Reduction of flow- and eddy-currents-induced image artifacts in coronary magnetic resonance angiography using a linear centric-encoding SSFP sequence
- 作者：Xiaoming Bi ; Jaeseok Park ; Vibhas Deshp ; e ; Orl ; o Simonetti ; Gerhard Laub ; Debiao Li
- 关键词：Magnetic resonance angiography (MRA) ; Coronary arteries ; High-field imaging ; SSFP ; Flow ; Eddy currents
- 刊名：Magnetic Resonance Imaging
- 出版年：2007
- 期刊代码：188_0730725x
- 类别：med
- 出版时间：October 2007
- 卷：25
- 期：8
- 页码：1138-1147
- 文件大小：1007 K
摘要
Coronary magnetic resonance angiography (MRA) acquired using steady-state free precession (SSFP) sequences tends to suffer from image artifacts caused by local magnetic field inhomogeneities. Flow- and gradient-switching-induced eddy currents are important sources of such phase errors, especially under off-resonant conditions. In this study, we propose to reduce these image artifacts by using a linear centric-encoding (LCE) scheme in the phase-encoding (PE) direction. Abrupt change in gradients, including magnitude and polarity between consecutive radiofrequency cycles, is minimized using the LCE scheme. Results from numeric simulations and phantom studies demonstrated that signal oscillation can be markedly reduced using LCE as compared to conventional alternating centric-encoding (ACE) scheme. The image quality of coronary arteries was improved at both 1.5 and 3.0 T using LCE compared to those acquired using ACE PE scheme (1.5 T: ACE/LCE=2.2±0.8/3.0±0.6, P=.02; 3.0 T: ACE/LCE=2.1±1.1/3.0±0.8, P=.01). In conclusion, flow- and eddy-currents-induced imaging artifacts in coronary MRA using SSFP sequence can be markedly reduced with LCE acquisition of PE lines.