Magnetic resonance measures of trabecular and cortical bone architecture alterations in corticosteroid treated boys with Duchenne muscular dystrophy

Topic:

Translational Research

Poster Number: S68

Author(s):

Remya Kunnath Ravindranunni, PT, University of Florida, Rasleen Grewal, BS, University of Pennsylvania, Christiana Cottrell, BA, University of Pennsylvania, Angelina Bernier, MD, University of Florida, Ibrahim Tuna, MD, University of Florida, Krista Vandenborne, PT, PhD, University of Florida, Glenn Walter, PhD, University of FL Department of Physiology and Aging, Chamith Rajapakse, PhD, University of Pennsylvania, Rebecca J. Willcocks, PhD, University of Florida

Background: In Duchenne muscular dystrophy (DMD), bone microarchitecture changes due to osteoporosis result in long-bone and vertebral fractures (VFs) leading to increased morbidity and mortality. Prolonged corticosteroid usage, delayed puberty, and decreased muscle loading result in poor bone health. While DXA- BMD is the most common imaging method for bone in DMD, MRI can be used to non-invasively measure cortical and trabecular architecture of bone and may detect its alterations in DMD.
Methods: 32 participants were grouped in to DMD (n=18, age: mean± SD=12.6 ± 3.2 years; corticosteroid exposure duration = 7.8 ± 3.4y) and unaffected control (n=14, age=14.6 ± 3.8y) groups in this cross-sectional study. A 3T whole body MRI scanner (Siemens Prisma) was used to obtain high resolution gradient echo images of the distal femur, which were then analyzed to extract trabecular and cortical bone characteristics.
Results: MR measured bone stiffness, cortical bone thickness (Cb.Th), trabecular thickness (Tb.Th), and bone volume fraction (BV/TV) are significantly less in DMD than controls (p< 0.004 for all). Bone stiffness is negatively correlated with age in DMD, but not in controls (DMD: R2= 0.568, P= 0.003; Control: R2= 0.450, P= 0.47), Cb.Th significantly decreases with age in DMD but not control subjects (DMD: R2= 0.393, P= 0.005; Control: R2= 0.450, P= 0.47). Tb.Th increases significantly with age in controls, but not in DMD (DMD: R2= 0.144, P= 0.121; Control: R2= 0.287, P= 0.048). BV/TV significantly decreases with age in DMD, not in controls (DMD: R2= 0.53, P= 0.0006; Control: R2= 0.07, P= 0.36). Bone stiffness and BV/TV in DMD significantly decrease with corticosteroid exposure duration (Stiffness: R2= 0.26, P= 0.03; BV/TV: R2= 0.25, P= 0.03). Conclusion: MR measures of cortical and trabecular bone architecture are significantly altered in boys with DMD and are associated with age and duration of corticosteroid use. Funding Sources: This study is funded by the US Department of Defense (W81XWH-21-1-0566, PI: Willcocks).