Exploring Fat Fraction and Vertebral Bone Quality Score in Lumbar Spine Magnetic Resonance Imaging: A Cross-Sectional...

Background/Objectives: While gradient-echo (GRE)-based chemical shift-encoded magnetic resonance imaging (CSE-MRI) offers precise method for measuring adiposity in bone marrow, its limitation lies in the need for additional imaging. On the other hand, spin-echo (SE)-based CSE-MRI can seamlessly integrate into conventional protocols. Recently, a novel technique called the vertebral bone quality (VBQ) score has been introduced. The objective of this study was to investigate the association between fat fraction (FF) measured by GRE-based CSE-MRI (FF_GRE) and FF measured by SE-based CSE-MRI (FF_SE) or the VBQ score. Methods: A retrospective study with 344 patients assessed the correlation between FF and the VBQ score and each measurement's correlation with age using Pearson's correlation (r). Concordance between FF_GRE and FF_SE was assessed using Lin's concordance correlation coefficient (ρ_c). Vertebral lesions (n = 41) were categorized as benign and malignant, and the Mann-Whitney U test was used for comparison. Results: FF_GRE demonstrated strong positive correlations with FF_SE and the VBQ score (r = 0.861 and 0.708, respectively). However, the concordance between FF_GRE and FF_SE was poor (ρ_c = 0.295). All measurements moderately correlated with age (FF_GRE, r = 0.583; FF_SE, r = 0.477; VBQ score, r = 0.468). FF was significantly higher in benign lesions (FF_GRE, p = 0.004; FF_SE, p = 0.007), while the VBQ score did not show statistically significant differences between the two groups (p = 0.089). Conclusions: FF_GRE exhibited a high correlation with the VBQ score. FF_SE showed a strong correlation with FF_GRE, but replacing FF_GRE with FF_SE may be challenging. Both FF and the VBQ score moderately correlated with age. FF demonstrated statistically significant differences between benign and malignant lesions, while the VBQ score did not provide a distinguishable separation.