Bone Density Measurement Using Computed Tomography

Cetin Celenk and Peruze Celenk

ABSTRACT

Ten million Americans have been diagnosed with osteoporosis and 53 million have low bone density, placing them at an increased risk for fragility fractures. As a result, 1 in 4 people will break a bone due to this disease, and the hospitalization burden of osteoporotic fractures is greater than that of heart attacks, stroke, and breast cancer. While effective treatments exist, osteoporosis remains undiagnosed in 80% of patients due to a lack of accurate screening. Bone density measurements via dual-energy X-ray absorptiometry (DEXA) have been accepted as the gold standard to identify patients at risk for osteoporosis and fragility fractures. As a result, DEXA scanners serve a single purpose and are not typically used proactively, leading millions of patients to remain undiagnosed with this silent disease. However, computed tomography (CT) offers the ability to perform bone density measurements opportunistically as part of a routine scan. CT can effectively separate trabecular bone from the cortical shell, allowing for excellent bone density measurements and a more complete use of the information obtained via CT. This course will review the characteristics of osteoporosis, indications for bone density measurement, and the different methods and modalities used to measure bone density, including sonography, DEXA, other variations of X-ray absorptiometry, and the nuances of measuring bone density with quantitative CT (QCT). Measuring bone density with DEXA versus QCT will be compared and contrasted and detailed information and study data will be provided for preparing patients for and performing bone density measurements with QCT.