MR-ANGIOGRAPHY OF THE PELVIS WITH VARIABLE VELOCITY ENCODING AND A PHASED-ARRAY COIL

PURPOSE: To evaluate the feasibility of an automated variable velocity -encoding sequence and improve the signal-to-noise ratio (S/N) on magn etic resonance angiograms with use of phase contrast and a pelvic phas ed-array coil. MATERIALS AND METHODS: Three cardiac-gated, two-dimensi onal (2D), phase-contrast (PC) sequences were evaluated in 10 healthy subjects. A 2D gated PC sequence with variable velocity encoding (velo city-optimized phase contrast [VOPC]) was compared with gated 2D PC se quences performed with high or low constant velocity encoding. S/Ns in VOPC images obtained with a pelvic phased-array coil were compared wi th those in VOPC images obtained with a body coil. RESULTS: Two blinde d readers preferred VOPC for simultaneous display of large and small b lood vessels in one acquisition compared with constant low (P = .0105) and high (P = .0067) velocity encoding and for overall image interpre tation. VOPC images obtained with the pelvic coil had a 68%-100% bette r S/N compared with those obtained with the body coil. CONCLUSION: Use of a phased-array coil and variable velocity encoding improves depict ion of segmental vascular anatomic structures of the pelvis.