Three-dimensional imaging of past skeletal TB: From lesion to process.

3D imaging has become an essential tool in the field of biological anthropology, notably for human evolution purposes. High resolution virtual 3D reconstructions of original specimens contribute to their preservation and broaden the ability for research, teaching and exchanges. Paleopathology can get substantial benefit from these methods, among others for reconstructing infectious pathological processes on ancient bones. Tuberculosis is frequently diagnosed on ancient human remains; however, some osseous expressions are difficult to interpret using classical methods. We illustrate here the interest of 3D methods for reconstructing processes involved in pathological bone changes due to Mycobacterium tuberculosis infection. Four paleopathological specimens attributed to this infection, dating from different time periods and concerning diverse parts of the skeleton have been analyzed using a specific 3D digital chain we have previously developed. These 3D analyses allow to virtually reconstruct the initial location and aspect of the infectious process, its extension as well as its possible diffusion to the surrounding soft tissues. This possible virtual follow-up of the disease leads to the concept of processual paleopathology that we would like to introduce in the field. The 3D methodology can help to improve our knowledge of natural history and evolution of ancient human infections such as tuberculosis.