In vivo comparison of two through-plane MR velocity mapping methods: fast Fourier encoding and phase mapping.
Magnetic resonance imaging maps of velocity were acquired with a 1.5-T system in 10 subjects in a plane perpendicular to the main pulmonary artery. Velocity images were successively acquired with a method developed from Fourier-encoding velocity imaging (FEVI) principles with eight gradient steps and one excitation, and with two-point phase-subtraction mapping. Reconstruction in FEVI was implemented by zero-filling interpolation around the eight gradient steps and then around the four central steps. The methods were compared by using estimates of noise in velocity measurements based on the difference between the experimental map and a smooth fitted map. For the same acquisition time, FEVI with four encoding steps was more precise in velocity measurements than phase mapping. Precision was further increased by the use of eight encoding steps, but acquisition time was doubled.
Mousseaux
E
E
Centre Inter-Establissement de Resonance Magnetique, Université de Paris-Sud, Hôpital de Bicétre, France.
Idy-Peretti
I
I
Bittoun
J
J
Jolivet
O
O
Bourroul
E
E
Tardivon
A
A
Péronneau
P
P
Gaux
J C
JC
D000328:Adult; D016477:Artifacts; D001783:Blood Flow Velocity / Q000502:physiology; D001810:Blood Volume / Q000502:physiology; D002302:Cardiac Output / Q000502:physiology; D003971:Diastole; D005583:Fourier Analysis; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008875:Middle Aged; D011651:Pulmonary Artery / Q000502:physiology*; D012039:Regional Blood Flow / Q000502:physiology; D013599:Systole; D013997:Time Factors