Relationship of magnetic resonance measures of bone quality with bone mineral density in corticosteroid treated boys with Duchenne muscular dystrophy

Topic:

Translational Research

Poster Number: P155

Author(s):

Remya Kunnath Ravindranunni, PT, PhD candidate, University of Florida, Kevin Cho, University of Pennsylvania, Alyssa Rosen, University of Pennsylvania, Sri Drishaal Kumar, University of Pennsylvania, Mahdi Mustafa Hurreh, University of Pennsylvania, Angelina V Bernier, MD, University of Florida, Ibrahim Tuna, MD, University of Florida, Krista Vandenborne, PhD, University of Florida, Glenn A Walter, PhD, University of Florida, Chamith S Rajapakse, MD, PhD, University of Pennsylvania, Rebecca J Willcocks, PhD, University of Florida

Background: In Duchenne muscular dystrophy (DMD), osteoporosis due to corticosteroid use, altered muscle-bone crosstalk, and decreased bone loading results in fractures, leading to increased morbidity and mortality. In adult osteoporosis, bone mineral density measured using dual-energy X-ray absorptiometry (DXA-BMD) is the gold standard for bone health assessment, it is an insufficient predictor of fracture risk in DMD. Magnetic resonance (MR) imaging can assess bone quality through bone marrow fat fraction (BMFF) and cortical/trabecular microstructure. These measures are correlated with age and corticosteroid use in DMD. This study investigates the relationship between these MR-based bone quality metrics and BMD in corticosteroid-treated boys with DMD.
Methods: This cross-sectional study included 15 boys with DMD (mean age: 12.7 ± 3.2 years; corticosteroid exposure duration: 8.0 ± 3.2 years). DXA-BMD was taken from clinical scan reports provided by participants. MR imaging was performed using a 3T MRI scanner (Siemens Prisma/Philips Achieva) to measure BMFF at the L4 vertebral body and distal femur and trabecular & cortical bone architecture at the distal femur.
Results: Spine BMFF showed a significant negative correlation with DXA axial z-scores of BMD (P=0.02, R²=0.4354). Positive correlations were observed between DXA total body less head (TBLH) z-scores and MR-derived bone stiffness (P=0.003, R²=0.5791), bone volume fraction (P=0.04, R²=0.3293), and surface-to-curve ratio (P=0.0028, R²=0.5715). Negative correlations were found for erosion index (P=0.002, R²=0.6009), total bone area (P=0.01, R²=0.4331), and trabecular area (P=0.0013, R²=0.6267). Distal femur FF exhibited a trend towards negative correlation with TBLH z-scores (P=0.09, R²=0.2615), while trabecular thickness showed a positive trend (P=0.08, R²=0.2528). Cortical bone dimensions did not correlate with TBLH z-scores.
Conclusion: MR measures of bone quality are significantly associated with DXA-BMD in boys with DMD. MRI may offer additional information on specific bone characteristics that are negatively affected by DMD and corticosteroid use.