MRI‑based vertebral bone quality score is a comprehensive index reflecting the quality of bone and paravertebral muscle

BACKGROUND Recently, vertebral bone quality (VBQ) score has been shown to predict bone mineral density (BMD) and spine-related postoperative complications. However, in clinical work, we found that patients with higher VBQ scores also had more severe paravertebral muscle degeneration. PURPOSE To explore the ability of the VBQ score to evaluate BMD and paravertebral muscle quality. STUDY DESIGN/SETTING Retrospective single-center cohort. PATIENT SAMPLE Patients in the spinal surgery department of our hospital. OUTCOME MEASURES BMD and T-score were measured by dual-energy X-ray absorptiometry (DXA). The Picture Archiving and Communication Systems (PACS) measured the cross-sectional area (CSA) of the paravertebral muscles. Image J software was used to measure the degree of fat infiltration (DFF) of the paraspinal muscle. METHODS Patients who underwent lumbar MRI and DXA simultaneously within two weeks were enrolled. The VBQ score was calculated using T1-weighted lumbar MRI images. Firstly, BMD-related and muscle-related parameters of patients with different VBQ scores were compared. Then, the correlation coefficients between the VBQ score and the parameters of BMD and paravertebral muscle were calculated. Finally, multivariate linear analysis was used to compare the contribution of each variable to the VBQ score. RESULTS A total of 101 patients were eventually included in this study for analysis. When the VBQ score was greater than 3.0, the patients were mostly female, older, less likely to smoke, and had lower BMD. Interestingly, we found that patients with VBQ scores greater than 3.0 had smaller CSA of the paravertebral muscles (ES: 17.53±3.36 vs. 19.13±3.97, p=0.032; total: 29.59±5.27 vs. 34.12±7.02, p<0.001) and higher DFF (MF: 22.47±5.93 vs. 19.64±5.28, p=0.015; ES: 17.71±4.67 vs. 15.74±4.62, p=0.038; PM: 13.70±3.32 vs. 11.33±3.02, p<0.001; average: 17.96±3.78 vs. 15.57±3.42, p=0.001). The VBQ score was negatively correlated with the CSA (MF: r =-0.316, p=0.001; ES: r =-0.388, p=0.001; PM: r =0.388, p=0.001) and positively correlated with the DFF (MF: r =0.344, p<0.001; ES: r =0.439, p<0.001; PM: =0.416, p<0.001). In multivariate linear analysis, BMD, total CSA, and average DFF determined the value of the VBQ score, and the contribution of paravertebral muscle was higher than that of BMD (BMD: r =-0.203, p=0.024; total CSA: r=-0.294, p=0.003; average DFF: r =0.261, p=0.011). CONCLUSIONS This study is the first to find a positive association between the VBQ score and paravertebral muscle degeneration, and this association may be independent of BMD. VBQ can reflect the quality of bone and paravertebral muscle, which is its special advantage in clinical application.