Rigor mortis at the myocardium investigated by post-mortem magnetic resonance imaging

Morphological and Genetic Aspects for Post-Mortem Diagnosis of Hypertrophic Cardiomyopathy: A Systematic Review

Hypertrophic cardiomyopathy (HCM) is one of the most common genetic cardiovascular diseases, and it shows an autosomal dominant pattern of inheritance. HCM can be clinically silent, and sudden unexpected death due to malignant arrhythmias may be the first manifestation. Thus, the HCM diagnosis could be performed at a clinical and judicial autopsy and offer useful findings on morphological features; moreover, it could integrate the knowledge on the genetic aspect of the disease. This review aims to systematically analyze the literature on the main post-mortem investigations and the related findings of HCM to reach a well-characterized and stringent diagnosis; the review was performed using PubMed and Scopus databases. The articles on the post-mortem evaluation of HCM by gross and microscopic evaluation, imaging, and genetic test were selected; a total of 36 studies were included. HCM was described with a wide range of gross findings, and there were cases without morphological alterations. Myocyte hypertrophy, disarray, fibrosis, and small vessel disease were the main histological findings. The post-mortem genetic tests allowed the diagnosis to be reached in cases without morpho-structural abnormalities; clinical and forensic pathologists have a pivotal role in HCM diagnosis; they contribute to a better definition of the disease and also provide data on the genotype-phenotype correlation, which is useful for clinical research.

Radiographic and anatomical morphometric assessments of heart size in presumed healthy pet guinea pigs

Cardiac disease in guinea pigs has been reported in the literature; however, reference intervals for normal radiographic heart size obtained using objective measurement methods have not been provided for this species. The aim of this prospective, reference interval study was to describe cardiac dimensions in presumed healthy guinea pigs using the vertebral heart scale (VHS) from thoracic radiographs, as described for dogs and cats. Furthermore, an anatomical study was carried out to compare the radiographic and anatomical findings. Thoracic radiographs were acquired in right lateral recumbency for 30, client‐owned, conscious, presumed healthy guinea pigs and radiographs were acquired in left lateral recumbency for 10 presumed healthy guinea pigs as comparisons. The influence of sex, age, body weight (BW), and recumbency on the VHS and absolute cardiac measurements was investigated. The median (interquartile range; IQR) VHS was 7.4 (7.1‐7.6). No differences emerged between the VHS measured in right versus left lateral recumbency (P = .41) or between sexes (P = .16). The VHS values were not influenced by age (P = .53) or BW (P = .26). The anatomical study was carried out on 10 guinea pig cadavers, and in situ and ex situ cardiac measurements were taken using a caliper. A median (IQR) 7.5 (7.2‐8.0) VHS was assessed by this anatomical study. The reference intervals provided should be useful tools in the future for the radiographic interpretation of cardiac size in guinea pigs in clinical practice.

Technical Note: Post-burial alteration of bones: Quantitative characterization with solid-state 1H MAS NMR

The identification of markers of the modifications occurring in human bones after death and of the sedimentary and post-sedimentary processes affecting their state of preservation, is of interest for several scientific disciplines. A new index, obtained from spectral deconvolution of the 1H MAS NMR spectra of bones, relating the number of organic protons to the amount of hydrogen nuclei in the OH- groups of bioapatite, is proposed as indicator of the state of preservation of the organic fraction. In the osteological material from three different archaeological sites, this index resulted positively correlated with the extent of collagen loss derived from infrared spectroscopy. Its sensitivity to changes in the physical and chemical characteristics of bone allows to identify distinct diagenetic pathways specific to each site and to distinguish different trajectories within the same site.

Morphological variability of the atrioventricular valve cusps in the equine heart

BACKGROUND

The morphometric studies of the atrioventricular valves are still limited in the horse.

OBJECTIVES

To investigate the anatomy of the atrioventricular valves in the horse, focusing on the morphometric features of the valvular leaflets and the tendinous cords. We hypothesised that accessory leaflets occur commonly and exist as independent structures in the atrioventricular valves of the horse.

STUDY DESIGN

Descriptive anatomical study.

METHODS

Twenty normal hearts from slaughtered half-bred horses were used. The cardiac weight and circumference were recorded. The atrioventricular valves were exposed by excision of the atria, and the tricuspid and mitral annular diameters and circumferences were measured; the number of leaflets and tendinous cords for each atrioventricular ostium were then counted. The atrioventricular valves were isolated and the width, height and thickness of each leaflet were measured.

RESULTS

In addition to the principal leaflets, accessory leaflets were identified in 39 of 40 cardiac valves, 2 to 6 accessory leaflets for the mitral valve and 1 to 4 for the tricuspid valve. All the accessory leaflets were separated from the adjacent leaflets at their insertion. They were narrower and thinner than the principal leaflets, and were attached to a single papillary muscle; 95% of the accessory leaflets had two tendinous cords shared with the adjacent leaflets while a minority (34%) had their own specific tendinous cord.

MAIN LIMITATIONS

Lack of signalment data from the study population.

CONCLUSIONS

Supernumerary leaflets occurred commonly in the atrioventricular valves of the horse and appeared as independent structures. The clinical relevance of increased numbers of commissures that result from accessory leaflets and their relationship with valvular regurgitation are currently unknown.

