Activation of the sensorimotor cortex at 1.0 T: comparison of echo-planar and gradient-echo imaging.
OBJECTIVE
The increasing demand for the clinical application of functional MR imaging raises the question of whether this technique can be routinely performed on 1.0-T MR scanners. To this end, we assessed the feasibility of functional MR imaging at 1.0 T.


METHODS
Healthy volunteers were scanned during the performance of a motor task. Functional data were acquired with echo-planar imaging (EPI) and with gradient-echo (GRE) and dual-echo GRE sequences. The signal intensity variations of the EPI and GRE sequences were compared, and the influence of inflow and blood oxygen level-dependent (BOLD) effects on the signal variations was assessed with the dual-echo GRE sequences.


RESULTS
In 11 of the 12 subjects we found activation in the primary motor cortex with both the GRE and EPI sequences. Active voxels had a significantly higher mean percentage of signal changes with the EPI sequence than with the GRE sequence (EPI: 1% to 6.1%, mean 2.4%; GRE: 1% to 4.5%, mean 1.9%). The EPI sequence was less sensitive to motion artifacts and enabled imaging of a larger brain volume in a shorter time. With a dual-echo sequence we found an increasing contribution of inflow effect with an increasing percentage of signal changes.


CONCLUSIONS
Functional MR imaging of the sensorimotor cortex can be routinely performed at 1.0 T.
Department of Radiology, University Hospital Nijmegen, The Netherlands.
B F
BF
van der Kallen
L J
LJ
van Erning
M W
MW
van Zuijlen
H
H
Merx
H O
HO
Thijssen
D000328:Adult; D001143:Arousal / Q000502:physiology*; D016477:Artifacts; D001931:Brain Mapping / Q000295:instrumentation*; D017352:Echo-Planar Imaging / Q000295:instrumentation*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000295:instrumentation; D008279:Magnetic Resonance Imaging / Q000295:instrumentation*; D008297:Male; D009044:Motor Cortex / Q000502:physiology*; D009048:Motor Skills / Q000502:physiology; D012016:Reference Values; D012680:Sensitivity and Specificity; D013003:Somatosensory Cortex / Q000502:physiology*