Fast 2D and 3D Mapping of T2 Relaxation Time of Cerebral Metabolites

Metabolite T2 relaxation time is necessary for accurate quantification of the absolute concentration of metabolites and may also be an important pathological index. However, lengthy data acquisition time poses a major challenge to mapping metabolite T2. In this project, we aim to obtain fast T2 maps of three major cerebral metabolites: N-acetyl aspartate (NAA), creatine (Cre), and choline (Cho) in clinical acceptable time using a fast spectroscopy imaging technique, called Proton-Echo-Planar-Spectroscopic-Imaging (PEPSI), at 3T MR system. The protocol of less than 30 minutes will be proposed and is expected to improve the applicability in clinical studies. Data acquisition for two-dimensional and three-dimensional metabolite maps with voxel volume of less than 1 ml will be better for regional evaluation especially in the differentiation between the gray and white matter abnormality compared to 8 ml voxel size acquired in single voxel spectroscopy (SVS). Parametric maps of metabolite relaxation times may also be useful as an adjunct to high resolution T2-weighted images to identify brain pathology in patients with neurodegenerative disease and stroke. For the verification we will show that PEPSI spectra at representative regions of interest matched the T2 values obtained using (SVS) and spectral signal-to-noise ratio (SNR) for T2 estimation will be validated by the Pearson’s correlation coefficients between logarithmic MR signals and TEs. In addition, the T2 values of NAA, Cre and Cho, will be compared to those reported in previous studies.

Project ID:PB9712-2080
External Project ID:NSC97-2314-B182-037