Sub-millimeter fMRI at 1.5 Tesla: correlation of high resolution with low resolution measurements.
Functional magnetic resonance imaging of the visual cortex with an in-plane resolution of 0.4 x 0.4 mm2 was performed using a simple visual stimulus resulting in clear maps of activation. A collapsing filter was used to compare these high-resolution images with low-resolution images collected during the same session. A good correspondence between the high- and low-resolution functional maps was found with respect to the center of localization of activation. However, only 20% of the size of activated areas in the low-resolution experiment was observed at high resolution, which was partly caused by the difference in signal-to-noise ratio. The high-resolution images produce signal changes much higher than the low-resolution images due to reduced partial volume effects. Additionally, the high-resolution functional maps were compared with detailed anatomical and venous information. The activated areas were predominantly observed at venous vessels within the sulci with a diameter on the order of the pixel size.
Hoogenraad
F G
FG
Department of Clinical Physics and Informatics, University Hospital Vrije Universiteit, Amsterdam, The Netherlands.
Hofman
M B
MB
Pouwels
P J
PJ
Reichenbach
J R
JR
Rombouts
S A
SA
Haacke
E M
EM
D000328:Adult; D016477:Artifacts; D001931:Brain Mapping / Q000379:methods*; D005189:False Positive Reactions; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D010690:Phlebography / Q000379:methods; D012016:Reference Values; D012680:Sensitivity and Specificity; D014793:Visual Cortex / Q000033:anatomy & histology* / Q000098:blood supply / Q000502:physiology*