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Assessment of relative brain iron concentrations using T 2 ‐weighted and T 2 *‐weighted MRI at 3 Tesla
Author(s) -
Ordidge Roger J.,
Gorell Jay M.,
Deniau Jean C.,
Knight Robert A.,
Helpern Joseph A.
Publication year - 1994
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.1910320309
Subject(s) - t2 relaxation , t2 weighted , nuclear magnetic resonance , substantia nigra , nuclear medicine , iron levels , magnetic resonance imaging , medicine , parkinson's disease , pathology , physics , radiology , disease
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 * ‐weighted images. A multiecho sequence is employed for rapid measurement of T 2 and T 2 *, enabling calculation of the line broadening effect ( T 2 ′). Several groups have failed to show a correlation between T 2 and brain 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 brain 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 more accurate T 2 * measurements and hence, T 2 ′ values. The combination of T 2 *, and T 2 ‐weighted MRI methods enables the differentiation of Parlkinson's disease patients from normal age‐matched controls based on differences in iron content within the substantia nigra.