Qualitative mapping of cerebral blood flow and functional localization with echo-planar MR imaging and signal targeting with alternating radio frequency.
OBJECTIVE
To create qualitative maps of cerebral blood flow (CBF) with the EPISTAR (echo-planar imaging and signal targeting with alternating radio frequency) technique.


METHODS
The EPISTAR technique was performed in a pig model of hypercapnia and then tested in 26 volunteers by using various paradigms for cortical activation. Echo-planar images were acquired with and without use of a radio-frequency inversion pulse applied to inflowing arterial spins. A qualitative map of CBF was then created by subtracting the image obtained without the radio-frequency pulse from that obtained with the radio-frequency pulse.


RESULTS
Progressively more distal portions of the tagged vessels were seen as the inflow time was lengthened until cortical enhancement was seen for inflow times of approximately 1 second or longer. Signal intensity increases from rest to sensorimotor activation ranged from 13% to 193%. CBF changes in the motor strip, primary visual cortex, and the motor area for eye movements were well localized to the cortical gray matter ribbon.


CONCLUSIONS
The EPISTAR technique is a rapid, noninvasive means for creating qualitative maps of CBF.
Edelman
R R
RR
Department of Radiology, Beth Israel Hospital, Boston, MA 02215.
Siewert
B
B
Darby
D G
DG
Thangaraj
V
V
Nobre
A C
AC
Mesulam
M M
MM
Warach
S
S
D000818:Animals; D001931:Brain Mapping; D002560:Cerebrovascular Circulation; D017352:Echo-Planar Imaging; D005133:Eye Movements; D006801:Humans; D006935:Hypercapnia / Q000503:physiopathology; D009044:Motor Cortex / Q000502:physiology; D013552:Swine; D014793:Visual Cortex / Q000502:physiology