On improving temporal and spatial resolution of 3D contrast-enhanced body MR angiography with parallel imaging.

Abstract

Use of a parallel imaging technique to improve temporal and spatial resolution at three-dimensional contrast-enhanced magnetic resonance (MR) angiography was investigated. Thirty experiments were performed in five groups of healthy subjects. In groups 1-3, the technique was used to improve imaging speed by a factor of two or four while maintaining spatial resolution. Contrast agent concentration was two to four times higher than at standard MR angiography, to take advantage of the faster imaging speed. In groups 4 and 5, the technique was used to double spatial resolution in the phase-encoding direction while maintaining imaging speed and contrast agent concentration. At a two to four times faster imaging speed, signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) almost equaled those at standard MR angiography, likely a result of increased contrast agent concentration. The use of parallel imaging to achieve higher spatial resolution was also proved feasible, but with substantial reduction in SNR and CNR.