O. Speck et J. Hennig, FUNCTIONAL IMAGING BY I-0-PARAMETER AND T-2-ASTERISK-PARAMETER MAPPING USING MULTIIMAGE EPI, Magnetic resonance in medicine, 40(2), 1998, pp. 243-248
A new functional imaging method has been developed and used to measure
T-2- and initial intensity (I-O)-parameter maps of multiple slices d
uring activation of the cortex with high temporal resolution. Multiple
echo-planar images (EPIs) are read out after a single excitation of t
he spin system, leading to several images with increasing effective ec
ho times. Changes induced by primary visual stimulation in T-2 and I-
O were measured in eight subjects. Although stimulation-induced increa
ses in I-O only occurred at short repetition times, T-2 increased fro
m 57.3 to 60.9 ms on average. The method combines the high stability o
f a single shot EPI experiment with the high information content of a
multiecho acquisition. In addition, stimulation-induced changes in inf
low can be easily separated from true blood oxygenation level dependen
t (BOLD) signal changes.