MRI signal intensity per vertebral volume: a novel biomarker in pediatric osteoporosis.

This study aimed to evaluate the diagnostic performance of a novel MRI-based parameter—MRI signal intensity per unit vertebral volume—in identifying low bone mineral density (BMD) in children and adolescents, alongside established MRI metrics including mean L1-L4 signal intensity and vertebral bone quality (VBQ) score. The study included 106 osteoporotic patients (aged 5–18 years) who had not yet reached 18 years of age, and 46 age-matched controls. Subjects were grouped into childhood (5–11 years) and adolescence (> 12 years). Using 1.5 T MRI, mean L1-L4 signal intensity, VBQ score, and signal intensity per unit volume were calculated. MRI findings were compared using t-tests and ANOVA; diagnostic accuracy was assessed via ROC curve analysis. In the childhood group, all MRI parameters significantly differed between low bone mineral density and control subjects (p < 0.05). In adolescents, only mean signal intensity and signal intensity per unit volume were significant. The new parameter demonstrated the highest diagnostic value, with AUCs of 0.792 and 0.836 in childhood and adolescence groups, respectively. MRI signal intensity per unit vertebral volume showed superior performance in detecting low BMD compared to existing MRI-based indices. This parameter offers a radiation-free, size-adjusted alternative to DXA, particularly valuable in pediatric patients requiring long-term monitoring.