COMPARISON OF INVERSION-RECOVERY ASYMMETRICAL SPIN-ECHO EPI AND GRADIENT-ECHO EPI FOR BRAIN MOTOR ACTIVATION STUDY

An inversion recovery asymmetric spin-echo (IR-ASE) echo-planar imagin g (EPI) sequence has been developed for functional studies of the brai n, This technique uses an 180 degrees inversion pulse with a long inve rsion time (TI) to suppress the pulsatile cerebrospinal fluid and an a symmetric spin-echo readout to obtain activation signals from brain ca pillaries. Because gradient-echo sequences are most sensitive to large vessels, motor cortex activation studies using a gradient-echo techni que also were conducted for comparison with the IR-ASE method. The res ults suggest that the IR-ASE pulse sequence may be a useful complement to the gradient-echo technique for the study of neuronal activity of the human brain.