MRI method to quantify iron amount in tissues using diffusion magnetic resonance imaging

摘要

A method to quantify and map iron deposits in the brain with diffusion-weighted magnetic resonance imaging (MRI) is based on the differential sensitivity of mono-polar (MPG) gradient pulse diffusion sequences and bipolar (BPG) sequences on the local magnetic field gradients induced by iron deposits and their cross-term with the diffusion-encoding gradients. The method comprises the steps of acquiring (12, 14) first MRI images and second MRI of a Region Of Interest by using MPG and BPG sequences, providing (16) an attenuation model of the diffusion MRI attenuated signal representative of the observed tissue, estimating (18, 20) a first apparent diffusion coefficient ADCMPG and a second apparent diffusion coefficient ADCBPG by fitting the MRI images with the attenuation model, calculating (22) a an iron induced local gradient factor ξ_Fe as (Formula I) (I), and determining (24) the concentration [Fe] and/or the amount of iron stored in the local zone of the tissue from the calculated iron induced local gradient factor ξ_Fe. An apparatus is configured for implementing such a method.