Femoral head perfusion and composition: MR imaging and spectroscopic evaluation of patients with systemic lupus erythematosus and at risk for avascular necrosis.

Abstract

To measure fat content and relative marrow perfusion of the femoral head in patients at risk for avascular necrosis. Thirteen patients with systemic lupus erythematosus (SLE) without avascular necrosis and with long-term corticosteroid treatment and 12 healthy subjects were evaluated. Hip perfusion was assessed with gadolinium-enhanced T1-weighted magnetic resonance (MR) imaging. Marrow composition in the femoral head and neck was measured with hydrogen-1 MR spectroscopy. Percentage fat content in the femoral head was similar between the two groups (SLE patients, 77% +/- 5 [standard deviation]; healthy subjects, 78% +/- 6; P = .74). Rate of enhancement of the femoral head was significantly higher in the SLE than the healthy group (11%/min +/- 6 vs 6.9%/min +/- 3, respectively; P = .05), was inversely related to fat content in healthy subjects (r = -.74, P = .02), and was more variable in the SLE group (r = -.53, P = .11). Perfusion of the femoral head is inversely related to marrow fat content in healthy and is higher in SLE patients without hip avascular necrosis.