Fw. Wehrli et al., MEASUREMENT OF R-2' IN THE PRESENCE OF MULTIPLE SPECTRAL COMPONENTS USING REFERENCE SPECTRUM DECONVOLUTION, Journal of magnetic resonance [1997], 131(1), 1998, pp. 61-68
Citations number
21
Categorie Soggetti
Physics, Atomic, Molecular & Chemical","Biochemical Research Methods
A method is described for measuring R-2', the RF reversible contributi
on to the effective transverse relaxation rate in yellow trabecular ma
rrow, as a means to evaluate trabecular bone structure and density. Th
e method exploits the similarity in spectral composition of the marrow
and fat in subcutaneous tissue. Under these conditions the gradient e
cho envelope of the marrow signal can be regarded as a convolution of
a function describing the bone marrow intravoxel line broadening (R-2'
) with a function expressing chemical shift modulation, which is obtai
ned from the echo envelope of the subcutaneous fat signal in a referen
ce region. Simple division of each of a series of echoes by the refere
nce signal is shown to afford a smooth decay which can be fitted to a
model to extract R-2'. The method has been evaluated in the upper femu
r of test subjects and a strong correlation of the thus derived R-2' v
alues with those obtained by the GESFIDE technique is demonstrated. Th
e close correspondence in spectral composition of proximal femur marro
w and subcutaneous fat is further illustrated by means of localized sp
ectroscopy. The major potential error source is global inhomogeneity i
n the reference region which can lead to an underestimation of the dem
odulation-derived R-2'. (C) 1998 Academic Press.