Differentiation of spinal cord arteries and veins by time-resolved MR angiography.
OBJECTIVE
To dynamically resolve the inlet arteries and outlet veins of the spinal cord, particularly the Adamkiewicz artery (AKA) and great anterior radiculomedullary vein (GARV), using MR angiography (MRA).


METHODS
First, conventional two-phase angiography (acquisition time = 38-55 seconds) utilizing elliptic centric k-space ordering was applied to aortic-aneurysm patients. Changes of vessel intensity were compared between two subsequent dynamic phases. Computer modeling of bolus enhancement and k-space sampling was performed to demonstrate the relation between vessel enhancement, acquisition time, and vessel diameter. Second, time-resolved (TR, or "keyhole") angiography using a reduced number of phase-encoding steps was explored in healthy volunteers and aortic-aneurysm patients using acquisition times (range = 6-8.5 seconds) shorter than the spinal cord circulation time.


RESULTS
Using two-phase angiography the AKA and GARV were covisualized in the early phase, and contrast decreased for the AKA and increased for the GARV in most (70%) but not all cases. Computer modeling showed that the arteriovenous contrast strongly depended on vessel diameter, and complete separation was only obtained with short acquisition times. Using TR MR angiography (TR-MRA), complete temporal separation of the AKA and GARV was realized in all cases (100%).


CONCLUSIONS
The AKA and GARV can be completely separated by TR-MRA.
Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands.
Karolien
K
Jaspers
Robbert J
RJ
Nijenhuis
Walter H
WH
Backes
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003198:Computer Simulation; D003287:Contrast Media; D005260:Female; D019786:Gadolinium DTPA; D006801:Humans; D007091:Image Processing, Computer-Assisted; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D008875:Middle Aged; D013116:Spinal Cord / Q000098:blood supply*
D003287:Contrast Media; D019786:Gadolinium DTPA