Ex situ heart magnetic resonance imaging and angiography: feasibility study for forensic purposes

Forensic significance of intracardiac expressions of Nrf2 in acute myocardial ischemia

When exposed to oxidative and electrophilic stress, a protective antioxidant response is initiated by nuclear factor erythroid 2-related factor 2 (Nrf2). However, the extent of its importance in the forensic diagnosis of acute ischemic heart diseases (AIHD), such as myocardial infarction (MI), remains uncertain. On the other hand, immunohistochemical analyses of fibronectin (FN) and the terminal complement complex (C5b-9) prove valuable in identifying myocardial ischemia that precedes necrosis during the postmortem diagnosis of sudden cardiac death (SCD). In this study, we investigated the immunohistochemical levels of Nrf2, FN, and C5b-9 in human cardiac samples to explore their forensic relevance for the identification of acute cardiac ischemia. Heart samples were obtained from 25 AIHD cases and 39 non-AIHD cases as controls. Nrf2 was localized in the nuclei of cardiomyocytes, while FN and C5b-9 were detected in the myocardial cytoplasm. The number of intranuclear Nrf2 positive signals in cardiomyocytes increased in AIHD cases compared to control cases. Additionally, the grading of positive portions of cardiac FN and C5b-9 in the myocardium was also significantly enhanced in AIHD, compared to controls. Collectively, these results indicate that the immunohistochemical investigation of Nrf2 combined with FN, and/or C5b-9 holds the potential for identifying early-stage myocardial ischemic lesions in cases of SCD.

Sudden Cardiac Death and Ex-Situ Post-Mortem Cardiac Magnetic Resonance Imaging: A Morphological Study Based on Diagnostic Correlation Methodology

During the last years, post-mortem imaging has gradually been assumed within research in the field of forensic pathology. This role appears to be clearly and simply applied in the trauma field with the use of conventional radiography or Post Mortem Computed Tomography (PMCT). Recently, particular attention was paid to cardiovascular imaging using Post Mortem Magnetic Resonance Imaging (PMMRI). The present experimental study aims to: (i) confirm the efficacy of a Post Mortem Cardiac Resonance Imaging (PMCRI) study protocol for the study of human hearts collected during the autopsy; (ii) apply the defined protocol on subjects who died of “SCD (sudden cardiac death)”, to identify alterations that could guide subsequent sampling. Two hearts of healthy subjects (A: male 22 years; B: female 26 years), who died from causes other than SCD were collected and compared to hearts that belonged to SCD individuals (C: male, 47 years old; D: female, 44 years old; E: male; 72 years old). The exams were performed on a 1.5 T scanner (Philips Intera Achieva, Best, the Netherlands) on hearts collected during autopsy and after a 30-day formalin fixation. Two readers analyzed the obtained images blindly and after randomization. From the comparison between the data from imaging and the macroscopic and histological investigations carried out, the present study proved the effectiveness of a PMMRI protocol to study ex-situ hearts. Moreover, it suggested the following semeiology in post-mortem SCD cases: the hyperintense area with indistinct margins in the Short Tau Inversion Recovery (STIR) sequence was linked to edema or area of pathological fibers, whereas the hypointense area in the T2-FFE sequences was linked to fibrosis. PMMRI can provide a valuable benefit to post-mortem investigations, helping to distinctly improve the success rate of histological sampling and investigations, which remains the gold standard in the diagnosis of sudden death.

Sudden Death in Adults: A Practical Flow Chart for Pathologist Guidance

The medico-legal term "sudden death (SD)" refers to those deaths that are not preceded by significant symptoms. SD in apparently healthy individuals (newborn through to adults) represents a challenge for medical examiners, law enforcement officers, and society as a whole. This review aims to introduce a useful flowchart that should be applied in all cases of SD. Particularly, this flowchart mixes the data obtained through an up-to-date literature review and a revision of the latest version of guidelines for autopsy investigation of sudden cardiac death (SCD) in order to support medico-legal investigation. In light of this review, following the suggested flowchart step-by-step, the forensic pathologist will be able to apply all the indications of the scientific community to real cases. Moreover, it will be possible to answer all questions relative to SD, such as: death may be attributable to cardiac disease or to other causes, the nature of the cardiac disease (defining whether the mechanism was arrhythmic or mechanical), whether the condition causing SD may be inherited (with subsequent genetic counseling), the assumption of toxic or illicit drugs, traumas, and other unnatural causes.