Use of MRI-based vertebral bone quality score (VBQ) of S1 body in bone mineral density assessment for patients with lumbar degenerative diseases

Purpose To evaluate the use of the modified and simplified vertebral bone quality (VBQ) method based on T1-weighted MRI images of S1 vertebrae in assessing bone mineral density (BMD) for patients with lumbar degenerative diseases. Methods We reviewed the preoperative data of patients with lumbar degenerative diseases undergoing lumbar spine surgery between January 2019 and June 2022 with available non-contrast T1-weighted magnetic resonance imaging (MRI), computed tomography (CT) images and dual-energy X-ray absorptiometry (DEXA). S1 vertebral bone quality scores (S1 VBQ) and S1 CT Hounsfield units were measured with picture archiving and communication system (PACS). One-way ANOVA was applied to present the discrepancy between the S1 VBQ of patients with normal bone density (T-score ≥ − 1.0), osteopenia (− 2.5 < T-score < − 1.0) and osteoporosis (T-score ≤ − 2.5). The receiver operating characteristic curve (ROC) was drawn to analyze the diagnostic performance of S1 VBQ in distinguishing low BMD. Statistical significance was set at p < 0.05. Results A total of 207 patients were included. The S1 VBQ were significantly different between groups ( p < 0.001). Interclass correlation coefficient for inter-rater reliability was 0.86 (95% CI 0.78–0.94) and 0.94(95% CI 0.89–0.98) for intra-rater reliability. According to the linear regression analysis, the S1 VBQ has moderate-to-strong correlations with DEXA T-score ( r = − 0.48, p < 0.001). The area under the ROC curve indicated a predictive accuracy of 82%. A sensitivity of 77.25% with a specificity of 70% could be achieved for distinguishing low BMD by setting the S1 VBQ cutoff as 2.93. Conclusions The S1 VBQ was a promising tool in distinguishing poor bone quality in patients with lumbar degenerative diseases, especially in cases where the previously reported VBQ method based on L1–L4 was not available. S1 VBQ score could be useful as opportunistic assessment for screening and complementary evaluation to DEXA T-score before surgery.