NMR functional imaging using a tailored RF gradient echo sequence: a true susceptibility measurement technique

Abstract

1992) is applied to functional imaging. The TRFGE technique has the advantage that it is sensitive to the field gradient created by the susceptibility effect, thereby enhancing only the signals from the regions with local field gradient. In addi-tion, the method is insensitive to the in-flow effect, especially from the arterial blood. The latter further simplifies the func-tional MRI data analysis. The TRFGE sequence is, therefore, suitable for functional MR imaging for which true susceptibil-ity effect measurements are of prime importance. To examine the TRFGE functional imaging systematically, experiments with various imaging parameters such as flip angle a, repeti-tion time, and echo time were performed and the results were compared with the data obtained from the conventional gra-dient echo functional MR imaging. The experimental resutts shown were all obtained from human volunteers with a 2.01 whole body MRI system. Key words: functional imaging; tailored RF gradiint echo (TRFGE) technique; true susceptibility measurement; suscep-tibility contrast enhancement in fMRI