MR angiography without subtraction

A new NMR method for producing angiograms with strong suppression of the static spin signal and without the need for subtraction is described and demonstrated. A velocity‐selective pulse sequence was implemented whereby the magnetization of all stationary spins is driven to the —z axis and is not detected, while maximizing the signal intensity of the moving spins. A theory of the method is presented and gives good agreement with experimental results obtained on a flow phantom. It is shown theoretically and experimentally that high‐quality velocity‐independent angiograms of the head and neck can be obtained with strong suppression of static spin signal when TR ∼ T1. The method can be extended to produce three‐dimensional angiograms. © 1991 Academic Press, Inc.