Tissue sample analysis for post mortem determination of brain edema

Melanie Bauer; Nikolaus Deigendesch; Holger Wittig; Eva Scheurer; Claudia Lenz

doi:10.1016/j.forsciint.2021.110808

Tissue sample analysis for post mortem determination of brain edema

Forensic Sci Int. 2021 Apr 29:323:110808. doi: 10.1016/j.forsciint.2021.110808. Online ahead of print.

Authors

Melanie Bauer¹, Nikolaus Deigendesch², Holger Wittig³, Eva Scheurer³, Claudia Lenz³

Affiliations

¹ Institute of Forensic Medicine, Department of Biomedical Engineering, University of Basel, Basel, Switzerland; Institute of Forensic Medicine, Health Department Basel-Stadt, Basel, Switzerland. Electronic address: melanie.bauer@unibas.ch.
² Institute of Medical Genetics and Pathology, University Hospital Basel, University of Basel, Basel, Switzerland.
³ Institute of Forensic Medicine, Department of Biomedical Engineering, University of Basel, Basel, Switzerland; Institute of Forensic Medicine, Health Department Basel-Stadt, Basel, Switzerland.

PMID: 33971505
DOI: 10.1016/j.forsciint.2021.110808

Abstract

The post mortem evaluation of a brain edema is routinely performed by pathologists based on the macroscopic signs during autopsy. This method represents the current gold standard, but is subjective and observer dependent. Therefore, three post mortem evaluation methods of brain samples were analyzed in this work: histology, wet-dry weight and normalized cerebral weight, which was described in 2020 by Bauer et al. Tissue samples from six different regions of 34 brains were collected and examined both by rating of histological slides and by measuring the water content by using a drying oven. The rating of the histological slides, stained with hematoxylin and eosin, was performed by two pathologists independently. For the water content, the wet weight and the dry weight of each sample were set in relation. The normalized cerebral weight was calculated by dividing the brain weight by the brain volume, which were both determined during autopsy and in computed tomography images, respectively. A fair to moderate interrater agreement was obtained for the histologic evaluation and a significant correlation was present between one rater and the wet-dry weight and the normalized cerebral weight method. When classifying according to the gold standard, a significant difference was detected between the edematous and nonedematous cases by using the wet-dry weight method in the cerebral cortex and by using the normalized cerebral weight method. However, the significant correlations and group differences were limited to the aforementioned results. In conclusion, both the histological and the wet-dry weight method show limited benefits for the classification of brain edema and the histology analysis is highly observer dependent. The normalized cerebral weight method, however, reveals a significant effect between the edematous and nonedematous cases when classifying according to the gold standard. Therefore, we suggest to apply this method for the assessment of brain edema since it is objective and rater independent. Nevertheless, the exact evaluation of brain edema remains a challenging task, especially due to the continuous transition between no edema and edema.

Keywords: Brain edema; Forensic medicine; Forensic neuropathology; Normalized cerebral weight; Post mortem; Wet-dry weight.