Jh. Gao et al., IMPROVING THE TEMPORAL RESOLUTION OF FUNCTIONAL MR-IMAGING USING KEYHOLE TECHNIQUES, Magnetic resonance in medicine, 35(6), 1996, pp. 854-860
Using a keyhole technique, it is shown that the data acquisition rate
of gradient-echo imaging for functional MRI (fMRI) studies can be incr
eased substantially, The resulting enhancement of the temporal resolut
ion of fMRIs was accomplished without modifying the hardware of a conv
entional MRI system, High spatial resolution fMRI images were first co
llected with conventional full k-space acquisition acid image reconstr
uction, Using the same data set, simulation reconstruction using the k
eyhole principle and zero-padding were performed for comparison with t
he full k-space reconstruction. No significant changes were found for
fMRI images generated from the keyhole technique with a data sharing p
rofile of 50% of the k-space, As k-space data sharing profiles increas
ed to 75 and 87.5%, the keyhole fMRI images began to show only modest
changes in activation intensity and area compared with the standard im
ages, In contrast, zero-padding fMRI images produced a significant dis
parity both in activation intensity and area relative to the truly hig
h-resolution fMRI images. The keyhole technique's ability to retain th
e intensity and area of fMRI information, while substantially reducing
acquisition time, makes it a promising method for fMRI studies.