Should Q-CT Be the Gold Standard for Detecting Spinal Osteoporosis?

Study Design. Prospective comparative study. Objective. Refinement of the guidelines for screening of osteoporosis and considering quantitative computed tomography (Q-CT) for detecting spinal osteoporosis. Summary of Background Data. Spinal osteoporosis is often underestimated and under-evaluated due to either lack of availability of the diagnostic modality or lack of awareness about the possibility of overestimation by dual X-ray absorptiometry (DXA) scan. There is a need for reconsidering osteoporosis evaluation with a site specific and patient specific inclination. Methods. Post-menopausal women that underwent bone mineral density (BMD) evaluation from January-2018 to December-2020 with either Q-CT or DXA were evaluated. Comparison studies of the distribution of age and T-scores of the bone densities obtained from the two study groups: age-matched, sex-matched, and common skeletal site of interest (L1-4 vertebrae) were performed. Mann–Whitney U test, correlation and regression analyses were performed and bell curves were plotted. Results. Of the 718 women evaluated, 447 underwent Q-CT and 271 underwent DXA. There was no significant difference among the age distribution of the two study groups ( P -value > 0.05). The mean and mode T-scores obtained by Q-CT and DXA were found to be –2.71, –3.8 and –1.63, –1.7 respectively. A highly significant difference in the T-scores was observed in the Q-CT and DXA groups ( P -value < 0.0001). Among those who were screened by Q-CT, 58.16% were osteoporotic, 37.58% were osteopenic, and 4.25% were normal. The respective percentages in the DXA group were 30.63%, 49.82%, and 19.55%. Conclusion. Q-CT provides more precise estimation of cancellous bone mineral density than DXA. With the reliance on DXA for spinal BMD estimation being questionable, new standards have to be established for spinal osteoporosis evaluation. Q-CT can be a better alternative to replace DXA as the gold standard for the evaluation of spinal osteoporosis. Level of Evidence: 2