Prediction of bone loss in elderly female subjects by MR perfusion imaging and spectroscopy

To determine whether MR perfusion indices or marrow fat content at baseline can predict areal bone mineral density (BMDa) loss. Repeat dual x-ray absorptiometry (DXA) of the hip was performed in female subjects at 2 years (n = 52) and 4 years (n = 45) following baseline MR perfusion imaging and spectroscopy of the hip. Percentage reduction in femoral neck BMDa at 4 years post-baseline was greater in subjects with below median acetabulum enhancement slope (E-slope) (-5.6 +/- 1.2 Vs -1.1 +/- 1.2 (mean +/- standard error) p = 0.014) or muscle maximum enhancement (E-max) (-5.7 +/- 1.2 Vs -0.23 +/- 1.2, p = 0.009) after adjusting for baseline co-variables. Baseline MR parameters correlated with reduction in BMDa at 4 years (acetabulum E-slope r = 0.517, p = 0.0003; muscle E-max r = 0.306, p = 0.043) as well as traditionally applied clinical risk factors. Acetabulum E-slope, femoral neck E-max and marrow fat content at baseline had sensitivities of 89%, 81% and 72% respectively at distinguishing between fast (> 1%/annum) (n = 18) and slow (< 1%/annum) (n = 27) BMD losers. Elderly female subjects with reduced perfusion indices at baseline had increased femoral neck bone loss at 4 years. Selected perfusion indices and marrow fat content have a moderate to high sensitivity in discriminating between fast and slow bone losers.