MR angiography of the pelvis with variable velocity encoding and a phased-array coil.
OBJECTIVE
To evaluate the feasibility of an automated variable velocity-encoding sequence and improve the signal-to-noise ratio (S/N) on magnetic resonance angiograms with use of phase contrast and a pelvic phased-array coil.


METHODS
Three cardiac-gated, two-dimensional (2D), phase-contrast (PC) sequences were evaluated in 10 healthy subjects. A 2D gated PC sequence with variable velocity encoding (velocity-optimized phase contrast [VOPC]) was compared with gated 2D PC sequences performed with high or low constant velocity encoding. S/Ns in VOPC images obtained with a pelvic phased-array coil were compared with those in VOPC images obtained with a body coil.


RESULTS
Two blinded readers preferred VOPC for simultaneous display of large and small blood vessels in one acquisition compared with constant low (P = .0105) and high (P = .0067) velocity encoding and for overall image interpretation. VOPC images obtained with the pelvic coil had a 68%-100% better S/N compared with those obtained with the body coil.


CONCLUSIONS
Use of a phased-array coil and variable velocity encoding improves depiction of segmental vascular anatomic structures of the pelvis.
Swan
J S
JS
Department of Radiology, University of Wisconsin Clinical Science Center, Madison 53792.
Grist
T M
TM
Weber
D M
DM
Sproat
I A
IA
Wojtowycz
M M
MM
D001783:Blood Flow Velocity; D001808:Blood Vessels / Q000033:anatomy & histology*; D005240:Feasibility Studies; D005263:Femoral Artery / Q000033:anatomy & histology / Q000502:physiology; D006801:Humans; D007083:Iliac Artery / Q000033:anatomy & histology / Q000502:physiology; D008279:Magnetic Resonance Imaging / Q000295:instrumentation / Q000379:methods*; D010388:Pelvis / Q000098:blood supply*