Imaging of cerebral activation at 1.5 T: optimizing a technique for conventional hardware.
OBJECTIVE
To empirically optimize a two-dimensional magnetic resonance (MR) imaging technique for detecting changes in signal intensity during cerebral activation with a standard clinical imager.


METHODS
Visual activation experiments were performed while imaging parameters were manipulated in a serial fashion, to test their effect on the percentage change in signal intensity (PCSI). The parameters tested were section thickness, echo time (TE), field of view (FOV), flip angle, radio-frequency (RF) spoiling, number of readout points, and number of signals averaged.


RESULTS
The PCSI for visual activation experiments was typically in the 1%-5% range. The best results were achieved with a small section thickness, long TE, and large FOV. Variations in other acquisition parameters had a negligible influence on the PCSI.


CONCLUSIONS
Good results can be obtained at functional MR imaging with standard 1.5-T hardware. Markedly improved results can be obtained by optimizing several key variables, namely, section thickness, TE, and FOV.
Thompson
R M
RM
Department of Diagnostic Radiology, Mayo Clinic, Rochester, MN.
Jack
C R
CR
Butts
K
K
Hanson
D P
DP
Riederer
S J
SJ
Ehman
R L
RL
Hynes
R W
RW
Hangiandreou
N J
NJ
D000328:Adult; D001921:Brain / Q000033:anatomy & histology* / Q000502:physiology; D002560:Cerebrovascular Circulation / Q000502:physiology*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000295:instrumentation / Q000379:methods*; D010775:Photic Stimulation; D012815:Signal Processing, Computer-Assisted; D014793:Visual Cortex / Q000033:anatomy & histology / Q000502:physiology