Spectral-detector based x-ray absorptiometry (SDXA): In-vivo bone mineral density measurements in patients with and without osteoporotic fractures

Objectives: To study whether a dual-layer spectral CTscout scan-based arealBMDestimation method, called Spectral-detector based x-ray absorptiometry (SDXA), can differentiate patients with versus without osteoporotic fractures. Methods: The ability of the method to differentiate patients with osteoporosis was evaluated by assessing the arealBMDat the spine (L1 to L4) in a group of 19 patients presenting at least one fracture and comparing these results to the arealBMDof age- and gendermatched controls (57 patients). Finally, the reproducibility of SDXA was evaluated in-vivo through the calculation of coefficients of variation (CV), using three repeated analyses performed on each patient. Results: The average arealBMDof patients presenting fractures, measured with the scout scan-based method (0.86±0.17 g cm-2), was found to be significantly lower than the average BMD of the control group (1.00±0.17 g cm-2, p=0.043). The reproducibility of the method in-vivo was found to be reasonable, with CVs ranging between 3.1 and 6.9%. Conclusions: The results illustrate that the SDXA method for DXA-equivalent areal BMD estimation -delivers the ability to distinguish patients presenting osteoporotic fractures. Considering the total number of CT examinations worldwide, SDXA could develop to be a useful tool for truly opportunistic osteoporosis screening for a future clinical day-to-day routine.