IMPROVING THE TEMPORAL RESOLUTION OF FUNCTIONAL MR-IMAGING USING KEYHOLE TECHNIQUES

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.