The functional scout image: immediate mapping of cortical function at 4 Tesla using receiver phase cycling.

A rapid method of generating functional scout images to map cortical activity is presented. Maps were produced immediately "on-line" on the scanner's console using fast low-angle shot gradient-recalled echo and echo-planar imaging sequences without special hardware. To demonstrate the technique, raw data collected during photic stimulation and dark control periods were subtracted through phase alternation of the receiver with constant transmitted radio frequency phase. A blood oxygen level-dependent signal difference map was produced by magnitude reconstruction of the resulting complex-difference data. Maps improved in contrast with an increasing number of stimulation-control cycles and showed similar areas of activation to traditional fMRI processing methods. Such a functional scout procedure allows rapid localization of brain function within the anatomical region of interest. From these functional scout images, slices or voxels may be planned by using the scanner manufacturers prescription tools for further specialized studies.