Non-invasive estimation of age at death has been carried out by using 3D CT scanning of a bog body discovered in 1948 in a peat bog in Borremose (Denmark). The bog body has been dated to the 8th century BC, in the last part of the Bronze Age.
The skeletal structures useful for age estimation have been visualized from CT-scans using the Mimics software from Materialise. Extensive manual editing was necessary, as is common with bog bodies, since the bones were severely degraded and the ordinary range of Hounsfield Units (HU), used for clinical work, is not suitable.
Only the cranium, the left ribs and the right auricular surface were 3D visualized. Based on these visualizations, the age was estimated by applying macroscopic methods routinely used for skeletal remains: the cranial sutures closure (Meindl & Lovejoy 1985), the sternal rib end (Iscan & Loth 1986) and the auricular surface morphology of the ilium (Buckberry & Chamberlain 2002). These three methods resulted in age spans of 27 to 51, 20 to 32 and 25 to 73 years, respectively, as age at death. A recent method specifically adapted for 2D and 3D images (Dedouit et al. 2008) was also applied resulting in an estimated age at death was 16 to 24 years.
Many problems had to be addressed. First of all, the degradation of the skeletal tissue does not allow a complete visualization: the bones are demineralized because of the acidic bog environment. Another problem is the subjectivity that can arise during manual editing, especially where an increased radio-density of connective tissue can mask the real outline of the bones. Finally, the quality of the produced three-dimensional model can be affected by the CT scan slice thickness, with loss of important morphological information.