Compartmental study of T1 and T2 in rat brain and trigeminal nerve in vivo

The integrated T-1-T-2 characteristics of rat brain and trigeminal nerve water were studied in vivo using a rapid method for acquiring a series of images that depend on T-1 and T-2 relaxation times. Gray matter regions showed only one signal component in both the T-1 and T-2 domains. Trigeminal nerve, however, which has been shown previously to exhibit three T-2 components, was found to also exhibit three T-1 components. The correlations between these T-1 and T-2 components were demonstrated by uniquely filtering out each of the three T-2 components using an inversion-recovery preparation, as determined by the component T-1 values. Based on previous works, it is postulated that each of these three signal components is derived from a unique microanatomical region of the nerve. Knowledge of these T-1 components may thus prove valuable in devising novel methods of identifying the presence and quantifying the volume of tissue subtypes such as myelin. Magn Reson Med 47:274-283, 2002. (C) 2002 Wiley-Liss, Inc.