Evaluating the role of quantitative dual lumbar vertebral radioactive counts ratio using 99m-technetium-labeled methylene diphosphonate single-photon emission computed tomography/computed tomography in the assessment of osteoporosis

OBJECTIVE: To evaluate the utility of 99m-technetium-labeled methylene diphosphonate single-photon emission computed tomography/computed tomography (SPECT/CT) in the quantitative analysis of the dual lumbar spine to assess osteoporosis. METHODS: A retrospective analysis was conducted on 60 patients who underwent SPECT/CT bone imaging between January 2018 and April 2025. Based on dual-energy X-ray absorptiometry measurements of lumbar spine and femoral T-scores, participants were divided into osteoporotic (n = 31) and non-osteoporotic (n = 29) groups. The mean radioactive counts ratio (T/NTmean) of the two normal lumbar vertebrae to the erector spinae at the L3 level were measured. Correlations of lower T-score, age, height, weight, BMI, and lower bone mineral density (BMD) with the T/NTmean were explored using Pearson correlation analyses. Diagnostic value of the T/NTmean for osteoporosis was assessed by receiver operating characteristic (ROC) curve analysis. RESULTS: Weight, BMI, lower T-score, and lower BMD were positively correlated with T/NTmean for different bilumbar spine combinations (r: 0.417-0.701, all P < 0.01). Age was negatively correlated (r: 0.595 to -0.409, all P < 0.05); height showed no correlation (all P > 0.05). ROC curve analysis revealed that the T/NTmean had diagnostic efficacy for osteoporosis, with an area under the curve of 0.845, a sensitivity of 85.2%, and a specificity of 72.8%. CONCLUSION: Quantitative evaluation of the dual lumbar spine using SPECT/CT effectively reflects the BMD of patients, which can provide a viable basis for screening for opportunistic osteoporosis in some patients with lumbar spine lesions.