Rj. Ordidge et al., ASSESSMENT OF RELATIVE BRAIN IRON CONCENTRATIONS USING T-2-WEIGHTED AND T-2(ASTERISK)-WEIGHTED MRI AT 3-TESLA, Magnetic resonance in medicine, 32(3), 1994, pp. 335-341
In this paper a new method is presented for the relative assessment of
brain iron concentrations based on the evaluation of T-2 and T-2-wei
ghted images. A multiecho sequence is employed for rapid measurement o
f T-2 and T-2, enabling calculation of the line broadening effect (T-
2'). Several groups have failed to show a correlation between T,and br
ain iron content. However, quantification of T-2', and the associated
relaxation rate R(2)', may provide a more specific relative measure of
brain iron concentration. This may find application in the study of b
rain diseases, which cause associated changes in brain iron levels. A
new method of field inhomogeneity correction is presented that allows
the separation of global and local field inhomogeneities, leading to m
ore accurate T-2 measurements and hence, T-2' values. The combination
of T-2, and T-2-weighted MRI methods enables the differentiation of
Parkinson's disease patients from normal age-matched controls based on
differences in iron content within the substantia nigra.