Assessment of relative brain iron concentrations using T2-weighted and T2*-weighted MRI at 3 Tesla

✍ Scribed by Roger J. Ordidge; Jay M. Gorell; Jean C. Deniau; Robert A. Knight; Joseph A. Helpern

• Publisher: John Wiley and Sons
• Year: 1994
• Tongue: English
• Weight: 794 KB
• Volume: 32
• Category: Article
• ISSN: 0740-3194
• DOI: 10.1002/mrm.1910320309

✦ Synopsis

Abstract

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.