Correlation between BMD and Radio intensity of Human Bones for Strength Evaluation

Bone mineral density [BMD] generally correlates with bone strength. BMD testing is used to assess bone density and diagnose osteoporosis. The HU scale is a linear transformation of the original linear attenuation coefficient measurement in to one in which the radio-density of distilled water at standard pressure and temperature is defined as Zero Hounsfield Unit while the radio-density of air at STP is defined -1000HU. The correlation between CT numbers and mechanical property estimated from cortical bone were found to be low (r2<0.2) and cancellous bone were found to be higher (r2>0.6). The specific relationship depending on the types of bone, that predict elastic module from density and CT numbers were suggested for human cortical and cancellous bone. CT numbers of HU measures X-ray linear attenuation of tissue inside the voxel.