Post-Mortem Cardiac Magnetic Resonance for the Diagnosis of Hypertrophic Cardiomyopathy

Background: Post-mortem cardiac magnetic resonance (PMCMR) is an emerging tool supporting forensic medicine for the identification of the causes of cardiac death, such as hypertrophic cardiomyopathy (HCM). We proposed a new method of PMCMR to diagnose HCM despite myocardial rigor mortis. Methods: We performed CMR in 49 HCM patients, 30 non-HCM hypertrophy, and 32 healthy controls. In cine images, rigor mortis was simulated by the analysis of the cardiac phase corresponding to 25% of diastole. Left ventricular mass, mean, and standard deviation (SD) of WT, maximal WT, minimal WT, and their difference were compared for the identification of HCM. These parameters were validated at PMCMR, evaluating eight hearts with HCM, 10 with coronary artery disease, and 10 with non-cardiac death. Results: The SD of WT with a cut-off of > 2.4 had the highest accuracy to identify HCM (AUC 0.95, 95% CI = 0.89–0.98). This was particularly evident in the female population of HCM (AUC=0.998), with 100% specificity (95% CI = 85–100%) and 96% sensitivity (95% CI = 79–99%). Using this parameter, at PMCMR, all of the eight patients with HCM were correctly identified with no false positives. Conclusions: PMCMR allows identification of HCM as the cause of sudden death using the SD of WT > 2.4 as the diagnostic parameter.

The Accuracy of Left Ventricular and Left Atrial Volumetry Using 64-Slice Computed Tomography: In Vitro Validation Study With Human Cardiac Cadaveric Casts

OBJECTIVE

We aimed to validate the accuracy of imaging of left atrial and ventricular volumes using cardiac cadaveric silicone casts.

METHODS

Left atrial (n = 14) and ventricular (n = 15) casts were imaged using 64-slice computed tomography (CT). Water displacement (WD) of cardiac casts was used as the gold standard for volume measurements.

RESULTS

Compared with WD, CT resulted in slightly higher left atrial and ventricular volumes (54 ± 25 vs 56 ± 26 mL [P = 0.003] and 57 ± 47 vs 66 ± 47 mL [P = 0.0001]). Variability between left atrial and ventricular volumes by CT and WD was low (coefficients of variation [CVs], 4% [intraclass correlation coefficient {ICC}, 0.99] and 12% [ICC, 0.97]). Intraobserver variability of CT was low for both the left atrium and the left ventricle (CVs, 1% [ICC, 1.00] and 4% [ICC, 1.00]).

CONCLUSIONS

Cardiac CT is both accurate and reproducible in assessment of left ventricular and atrial chamber volumes.

Early time-related course of image findings in postmortem MRI: Typical findings and observer agreement in a porcine model

PURPOSE

To assess early time-related image findings in postmortem magnetic resonance imaging (MRI) and to evaluate observer agreement in a porcine model.

MATERIAL AND METHODS

Three pigs were examined by MRI at 15 different time points in the first 36h after death. Two observers independently recorded the postmortem interval (PMI) to the appearance of fluid collection (pleural space, interlobar and interlobular pulmonary fissures and hepatic interlobar fissures), gas accumulation (intrahepatic and intracardial) and blood clotting (aorta and intrahepatic venous vessels). Cohen's Kappa statistics and intraclass correlation coefficient (ICC) were used to evaluate intra- and interobserver agreement.

RESULTS

Intrahepatic gas was evident after 12, 17 and 30h. Also, intracardiac gas was present in all animals. However, no chronological appearance has been observed. Blood clotting in the hepatic vein was observed within 3min, aortic clotting with a delay of 2-12h after death. Interlobular pulmonary fluid (median PMI: 2h, range 2-2h), pleural effusion (median PMI: 10.5h, range 9-12h) and hepatic interlobar fissure fluid (median PMI: 11.5h, range 11-12h) displayed a chronological appearance pattern. Qualitative and quantitative detection of most postmortem findings showed excellent intra- and interobserver agreement with Kappa values>0.8 or ICC>0.75.

CONCLUSION

Pulmonary and hepatic fissural fluid collection as well as intravasal gas accumulation are early time-related image findings in postmortem MRI. The chronological appearance of these findings can be assessed with excellent observer agreement in a porcine model.

Detection and differentiation of early acute and following age stages of myocardial infarction with quantitative post-mortem cardiac 1.5T MR

Recently, quantitative MR sequences have started being used in post-mortem imaging. The goal of the present study was to evaluate if early acute and following age stages of myocardial infarction can be detected and discerned by quantitative 1.5T post-mortem cardiac magnetic resonance (PMCMR) based on quantitative T1, T2 and PD values. In 80 deceased individuals (25 female, 55 male), a cardiac MR quantification sequence was performed prior to cardiac dissection at autopsy in a prospective study. Focal myocardial signal alterations detected in synthetically generated MR images were MR quantified for their T1, T2 and PD values. The locations of signal alteration measurements in PMCMR were targeted at autopsy heart dissection and cardiac tissue specimens were taken for histologic examinations. Quantified signal alterations in PMCMR were correlated to their according histologic age stage of myocardial infarction. In PMCMR seventy-three focal myocardial signal alterations were detected in 49 of 80 investigated hearts. These signal alterations were diagnosed histologically as early acute (n=39), acute (n=14), subacute (n=10) and chronic (n=10) age stages of myocardial infarction. Statistical analysis revealed that based on their quantitative T1, T2 and PD values, a significant difference between all defined age groups of myocardial infarction can be determined. It can be concluded that quantitative 1.5T PMCMR quantification based on quantitative T1, T2 and PD values is feasible for characterization and differentiation of early acute and following age stages of myocardial infarction.