included adults of both sexes, aged from 41 to 75 years old. The CT data acquisition was completed within 1-5 days after death. All cases were scanned using 16-layer tomography (Somatom Emotion, Siemens, Munich, Germany, kVp 130, mAs 50 and 240), reconstructed slice thickness 0.75 and 1.5, collimation 16 × 0.6, and pitch 0.85 and 0.55. Before CA administration all cadavers were examined using unenhanced PMCT as well as external conventional examination and material sampling for toxicological examination was performed. As a TWGPAM member, we applied whole-body examination utilizing the standardized CA protocol with the use of 6% oily liquid solution of Angiofil ® (Fumedica, Muri, Switzerland), administered to femoral vessels. After imaging, a complete conventional internal autopsy examination was performed. Macroscopic examination was accompanied by histology with hematoxylin-eosin(H&E)staining ofthe heart, brain, lungs, liver, kidneys as well as the regions of hemorrhage (arterial and cardiac walls). The PMCT/PMCTA acquisition results were evaluated by two forensic pathologists with 9 years of experience in such examination and evaluation using the open source Digital Imaging and Communication (DICOM) viewer, OsiriX (Pixmeo SARL, Bernex, Switzerland, version 5.0.2), including the analysis of two-dimensional (2D) slices, multiplanar reformatted (MPR) images and formation of three-dimensional (3D) im-ages by volume-rendered (VRT) reconstructions.

Results
The . Figs. 1, 2, 3, 4 und 5 show the results of both post-mortem imaging and conventional methods aimed at the source of bleeding/triggering cause of death.

Discussion
The PMCTA technique has only approximately 10 years of history of utilization for forensic pathology purposes [5]. An increasing number of forensic medicine institutes are using the PMCTA examination technique. Different methods of approach were presented, referring to targeted examination of selected regions of the deceased person [6,7], with the attempts of validation of methods in comparison to microscopic [8] and conventional autopsy examinations [9]. Apart from different causes of vascular damage in violent and natural death cases, there are other changes referring to blood vessel pathology taken into consideration, including diagnosis of pulmonary embolism [10], coronary thrombosis, and different aspects of coronary artery disease [11][12][13] including the possibility of myocardial changes visible after CA administration. Vascular changes at different locations [14] and due to specific illnesses [15] were reported. The use of PMCTA, at first aimed only at examination of bodies of deceased adults, has been introduced for other cases, even with problematic technical issues [16]. There are also reports referring to evaluation and visualization in cases after medical interventions related to the heart and great vessels [17,18]. The publications are aimed not only at diagnostic efficiency but also present different methods of CA administration [10,19,20] with the propositions of standardized protocols [4,21]. As we understand that there are no universal "remedies" for evaluation of all cases, the advances and limitations in the development of examination methods with the use of administration of CA to cadavers were discussed [22,23]. A valuable achievementis thatthe presentation of cases referring to post-mortem imaging results are reaching scientific journals not only dedicated to forensic pathologists/radiologists, but also clinical disciplines [24], which may give the opportunity for better understanding of the value of post-mortem diagnosis for evaluation of clinical problems. Recent publications provide evidence that PM-CTA may give forensic post-mortem examination additional strength [4]. Based on the cases presented in the current paper we may even claim that the PM-CTA in selected cases might be the sufficient way of examination while combined with conventional external examination and toxicological sampling (investigation); however, histopathological examination of specimens (at least internal organs) seems to be necessary in cases of alleged medical error: for example, it may be crucial for the estimation of timing of critical changes (e.g. ruptures and necrosis).
At the present time there are no doubts that post-mortem imaging differs from

Abstract
The authors present cases of natural death due to arterial or cardiac hemorrhage evaluated using both conventional autopsy examination and post-mortem imaging, including post-mortem computed tomography angiography (PMCTA). Visualization based on CT scan acquisition are presented combined with the results of macroscopic and microscopic examination. Based on cases presented it can be seen that in selected cases PMCTA might be a sufficient method of examination while combined with conventional external examination and toxicological investigation; however, in investigations of alleged medical malpractice cases, histopathological examination of specimens seems to be necessary. There are no doubts that post-mortem imaging differs from clinical examination. As we consider the history and the output of clinical imaging methods, there are plenty of challenges awaiting in the field of post-mortem imaging.

Schlüsselwörter
Postmortale Untersuchung · PMCTA · Aneurysmaruptur · Herzruptur · Visualisierung  clinical examination [25]. As we consider the history and the output of clinical imaging methods, there are plenty of challenges awaiting in the field of postmortem imaging [26].