MR angiography with adiabatic flow excitation.
A new method of magnetic resonance (MR) angiography is presented that produces signal from flowing spins and suppresses that from stationary spins by means of a flow excitation pulse sequence consisting of adiabatic 90 degrees and 180 degrees radio-frequency (RF) pulses interleaved with flow-dephasing gradient lobes. Stationary spins are refocused along the z axis, while flowing spins are dephased by the gradient lobes and generate a transverse component that can be measured directly to produce the angiogram. Adiabatic RF pulses and unipolar gradient lobes give the pulse sequence a high degree of immunity to RF and magnetic field inhomogeneity. The pulse sequence can be successfully applied with a transmit/receive surface coil. The disadvantage of adiabatic RF pulses is that their long duration makes it difficult to suppress the signal of stationary spins with short T2.
Lee
J N
JN
Department of Radiology, School of Medicine, University of Utah, Salt Lake City 84132.
Parker
D L
DL
D001783:Blood Flow Velocity; D001808:Blood Vessels / Q000033:anatomy & histology*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008955:Models, Cardiovascular; D008961:Models, Structural