Marrow Fat-Cortical Bone Relationship in β-Thalassemia: A Study Using MRI

Background: Growing evidence suggests that marrow adipocytes play an active role in the regulation of bone metabolism and hematopoiesis. However, research on the relationship between bone and fat in the context of hematological diseases, particularly beta-thalassemia, remains limited. Purpose: To investigate the relationship between marrow fat and cortical bone thickness in beta-thalassemia and to identify key determinants influencing these variables. Study TypeProspective. Subjects: Thirty-five subjects in four subject groups of increasing disease severity: 6 healthy control (25.0 +/- 5.3 years, 2 male), 4 beta-thalassemia minor, 13 intermedia, and 12 major (29.1 +/- 6.4 years, 15 male). Field Strength/Sequence 3.0 T, 3D fast low angle shot sequence and T1-weighted turbo spin echo. Assessment Analyses on proton density fat fraction (PDFF) and R2* values in femur subregions (femoral head, greater trochanter, intertrochanteric, diaphysis, distal) and cortical thickness (CBI) of the subjects' left femur. Clinical data such as age, sex, body mass index (BMI), and disease severity were also included. Statistical Tests One-way analysis of variance (ANOVA), mixed ANOVA, Pearson correlation and multiple regression. P-values <0.05 were considered significant. Results Bone marrow PDFF significantly varied between the femur subregions, F(2.89,89.63) = 44.185 and disease severity, F(1,3) = 12.357. A significant interaction between subject groups and femur subregions on bone marrow PDFF was observed, F(8.67,89.63) = 3.723. Notably, a moderate positive correlation was observed between PDFF and CBI (r = 0.33-0.45). Multiple regression models for both PDFF (R2 = 0.476, F(13,151) = 10.547) and CBI (R2 = 0.477, F(13,151) = 10.580) were significant. Significant predictors for PDFF were disease severity (beta TMi = 0.36, beta TMa = 0.17), CBI (beta = 0.24), R2* (beta = -0.32), and height (beta = -0.29) while for CBI, the significant determinants were sex (beta = -0.27), BMI (beta = 0.55), disease severity (beta TMi = 2.15), and PDFF (beta = 0.25). Data Conclusion This study revealed a positive correlation between bone marrow fat fraction and cortical bone thickness in beta-thalassemia with varying disease severity, potentially indicating a complex interplay between bone health and marrow composition. Evidence Level 2 Technical Efficacy Stage 3