Current and emerging histomorphometric and imaging techniques for assessingage‐at‐deathand cortical bone quality

Abstract

Bones are dynamic living organs that undergo continual change throughout life. An internal process of tissue renewal, called remodeling, removes mature microscopic packets of bone, and replaces them with new bone in a highly coordinated manner. To date, it remains difficult to directly observe and track individual remodeling events in cortical bone due to the small size of the structures involved. High‐resolution imaging techniques hold the potential to provide novel three‐dimensional information pertaining to changes in bone's microarchitecture, cortical porosity, and the remodeling process. This review critically explores the methodological approaches used historically by researchers to assess the products of remodeling within cortical bone and relate it to age‐at‐death estimation, extending from histology to modern ex vivo imaging modalities, and discusses the growing potential of in vivo imaging. We further provide an introduction to various histological indicators of bone quality and fragility, their forensic relevance, and examples of novel imaging modalities employed for their investigation. The review concludes with an introduction to cutting‐edge in vivo four‐dimensional imaging techniques that include the use of animal models to shed new light on the dynamic nature of bone, and the processes of bone aging and disease. Data gleaned from these new insights will ultimately lead to the development of future histologic age‐estimation methods in forensic anthropology. This article is categorized under: Forensic Anthropology > Age Assessment Forensic Chemistry and Trace Evidence > Emerging Technologies and Methods Forensic Medicine > Imaging Modalities

The professional practice of forensic anthropology: Contemporary developments and cross‐disciplinary applications

“…In assessing the suitability of these methods, it is important that potential variances in the expression of histological features relative to intra-and interelement variation are considered, especially relevant with the refinement of 3D approaches and micro-CT imaging, compare with, García-Donas et al ( 2016), Maggiano et al (2020), and Andronowski and Cole (2021). For example, Haversian systems and canals are known to be larger in long and irregular, relative to flat bones (Cummaudo et al, 2020), with clear variances in osteon morphology relative to skeletal maturity (Britz et al, 2009).…”

“…Histological age estimations are primarily based in quantifying size ratios between osteons and Haversian canals, for example, measurement of perimeter, diameter or total area, and/or measurement of osteon circularity and population density (also see Garcia-Donas et al, 2020;Streeter, 2012) that are associated with accumulated remodeling activity throughout life (Andronowski & Cole, 2021). Histomorphometric approaches are amenable to statistical quantification of measurement reliability and precision (also see Garcia-Donas et al, 2020;Lagacé et al, 2019) in addition to confidence around associated outputs.…”

“…Recent modifications have been introduced to simplify methods, quantitatively test and improve reliability to quantifying variances relative to remodeling and sampling location, and intra-and interpopulation effects (Crowder et al, 2009;Cummaudo et al, 2018;Dominguez et al, 2020;Garcia-Donas et al, 2020;Lagacé et al, 2019;Milenkovic et al, 2013), and minimizing the invasiveness of bone sampling (e.g., Andronowski et al, 2020;Maat et al, 2006). The most recent research generally follows the same biological rationale identified in the early endeavors, albeit now with improved sensitivity associated with technological improvements, especially micro-CT, high-resolution peripheral quantitative CT, virtual models, and 3D visualization (Hennig et al, 2015;Maggiano et al, 2017;Soltan et al, 2019;and see Andronowski et al, 2018;Andronowski and Cole, 2021; for a comprehensive review of those approaches).…”

The Andronowski Skeletal Collection for Histological Research: A Modern Anatomical Contribution

“…Increas-ing image resolution generally requires decreasing the FOV. A variety of imaging data are currently available for ASCHR and include datasets from brightfield, differential interference contrast (DIC), polarized, and fluorescence microscopy, micro-Computed Tomography (µCT), Synchrotron Radiation micro-Computed Tomography (SRµCT), X-ray Photoelectron Spectroscopy (XPS), and Confocal Laser Scanning Microscopy (CLSM) [10][11][12][13][28][29][30][31][32][33][34][35][36]. The availability of these imaging data allows for many benefits, including (1) opportunities to study ASCHR skeletal samples without having to secure expensive experimental imaging time, (2) providing a permanent record, often in 3D, of the bone collected, thus allowing specimens to be continuously studied nondestructively by researchers, and (3) the careful archiving of data that works to broaden distribution for users accessing the collection.…”

“…Procurement techniques, including sectioning and coring, alter the macromorphology of intact elements but are required to visualize critical components of bone's vascular and cellular networks. Traditional serial sectioning for bone histological analysis, for example, often involves the transverse sectioning of skeletal elements [10,11]. Further, bone procurement protocols for employing Synchrotron Radiation micro-Computed Tomography (SRµCT) experiments require the extraction of bone cores that fit into a determined field of view (FOV) [12,13].…”