Science

Bone strength is recognized as a combination of bone mass and bone structural integrity (micro-architecture). Bone mass can be assessed clinically by measurement of bone mineral density using non-invasive radiographic methods. Material properties of bone cannot as yet be determined clinically. Bone turnover can be assessed using a number of biochemical markers. Bone micro-architecture was traditionally only accessible by bone biopsy and can now be determined in a routine clinical setting using high-resolution MRI. For example, certain compounds may increase bone density but actually lead to more fractures. It is clear that to assess fracture risk and drug efficacy, we need to assess overall bone quality, including trabecular micro-architecture.

Below are the structural images of two women who have similar DXA T-scores, yet different bone micro-architecture. This fact highlights that bone mineral density and bone micro-architecture may in fact give treating physicians different answers regarding bone health.

Patient A

Patient B