Quantitative computed tomography provides improved accuracy for diagnosis of lumbar osteoporosis in patients with facet joint osteoarthritis: a cross-sectional study.

Abstract

This study employed both QCT and DXA to assess BMD in the same cohort and investigated the influence of FJOA on BMD measurements and the detection rates of osteoporosis. The results indicate that QCT is more accurate for assessing regional BMD in patients with FJOA. This study aimed to compare the detection rates of lumbar osteoporosis in patients with FJOA between QCT and DXA and to analyze the impact of FJOA on regional BMD measurement using each method. This single-center, retrospective, cross-sectional study included participants without a history of spinal instrumentation surgery, spinal fractures of > 2 levels, spinal tumors or infections, and sacralization of lumbar spine. The detection rates of lumbar osteoporosis between QCT and DXA in patients with FJOA were compared using McNemar's test. Associations between BMDs and FJOA severity were assessed using linear mixed models. Discordance in BMD classification between DXA and QCT was categorized as minor or major according to Woodson's definition. The 219 study participants had a mean age of 65.0 ± 10.7 years and included 155 (70.8%) women. The rate of lumbar osteoporosis identification with QCT was noticeably greater than that with DXA (58% vs 34.2%, p < 0.0001). Severe FJOA was independently associated with lower vBMD (multivariable β =  - 4.23 (95% confidence interval (CI), - 7.68 to - 0.77); p = 0.17), while both slight-to-moderate and severe FJOA were independently associated with higher areal BMD (aBMD). With increasing FJOA severity, the aBMD measured by DXA also increased (slight-to-moderate, β = 0.31 (95% CI, 0.16-0.46), p < 0.001; severe FJOA, β = 1.03 (95% CI, 0.79-1.27), p < 0.001). More severe FJOA was associated with higher aBMD on DXA and a lower vBMD on QCT. Additionally, the rate of lumbar osteoporosis detection was significantly higher with QCT than with DXA. These findings indicate that QCT is more accurate for assessing regional BMD in patients with FJOA, supporting the need for caution when using DXA to evaluate BMD in clinical practice.