Quantitative computerized tomography for the diagnosis of osteopenia in prehistoric skeletal remains

In this study, we examine the value of bone density assessed by computed tomography (QCT) of the right tibia in the diagnosis of low bone mass in prehistoric bones. Trabecular bone mass (TBM) was assessed by histomorphometry in undecalcified bone sections of a small part of the proximal epiphysis of the right tibia of 78 prehispanic individuals. Bone density was also assessed in the proximal epiphysis of the right tibia, in an area of cancellous bone immediately adjacent to the wedge which was destined to histomorphometry, with the aid of a Tomoscan 60 TX™ (Philipps Medical System, Eindhoven, The Netherlands) using a phantom of hydroxyapatite included in plastic resin at three known concentrations (50, 100 and 200 mg/cc) and ethanol as fat equivalent. Bone density (as bone hydroxyapatite concentration in milligram per cubic centimeter) was calculated by means of a specific software tool (QCT Bone Mineral Analysis System, Image Analysis, California). We compared bone density assessed with QCT with TBM in these individuals, and also, with the results obtained from a modern control group. We calculated the median TBM of the prehispanic sample and tested the sensitivity, specificity, and overall accuracy of QCT in diagnosing TBM values below the median. We later performed the same analyses on 24 more prehispanic individuals. Both QCT (t = 5.61, p < 0.001) and TBM (t = 3.79, p < 0.001) were significantly lower among the prehispanic individuals than among the control ones. QCT showed a significant relationship with TBM (r = 0.41, p < 0.001). QCT values below 100 mg/cc serve to establish a diagnosis of low TBM values with a sensitivity of 82.1% and a specificity of 41%. In the test group sensitivity was 83.3% and specificity, 50%.