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

To study whether a dual-layer spectral CT scout scan-based areal BMD estimation method, called Spectral-detector based x-ray absorptiometry (SDXA), can differentiate patients with versus without osteoporotic fractures.

The ability of the method to differentiate patients with osteoporosis was evaluated by assessing the areal BMD at the spine (L1 to L4) in a group of 19 patients presenting at least one fracture and comparing these results to the areal BMD of age- and gender-matched 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.

The average areal BMD of 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%.

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.