Department of Biomedical Engineering, Zhejiang University, Hangzhou 310027, China ; Key Laboratory for Biomedical Engineering of Education Ministry of China, China ; Department of Psychiatry, Brain Imaging Center, University of Colorado School of Medicine, Aurora, CO, USA.
Department of Psychiatry, Brain Imaging Center, University of Colorado School of Medicine, Aurora, CO, USA.
Comput Math Methods Med. 2014;2014:973972. doi: 10.1155/2014/973972. Epub 2014 Mar 9.
To investigate the advantages of reducing the partial volume effect (PVE) to enhance the detection of the BOLD signal in fMRI.
A linear phase term was added in k-space to obtain half-voxel shifting of 64 × 64 T2*-weighted echo-planar images. Three sets of image data shifted in the x, y, and diagonal direction, respectively, are combined with the original 64 × 64 data to form the 128 × 128 voxel-shifted interpolated data.
A simulation of a synthetic fMRI dataset shows that the voxel-shifted interpolation (VSI) can increase the t-score up to 50% in single-voxel activations. An fMRI study (n = 7) demonstrates that 20.4% of the interpolated voxels have higher t-scores than their nearest neighboring voxels in the original maps. The average increase of the t-score in these interpolated voxels is 13.3%.
VSI yields increased sensitivity in detecting voxel-size BOLD activations, improved spatial accuracy of activated regions, and improved detection of the peak BOLD signal of an activated region. VSI can potentially be used as an alternative to the high-resolution fMRI studies in which reduction in SNR and increase in imaging time become prohibitive.
研究减少部分容积效应（PVE）以增强 fMRI 中 BOLD 信号检测的优势。
在 k 空间中添加线性相位项，以获得 64×64 T2*-加权回波平面图像的半像素移位。分别在 x、y 和对角线方向上移位三组图像数据，并将其与原始 64×64 数据组合形成 128×128 像素移位插值数据。
对合成 fMRI 数据集的模拟表明，像素移位插值（VSI）可使单像素激活的 t 值提高高达 50%。一项 fMRI 研究（n=7）表明，在原始图中，有 20.4%的插值体素的 t 值高于其最近邻体素。这些插值体素的 t 值平均增加 13.3%。
VSI 提高了检测体素大小 BOLD 激活的灵敏度，改善了激活区域的空间准确性，并提高了激活区域的峰值 BOLD 信号的检测能力。VSI 可作为替代高分辨率 fMRI 研究的方法，在高分辨率 fMRI 研究中，信噪比的降低和成像时间的增加变得不可行。
