Heberlein Keith, Hu Xiaoping
Emory University/Georgia Tech, Dept. of Biomedical Engineering, Biomedical Imaging Technology Center, Atlanta, GA 30322, USA.
Magn Reson Med. 2006 Mar;55(3):619-25. doi: 10.1002/mrm.20811.
This work describes an auto-calibrated method for parallel imaging with spiral trajectory. The method is a k-space approach where an interpolation kernel, accounting for coil sensitivity factors, is derived from experimental data and used to interpolate the reduced data set in parallel imaging to estimate the missing k-space data. For the case of spiral imaging, this interpolation kernel is defined along radial directions so that missing spiral interleaves can be estimated directly from neighboring interleaves. This kernel is invariant along the radial direction but varies azimuthally. Therefore, the k-space is divided into angular sectors and sector-specific kernels are used. It is demonstrated experimentally that relatively few sectors are sufficient for accurate reconstruction, allowing for efficient implementation. The interpolation kernels can be derived either from a separate calibration scan or self-calibration data available with a dual-density spiral acquisition. The reconstruction method is implemented with two sampling strategies and experimentally demonstrated to be robust.
这项工作描述了一种用于螺旋轨迹并行成像的自动校准方法。该方法是一种k空间方法，其中考虑线圈灵敏度因子的插值内核是从实验数据中推导出来的，并用于对并行成像中减少的数据集进行插值，以估计缺失的k空间数据。对于螺旋成像的情况，该插值内核沿径向定义，以便可以直接从相邻的交错中估计缺失的螺旋交错。该内核在径向方向上是不变的，但在方位角上会变化。因此，k空间被划分为角扇区，并使用特定扇区的内核。实验表明，相对较少的扇区就足以进行准确的重建，从而实现高效的实现。插值内核可以从单独的校准扫描或双密度螺旋采集提供的自校准数据中推导出来。该重建方法通过两种采样策略实现，并通过实验证明是稳健的。
