Balanced steady-state free precession with parallel imaging gives distortion-free fMRI with high temporal resolution
Balanced steady-state free precession with parallel imaging gives distortion-free fMRI with high temporal resolution
复制标题
DOI：
10.1016/j.mri.2010.07.007
复制
发表时间：
2011-01-01
影响因子：
2.5
通讯作者：
Kristoffersen, Anders
中科院分区：
文献类型：
--
作者：
Chappell, Michael;Haberg, Asta K.;Kristoffersen, Anders
对人脑功能的研究要求功能磁共振成像（MRI）朝着产生具有更小失真和更高时间和空间分辨率的图像的方向发展。本研究比较了带通平衡稳态自由旋进（bSSFP）采集与不带并行成像（PI），以研究PI与该脉冲序列相结合是否是功能MRI的可行选择。这种新颖的组合具有提供bSSFP的无失真优点和PI的减少的采集时间的潜力。扫描在Philips 3T Intera上进行，使用安装的bSSFP脉冲序列，带和不带灵敏度编码（SENSE）PI选项。这项任务是一个视觉闪烁的棋盘，观察窗覆盖了视觉皮层。对于受试者的每个时间过程，使用相同的手动绘制的感兴趣区域进行有和没有PI的灵敏度比较，并比较z分数汇总统计：z>2.3的体素数量，这些体素的平均值，它们的第90百分位数和它们的最大值。我们表明，PI大大提高了时间分辨率bSSFP，减少了一半以上的体积采集时间在这项研究中的0.67秒与3毫米各向同性体素。同时，与无PI相比，使用bSSFP的最大z评分在统计学上显著增加（P=.02）。这种改善可以从生理噪声的角度来理解，如噪声测量所示。这产生了观察到的功能时间序列的整体时间信噪比的增加，从而对PI的功能激活具有更高的灵敏度。这项研究首次证明了PI与bSSFP相结合，以实现无失真的功能图像，而不损失灵敏度和高时间分辨率的可能性。(C)2011 Elsevier Inc. All rights reserved.
Research on the functions of the human brain requires that functional magnetic resonance imaging (MRI) moves towards producing images with less distortion and higher temporal and spatial resolution. This study compares passband balanced steady-state free precession (bSSFP) acquisitions with and without parallel imaging (PI) to investigate whether combining PI with this pulse sequence is a viable option for functional MRI. Such a novel combination has the potential to offer the distortion-free advantages of bSSFP with the reduced acquisition time of PI. Scans were done on a Philips 3T Intera, using the installed bSSFP pulse sequence, both with and without the sensitivity encoding (SENSE) PI option. The task was a visual flashing checkerboard, and the viewing window covered the visual cortex. Sensitivity comparisons with and without PI were done using the same manually drawn region of interest for each time course of the subject, and comparing the z-score summary statistics: number of voxels with z>2.3, the mean of those voxels, their 90th percentile and their maximum value. We show that PI greatly improves the temporal resolution in bSSFP, reducing the volume acquisition time by more than half in this study to 0.67 s with 3-mm isotropic voxels. At the same time, a statistically significant increase was found for the maximum z-score using bSSFP with PI as compared to without it (P=.02). This improvement can be understood in terms of physiological noise, as demonstrated by noise measurements. This produces observed increases in the overall temporal signal to noise of the functional time series, giving greater sensitivity to functional activations with PI. This study demonstrates for the first time the possibility of combining PI with bSSFP to achieve distortion-free functional images without loss of sensitivity and with high temporal resolution. (C) 2011 Elsevier Inc. All rights reserved.