MRI Relaxation of Brain Tissue: A Statistical Estimate of Deviations from Ideality

Abstract

Although the determination of tissue relaxation parameters from MRI intensities is straightforward in principle, a number of factors may render conventional analysis difficult in practice. Many of these nonideal factors have been studied theoretically and experimentally: effects of static and RF field in-homogeneities and RF phase imperfections on T2 measurements in pulse NMR experiments (Void et al. 1973), RF and static field inhomogeneity effects on T2 measurements derived from MRI multiecho images (Majumdar et al. 1986a, b), effects of selective pulses on T1 measurements (Joseph et al. 1984), analysis of multiexponential magnetization decay (Sandor et al. 1988), and “cross-talk” effects on T1 and T2 measurements in slice-selective MRI imaging experiments (Just et al. 1988).