期刊
MAGNETIC RESONANCE IN MEDICINE
卷 50, 期 1, 页码 1-6出版社
JOHN WILEY & SONS INC
DOI: 10.1002/mrm.10501
关键词
projection reconstruction; radial imaging; gradient errors; gradient delay; compensation blips; reference scans; echo-planar imaging; magnitude back projection; linear phase
资金
- Intramural NIH HHS [Z01 HL004608-08] Funding Source: Medline
The projection reconstruction (PR) trajectory was investigated for the effect of gradient timing delays between the actual and requested start time of each physical gradient. Radial trajectories constructed with delayed gradients miss the center of k-space in an angularly dependent manner, causing effective echo times to vary with projection angle. The gradient timing delays were measured in phantoms, revealing delays on the x, y, and z gradients which differed by as much as 5 musec. Using this one-time calibration measurement, the trajectories were corrected for gradient delays by addition of compensatory gradient areas to the prephasers of the logical x and y readout gradients. Effective projection-to-projection echo time variability was reduced to less than 1 musec for all imaging orientations. Using corrected trajectories, artifacts were reduced in phantom images and in volunteer studies. This correction should potentiate greater clinical use of the PR trajectory. Magn Reson Med 50:1-6, 2003. Published 2003 Wiley-Liss, lnc.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据