Superresolution parallel magnetic resonance imaging: Application to functional and spectroscopic imaging
Superresolution parallel magnetic resonance imaging: Application to functional and spectroscopic imaging
复制标题
DOI：
10.1016/j.neuroimage.2009.03.049
复制
发表时间：
2009-08-01
期刊：
影响因子：
5.7
通讯作者：
Posse, Stefan
中科院分区：
文献类型：
--
作者：
Otazo, Ricardo;Lin, Fa-Hsuan;Posse, Stefan
当线圈灵敏度在图像体素内变化时，标准并行磁共振成像 (MRI) 技术会出现残留混叠伪影。在这项工作中，提出了一种称为超分辨率 SENSE (SURE-SENSE) 的并行 MRI 方法，其中通过仅获取 k 空间的中心区域而不是增加整个 k 空间矩阵上的采样距离来执行加速，并且重建明确地基于体素内线圈灵敏度变化。在 SURE-SENSE 中，并行 MRI 重建被表述为超分辨率成像问题，其中使用以高空间分辨率获取的线圈灵敏度将用多个接收器线圈获取的低分辨率图像集合组合成具有更高空间分辨率的单个图像。传统梯度编码的有效加速由空间分辨率的增益给出，空间分辨率的增益由低分辨率图像体素内不同线圈灵敏度分布的变化程度决定。由于SURE-SENSE是不适定反问题，因此采用Tikhonov正则化来控制噪声放大。与标准 SENSE 不同，标准 SENSE 的加速度受限于相位编码维度，SURE-SENSE 允许沿所有编码方向加速 - 例如，2D 回波平面采集的二维加速度。 SURE-SENSE 特别适合低空间分辨率成像模式，例如光谱成像和高时间分辨率功能成像。介绍了使用 32 通道接收器线圈的二维加速在人脑回波平面功能和光谱成像中的应用。 (C) 2009 Elsevier Inc. 保留所有权利。
Standard parallel magnetic resonance imaging (MRI) techniques suffer from residual aliasing artifacts when the coil sensitivities vary within the image voxel. In this work, a parallel MRI approach known as Superresolution SENSE (SURE-SENSE) is presented in which acceleration is performed by acquiring only the central region of k-space instead of increasing the sampling distance over the complete k-space matrix and reconstruction is explicitly based on intra-voxel coil sensitivity variation. In SURE-SENSE, parallel MRI reconstruction is formulated as a superresolution imaging problem where a collection of low resolution images acquired with multiple receiver Coils are combined into a single image with higher spatial resolution using coil sensitivities acquired with high spatial resolution. The effective acceleration of conventional gradient encoding is given by the gain in spatial resolution, which is dictated by the degree of variation of the different coil sensitivity profiles within the low resolution image voxel. Since SURE-SENSE is an ill-posed inverse problem, Tikhonov regularization is employed to control noise amplification. Unlike standard SENSE, for which acceleration is constrained to the phase-encoding dimension/s, SURE-SENSE allows acceleration along all encoding directions - for example, two-dimensional acceleration of a 2D echo-planar acquisition. SURE-SENSE is particularly suitable for low spatial resolution imaging modalities such as spectroscopic imaging and functional imaging with high temporal resolution. Application to echo-planar functional and spectroscopic imaging in human brain is presented using two-dimensional acceleration with a 32-channel receiver coil. (C) 2009 Elsevier Inc. All rights reserved.