Feng Hanhua, Gu Hong, Silbersweig David, Stern Emily, Yang Yihong
Department of Psychiatry, Weill Medical College of Cornell University, New York, NY 10021, USA.
IEEE Trans Med Imaging. 2003 Aug;22(8):925-32. doi: 10.1109/TMI.2003.815902.
A novel single-shot trapezoidal-gradient-based Lissajous trajectory is described and implemented on a 3-tesla magnetic resonance (MR) scanner. A feature of this trajectory is that its sampling points are located on a nonequidistant rectangular grid, which permits the usage of one-dimensional optimal algorithms to increase the robustness and speed of image reconstruction. Another advantage of the trajectory is that two images with different effective echo times can be obtained within a single excitation, which might be used for fast T2* mapping, in functional MR imaging scanning of brain activity associated with mental processes. Potential artifacts in reconstructed images were investigated and methods for suppressing these artifacts were developed. Experiments on normal subjects at rest and during brain activation were performed to demonstrate the feasibility of the new sequence.
本文描述了一种基于单次梯形梯度的新型李萨如轨迹，并在3特斯拉磁共振（MR）扫描仪上实现。该轨迹的一个特点是其采样点位于非等距矩形网格上，这允许使用一维优化算法来提高图像重建的稳健性和速度。该轨迹的另一个优点是可以在单次激发内获得具有不同有效回波时间的两幅图像，这可用于快速T2*映射，以及与心理过程相关的脑活动功能磁共振成像扫描。研究了重建图像中的潜在伪影，并开发了抑制这些伪影的方法。对静息和脑激活状态下的正常受试者进行了实验，以证明新序列的可行性。
