Fragility fracture risk prediction using quantitative magnetic resonance and Vertebral Bone Quality scoring beyond density

Abstract

Fragility fractures represent a significant global health burden, with osteoporosis affecting over 500 million individuals and contributing to nearly 9 million fractures annually. Conventional diagnosis relies on dual-energy X-ray absorptiometry (DEXA) to measure bone mineral density (BMD), yet BMD alone explains only part of fracture risk. Many fractures occur in patients without osteoporosis by DEXA criteria, underscoring the limitations of bone quantity-based assessment. Advances in imaging and biomarker research highlight the importance of bone quality, microarchitecture, and marrow composition in fracture prediction. Quantitative magnetic resonance imaging (MRI) techniques - including T1ρ, T2 mapping, proton density fat fraction, and diffusion-weighted imaging - offer non-invasive insights into collagen integrity, proteoglycan content, water distribution, and marrow adiposity. These parameters correlate with trabecular deterioration and cortical porosity, enhancing risk stratification beyond BMD. Similarly, Vertebral Bone Quality (VBQ) scoring, derived from routine T1-weighted MRI, provides a practical surrogate for bone quality by quantifying vertebral marrow signal intensity relative to cerebrospinal fluid. Modified VBQ improves accuracy by minimising posterior vertebral artefacts, demonstrating stronger correlation with DEXA T scores and trabecular microarchitecture. Studies show VBQ predicts vertebral fragility fractures independently of BMD, with sensitivity exceeding 90% and discriminatory ability comparable to the fracture risk assessment tool and trabecular bone score. Integration of quantitative MRI and VBQ/modified VBQ into predictive models, supported by artificial intelligence, enables opportunistic, radiation-free screening and more precise fracture risk assessment. Together, these advanced imaging biomarkers represent a paradigm shift toward comprehensive evaluation of bone strength, bridging the gap between bone quantity and quality for improved prevention and management of fragility fractures.

Keywords: Fragility fractures; Bone mineral density; Dual-energy X-ray absorptiometry; T2 mapping; Vertebral Bone Quality score

Core Tip: Fragility fractures remain a global health challenge, with many occurring in patients without dual-energy X-ray absorptiometry-defined osteoporosis. Advanced imaging biomarkers such as quantitative magnetic resonance imaging (T1ρ, T2 mapping, proton density fat fraction, diffusion-weighted imaging) and Vertebral Bone Quality/modified Vertebral Bone Quality scoring provide deeper insights into bone microarchitecture and marrow composition. These tools enhance fracture risk prediction beyond bone mineral density, enabling radiation-free, opportunistic screening and artificial intelligence-driven models that bridge bone quantity and quality for improved prevention and management.