The degradation of collagen in submerged bones, analysed by ImageJ® and Orbit®, for the estimation of the post-mortem interval (PMI) and the post-mortem submersion interval (PMSI)

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ABSTRACT

The estimation of the post-mortem submersion interval (PMSI) of skeletal remains can provide critical information to forensic investigations, contributing to various aspects such as identification. A fundamental aspect of the PMSI estimation in bone is the degradation of collagen, the most abundant organic component. This degradation can be assessed using various analytical techniques, including the digital analysis of images taken from histological slides. Two open-source software for image digital analysis, ImageJ® and Orbit®, provide novice-friendly and accessible technology to a broad audience of forensic practitioners. However, the absence of established procedures can challenge the consistency of the interpretation of the results, especially between observers. The principal aim of this study was to compare the efficacy of ImageJ® and Orbit® in quantifying the degradation of collagen in images taken from histological slides of mammalian non-human bones submerged for 4 months to 2 years. Despite the inconsistency in the outcomes of intraobserver vs. interobserver testing, this research has demonstrated the promising potential of digital histology. It has also identified the need for further investigation, particularly focusing on the usability of ImageJ® and the refinement of the Orbit® workflow.

KEYWORDS:

• Collagen
• ImageJ®
• Orbit®
• picrosirius red
• remote consultations

Acknowledgments

The authors express sincere gratitude to the Australian and New Zealand Forensic Science Society (ANZFSS) for the National Symposium Award, which has enabled Laura to participate in the joint International Association of Forensic Sciences (IAFS) and ANZFSS Symposium in Sydney, Australia, in November 2023. Furthermore, the authors thank Murdoch University (MU) for funding this research project, and Bin Ma (Murdoch University) for the assistance with image processing software.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

The work was supported by the Australian and New Zealand Forensic Science Society (ANZFSS) [National Symposium Award]; Internal funding.