Inter-Vertebral Signal Concordance Index is a Risk Factor for Osteoporotic Vertebral Compressed Fracture: Validated by Finite Element Analysis

Study DesignRetrospective study.ObjectiveWe found that inter-vertebral signal concordance index (ISCI), as a novel factor, was significantly higher in the osteoporotic vertebral compressed fracture (OVCF) patients than non-OVCF patients in our previous retrospective study. In this study, we aim to validate the association between ISCI and OVCF using finite element analysis (FEA).MethodsFrom the non-fracture cohort of our previous diagnostic study, 18 female patients (50-75 years) with degenerative lumbar disease were selected. To minimize confounding factors affecting bone strength, paired patients were matched under criteria: 1. The same femoral neck T-score; 2. Age caliper of 4 years. FEA was adopted to predict vertebral bone strength under 500N compression and failure load for the paired patients.ResultsAmong three ISCI subtypes (T1, T2, STIR), only STIR-ISCI showed significant biomechanical differences: Compared to lower STIR-ISCI group, the higher STIR-ISCI group exhibited increased vertebral deformation (2.62 ± 0.72 mm vs 1.24 ± 0.55 mm, <i>P</i> = .002) and increased stress distribution (10.92 ± 1.98 MP vs 6.49 ± 2.87 MP, <i>P</i> = .002) under 500N load. Moreover, the yield strength in the higher STIR-ISCI group was lower (4443.11 ± 8.99 N vs 4467.67 ± 9.66, <i>P</i> < .001). Consequently, the deformation at yield strength was higher in the higher STIR-ISCI group (21.25 ± 4.73 mm vs 15.55 ± 2.55 mm, <i>P</i> = .027). No differences were observed in the T1-ISCI or T2-ISCI subgroups.ConclusionsSTIR-ISCI is an independent risk factor for OVCF, strongly associated with compromised vertebral biomechanics independent of bone mineral density. This magnetic resonance imaging-derived biomarker offers a promising tool for clinical fracture risk stratification.