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MR angiography of the pelvis with variable velocity encoding and a phased-array coil
J S Swan1, T M Grist, D M Weber
1Department of Radiology, University of Wisconsin Clinical Science Center, Madison 53792.
Purpose:
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.
Materials And 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.
Conclusion:
Use of a phased-array coil and variable velocity encoding improves depiction of segmental vascular anatomic structures of the pelvis.