Jw. Kuiper et al., ACCURACY AND THE INFLUENCE OF MARROW FAT ON QUANTITATIVE CT AND DUAL-ENERGY X-RAY ABSORPTIOMETRY MEASUREMENTS OF THE FEMORAL-NECK IN-VITRO, Osteoporosis international, 6(1), 1996, pp. 25-30
Bone mineral measurements with quantitative computed tomography (QCT)
and dual-energy X-ray absorptiometry (DXA) were compared with chemical
analysis (ChA) to determine (1) the accuracy and (2) the influence of
bone marrow fat. Total bone mass of 19 human femoral necks in vitro w
as determined with QCT and DXA before and after defatting. ChA consist
ed of defatting and decalcification of the femoral neck samples for de
termination of bone mineral mass (BmM) and amount of fat. The mean BmM
was 4.49 g. Mean fat percentage was 37.2% (23.3%-48.5%). QCT, DXA and
ChA before and after defatting were all highly correlated (r>0.96, p<
0.0001). Before defatting the QCT values were on average 0.35 g less t
han BmM and the DXA values were on average 0.65 g less than BmM. After
defatting, all bone mass values increased; QCT values were on average
0.30 g more than BmM and DXA values were 0.29 g less than BmM. It is
concluded that bone mineral measurements of the femoral neck with QCT
and DXA are highly correlated with the chemically determined bone mine
ral mass and that both techniques are influenced by the femoral fat co
ntent.