February 14, 2013

Speaker: Sofia Chavez, Centre for Addiction and Mental Health (CAMH)

Title: Overcoming the Challenges of Quantitative MRI: An Accurate and Fast T1 Mapping Method

Abstract: MRI can produce anatomical images with exquisite contrast, where the signal is a relative measure of intensity that is governed by MR sequence parameters (we control) and intrinsic tissue parameters. Quantitative MRI aims to extract the intrinsic tissue parameters from the image signal in a reasonable amount of scan time. However, the ability to accurately quantify an MR parameter is dependent on how accurately we can model the MR signal and how well we can measure the various factors included in the models. Most factors are subject dependent and thus require measurement on a per subject basis, resulting in lengthy, impractical scan times. In this talk I will review some of the most important MR parameters (T1, T2, proton density) that govern the signal contrast as well as discuss some magnetic field related inaccuracies that plague most quantitative measurements: B1 field inhomogeneities and slice profiles. I will illustrate the process of developing new quantitative MRI techniques by describing a new, accurate and fast T1 mapping method. I will also present current applications of this technique in the study of addiction and psychiatric disorders at CAMH.