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 post-mortem 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 examination: 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 Angiography Methods (TWGPAM) [4] our Department took part in the multicenter study which included mostly violent death cases, referring to sharp force trauma and gunfire injuries; however, other cases with the potential interesting 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 of the 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) images 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.

Fig. 1
figure 1

A 52-year-old female found in bushes under circumstances that suggested sexual assault; however, post-mortem examination excluded any violent cause of death: a thin coronal plane section of the head based on unenhanced PMCT showing signs of both subarachnoid and intraventricular hemorrhage; the arrow shows the location of the possible source of bleeding, b thick coronal plane of the head based on PMCTA in the dynamic phase showing CA extravasation at the base of the right side of the brain, c the autopsy specimen of the arteries at the base of the brain, showing the ruptured aneurysm (arrow) of the right middle cerebral artery (“inferior” view), d microscopic specimen, showing changes of the arterial wall and the aneurysm (H&E × 40)

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Fig. 2
figure 2

A 41-year-old male presenting with complaints of pain in the chest and the back, who had been examined two times (day by day) in hospital, finally discharged home where he died the next day. Post-mortem examination revealed the ruptured dissecting aortic aneurysm, spreading to carotid and iliac arteries, with two areas of rupture in the immediate vicinity of the base of the heart and the aortic arch: a thin axial plane of the thorax based on unenhanced PMCT showing blood inside the pericardial sac, b VRT reconstruction based on PMCTA at the arterial phase showing CA inside both lumens of the dissecting aortic aneurysm as well as CA extravasation into the pericardial sac, right posterior view, c the autopsy specimen showing internal wall of the aortic arch with the rupture and d microscopic specimen, showing dissection of the aortic wall with bleeding (H&E × 40)

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Fig. 3
figure 3

A 55-year-old woman with a history of hypertensive and Graves-Basedow diseases, under systematic medical supervision, collapsed and died unexpectedly. Post-mortem examination revealed widening of the circumference of the ascending aorta (up to 10 cm), the ruptured dissecting aortic aneurysm with two ruptures of the ascending aorta, both diameters approximately 1 cm: a thick axial plane of the thorax based on unenhanced PMCT showing blood inside the pericardial sac, b thin axial plane based on PMCTA at the arterial phase showing dissecting aortic aneurysm, c VRT reconstruction based on PMCTA at the arterial phase showing CA inside both lumens of the dissected aortic aneurysm as well as CA extravasation to the pericardial sac, left anterior view and d autopsy specimen showing dissecting aneurysm of the descending aorta

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Fig. 4
figure 4

A 75-year-old male suffered from pain in the inguinal area and subsequently lower back pain. He had been observed for several hours in hospital and discharged home, where he died on the same day: a thin axial plane of the abdomen based on unenhanced PMCT showing the changes located anteriorly to the spine and at the right side (suggesting bleeding because of ruptured aneurysm), b thin coronal plane based on PMCTA at the arterial phase showing ruptured aneurysm of abdominal aorta with CA extravasation to the right, note the cannulation of femoral vessels at the right side and c VRT reconstruction of the aneurysm based on PMCTA at the arterial phase, showing the leakage (arrow)

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Fig. 5
figure 5

A 56-year-old male without previous treatment died unexpectedly in the street. Forensic autopsy revealed areas of myocardial necrosis (pale red, partially yellowish tinted) of 9 × 3 cm in size, with the double rupture of the posterior wall (each about 1 cm) of the left ventricle at the apical region: a axial plane of the thorax based on unenhanced PMCT showing blood inside the pericardial sac, b, c both based on PMCTA at the arterial phase: thin axial (b) and coronal (c) plane showing CA leakage to the pericardial sac (arrow), d the autopsy specimen showing the apical part of the heart with the rupture (encircled), e the autopsy specimen with the cut in the left ventricle, showing the area of necrosis and rupture (arrow) and f microscopic specimen, showing different stages of necrosis of cardiomyocytes (H&E × 40)

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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 achievement is that the 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 PMCTA may give forensic post-mortem examination additional strength [4]. Based on the cases presented in the current paper we may even claim that the PMCTA 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 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 post-mortem imaging [26].