Guest Blog #4: A Non-Destructive Technology for Palaeopathology: Differential Diagnosis of Cranial Lesions in Archaeological Human Populations

Jennifer Morgan is a PhD candidate in the Department of Anthropology at Western University.  Jennifer has been working with Sustainable Archaeology's microCT scanner to scan and analyze Maya and Egyptian archaeological cranial samples exhibiting cribra orbitalia and/or porotic hyperostosis in order to assess whether the microCT is a more effective tool than destructive thin section techniques to study the etiology, activity, and healing of the lesions. 

This blog features Jennifer's contribution to the upcoming edition of the Sustainable Archaeology newsletter, Notes from the SA, which will be published on February 7th.

A Non-Destructive Technology for Palaeopathology: Differential Diagnosis of Cranial Lesions in Archaeological Human Populations

Jennifer Morgan, PhD Candidate, Western University 

Palaeopathology is defined as the scientific study of disease processes from archaeological human remains. The pattern of disease that affects a population is the expression of the biological and cultural stressors to which they were exposed. It is influenced by the environment, sex, social status, diet, occupation, and even cultural belief systems. These factors help researchers to interpret and explain the patterns of disease observable on human skeletal remains. Recent microscopic analyses of bone have revealed that porotic lesions of the skull, referred to as cribra orbitalia and porotic hyperostosis, can be caused by more than one health related condition. Originally associated with anaemia, other conditions including vitamin deficiencies and localized infections have also been implicated as possible causes of these lesions. Therefore, it is critical to establish methods that can accurately assess health conditions from skeletal remains. Inaccurate diagnoses can have significant implications for our current understandings of how disease and other health related conditions may have evolved over time, across geographic space, and how they may have affected human populations in the past.

The purpose of my current doctoral research is to examine an innovative non-destructive method for improving the accuracy of disease diagnosis in archaeological skeletal samples.  The principal objective of this study is to determine whether micro-computed tomography (μCT) and advanced methods of digital image analysis can be used in palaeopathology to visualize small scale bone changes which are typical of certain health conditions. The goals of this research are two-fold.  First, I wish to assess the capability of μCT and digital image analysis as sufficient alternatives to destructive thin section techniques which are traditionally used for microscopic skeletal analysis in bioarchaeological research. Second, I wish to evaluate the ability of µCT for more reliable differentiation between the various pathological conditions that contribute to the presence skeletal lesions in archaeological human remains.

Why is this significant?  In order to establish a reliable diagnosis it is often necessary to analyze the microscopic structures of diseased bone. Microscopy is essential in palaeopathology since although several disease processes can lead to similar bone surface changes, microscopic analyses demonstrate that there are patterns of microscopic changes which are unique to specific diseases. The classic way to examine bone microscopically is through the use of histological thin sections of bone, which require significant preparation and destruction of the sample. The method proposed for my doctoral research, using μCT, requires little to no sample preparation and is a method which has the potential for high resolution bone analysis, while eliminating the need for destructive sampling of valuable archaeological remains. 

For this research project, skeletal samples have been drawn from an Egyptian and several Maya collections housed at Western University in London, Ontario.  A large number of individuals with observable porotic cranial lesions have been μCT scanned in the Ancient Images Laboratory.  The resulting images are currently being qualitatively and quantitatively analyzed using the digital image analysis software VGStudio Max 2.2. These analyses of bone structural changes will determine whether the characteristic microscopic patterns indicative of anaemia, vitamin deficiencies, and infectious processes described in the literature can be differentiated using μCT. It is anticipated that the results of this research project will make a significant contribution to palaeopathology by providing non-destructive, high resolution digital techniques for the diagnosis of disease from archaeological skeletal samples as well as vastly improving our epidemiological understandings of health and disease in archaeological populations.