Functional magnetic resonance imaging using non-Fourier, spatially selective radiofrequency encoding.
A new method for functional magnetic resonance imaging (fMRI) employing non-Fourier encoding using spatially selective radiofrequency (RF) excitation is presented. The method uses manipulation of spatially selective RF pulses to encode spins in the slice-select direction. The method has several advantages over standard multislice approaches. It provides a simple means for monitoring irregularly distributed sections throughout a volume without the need to encode the whole volume. It offers the potential for increased signal-to-noise ratio if an appropriate basis is used for encoding. With a unique design of excitation pulses, it also appears possible to significantly reduce in-flow effects. An interleaved echo-planar imaging (EPI) sequence was adapted for non-Fourier encoding in the slice-select direction and was implemented on a conventional 1.5-Telsa system. The method was then used for functional mapping of the visual and motor areas where significant reduction of in-flow effect was demonstrated. This approach can be adapted to other imaging sequences that are used for fMRI, such as single-shot EPI.
Yoo
S S
SS
Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA.
Guttmann
C R
CR
Panych
L P
LP
D000328:Adult; D001921:Brain / Q000033:anatomy & histology; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged