Quantitative computed tomography (Q-CT) is a better alternative and should replace dual X-ray absorptiometry (DXA) as the gold standard for detecting spinal osteoporosis. This is according to a recent prospective comparative study, the results of which were published in the journal Spine by Arvind Kulkarni (Bombay Hospital and Medical Research Centre, Mumbai, India) et al.
The study indicated that Q-CT provides a more precise estimation of cancellous bone mineral density than DXA. “With the reliance on DXA for spinal bone mineral density (BMD) estimation being questionable, new standards have to be established for spinal osteoporosis evaluation”, say the researchers. They emphasise that there is “a need for reconsidering osteoporosis evaluation with a site specific and patient specific inclination”.
The study included post-menopausal women that underwent BMD evaluation from January 2018 to December 2020 with either Q-CT or DXA. 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.
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>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 <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%.
Speaking to Spinal News International, Kulkarni said: “We have this huge monumental load of spinal osteoporosis in society, a spin-off of an ageing population, that needs to be addressed at various layers of presentation, either medically, surgically or both.
“In fact, the osteoporotic population that presents to our clinics represent the tip of the iceberg. We keep talking about excellence in clinical practice but still pursue with Dexa scan to detect spinal osteoporosis in spite of knowing that it is a faulty investigation, for reasons highlighted in our research paper.
“It is high time that we put our head on our shoulders and connect the biomechanics of spinal column with osteo-biology and investigate the column (anterior) and its content (trabecular bone) that matter the most.”