Multiple-readout selective inversion recovery angiography.
We have developed a variation of selective inversion recovery (SIR) angiography that allows us to obtain a collection of several angiograms within the same acquisition time previously required to obtain a single image. In basic SIR, a single readout is performed after the tagging inversion pulse. In multiple-readout SIR, a succession of readout pulses is applied following the inversion pulse. By varying the gradients appropriately during the successive readouts, we can obtain a set of multiple projection-angle angiograms, or, by appropriately spacing the readouts throughout the cardiac cycle, we can obtain a set of time-resolved angiograms. This technique allows us to obtain additional spatial or temporal information without increasing total scan time. A sequence of increasing flip-angle read pulses is used to maintain a constant signal level across the images. A trade-off exists between SNR and the number of images acquired.
Wang
S J
SJ
Magnetic Resonance Systems Research Laboratory, Stanford University, California 94305.
Nishimura
D G
DG
Macovski
A
A
D001808:Blood Vessels / Q000033:anatomy & histology*; D002339:Carotid Arteries / Q000033:anatomy & histology; D004562:Electrocardiography; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008954:Models, Biological; D012039:Regional Blood Flow; D012212:Rheology; D013382:Subtraction Technique