Fatty Acid Composition of Proximal Femur Bone Marrow Adipose Tissue in Subjects With Systemic Lupus Erythematous Using 3 T Magnetic Resonance Spectroscopy.

ABSTRACT

BACKGROUND: Systemic lupus erythematosus (SLE) is a chronic, inflammatory disease with common musculoskeletal manifestations, notably reductions in bone quality. Bone marrow adipose tissue composition and quantity has been previously linked to bone quality and may play a role in SLE pathophysiology but has not been thoroughly studied. PURPOSE: To use magnetic resonance spectroscopy (MRS) to investigate bone marrow adipose tissue quantity and composition in proximal femur subregions of untreated SLE patients compared to controls and treated patients. STUDY TYPE Prospective. SUBJECTS: A total of 64 female subjects: 28 SLE, 15 glucocorticoid (GC)-treated SLE and 21 matched controls. FIELD STRENGTH/SEQUENCE Stimulated echo acquisition mode (STEAM) sequence at 3 T. ASSESSMENT MRS was performed at multiple echo times in the femoral neck and trochanter regions and fatty acids (FA) composition was computed. STATISTICAL TESTS Intergroup comparisons were carried out using ANOVA. A P value < 0.05 was considered statistically significant. RESULTS: SLE patients had significantly higher saturated FA compared to controls in both the femoral neck (+0.12) and trochanter (+0.11), significantly lower monounsaturated FA in the trochanter compared to controls (-0.05), and significantly lower polyunsaturated FA in the femoral neck compared to both controls (-0.07) and SLE patients on GC therapy (-0.05). DATA CONCLUSION: SLE patients have altered proximal femur marrow fat metabolism, which may reflect a manifestation of, or play a role in, the altered inflammatory response of these patients. EVIDENCE LEVEL 2 TECHNICAL EFFICACY Stage 2.