SUSCEPTIBILITY EFFECT-ENHANCED FUNCTIONAL MR-IMAGING USING TAILORED RF GRADIENT-ECHO (TRFGE) SEQUENCE

Abstract

In this article, we have described a tailored radio frequency gradient echo (TRFGE) technique which is applied to functional imaging. The TRFGE technique is insensitive to the inflow effect, which often complicates the analysis of functional magnetic resonance imaging (FMRI) data, and is also insensitive to nonfunctional backgrounds such as static tissues. The susceptibility effect measurement obtained from the TRFGE technique therefore provides a unique form of functional imaging, namely, susceptibility-only functional imaging. To examine TRFGE functional imaging systematically, we designed an experiment to determine the flow effect and susceptibility-dependent signal change by varying the imaging parameters including flip angle alpha, repetition time TR, and echo time TE. The results obtained were then compared with the data obtained with conventional gradient-echo (CGE) functional MR imaging. The experimental results shown were all obtained using human volunteers with a 2.0-T whole-body MRI system. (C) 1995 John Wiley & Sons, Inc.