Fast angiography using selective inversion recovery.
We have developed an enhancement of selective inversion recovery that allows us to obtain high-resolution angiograms in reduced scan time. By applying several read pulses following each tagging inversion pulse, we can obtain several phase encodes in each cardiac cycle, thereby reducing the total scan time required for a complete image. Using this technique, high-resolution angiograms can be obtained in as little as 15 s. Because the phase encodes are collected in short bursts separated by long pauses, care must be taken to maintain uniform signal weighting across phase-encoding views and avoid ghosting. We use an increasing flip-angle sequence to equalize signal level weighting across the readouts. The phase encodes are collected in a special order to minimize ghosting. A postprocessing technique is used to further reduce signal nonuniformity between phase encodes. This fast angiography technique can significantly reduce artifacts due to patient motion during scanning and is especially useful for imaging vasculature in regions of the body where respiratory motion is a problem.
Wang
S J
SJ
Magnetic Resonance Systems Research Laboratory, Stanford University, California 94309.
Nishimura
D G
DG
Macovski
A
A
D000465:Algorithms; D000792:Angiography / Q000379:methods*; D001013:Aorta, Thoracic / Q000000981:diagnostic imaging; D002339:Carotid Arteries / Q000000981:diagnostic imaging; D006801:Humans; D008961:Models, Structural; D011856:Radiographic Image Enhancement / Q000379:methods*; D012815:Signal Processing, Computer-Assisted; D013382:Subtraction Technique; D013997:Time Factors