Myth 2: DXA is the original Gold Standard

Originally developed in the early 80’s, QCT has several advantages over Dual-energy X-ray Absorptiometry (DXA) for the measurement of BMD  in patients with degenerative disease and arthritis but was superseded by DXA early on, primarily due to the high cost and limited availability of early CT scanners. In addition, these early CT scanners where slow and so a QCT bone density test might take 30 minutes or so which made the exam expensive. During the 1990’s DXA became the most prevalent method of bone density testing and is now recommended as the “gold standard” method despite some well recognized deficiencies in this approach. Importantly, the proportion of fractures attributable to osteoporosis based on a standard definition of using a DXA BMD T-score of less than −2.5 is very modest, ranging from less than 10% to 44%.