The recently developed single-element surface rotating radio-frequency coil (RRFC) for magnetic resonance imaging (MRI) is able to acquire signals from around the subject in the manner of a multi-coil array, while exhibiting simplified construction and no coil size restrictions. Herein, we present a novel image reconstruction algorithm for data acquired with the RRFC, which we label WARF (a weighted-sum approach to radial MRI image reconstruction with a rotating RF coil). The algorithm approaches the reconstruction problem by considering each image pixel to be a weighted sum of all acquired k-space data, which is already the case implicitly in several established methods. The problem is thus posed as one of solving for the appropriate weights directly. The theory underlying WARF is presented, and several measures to improve the computational efficiency of a practical implementation are considered. We note that while still computationally expensive, the calculation of the weights themselves would not necessarily need to be repeated each time the algorithm is applied. MR data are simulated for imaging schemes involving the rotating RF coil with both ideal and variable angular velocities, and for the case where the k-space locations of the radial trajectory are deviated from their intended positions. The WARF reconstruction algorithm is applied to each simulated data set, and compared with reconstructions from existing methods, where it is seen to demonstrate a robustness to velocity variation and the suppression of artefacts arising from a deviated trajectory. Finally, WARF is applied to experimental rotating RF coil data, where it is shown to yield good quality images.

中文翻译：

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WARF：使用旋转射频线圈进行径向 MRI 图像重建的加权求和方法

最近开发的用于磁共振成像 (MRI) 的单元件表面旋转射频线圈 (RRFC) 能够以多线圈阵列的方式从对象周围获取信号，同时具有简化的结构和没有线圈尺寸限制. 在这里，我们提出了一种新的图像重建算法，用于使用 RRFC 采集的数据，我们将其标记为 WARF（一种使用旋转射频线圈进行径向 MRI 图像重建的加权和方法）。该算法通过将每个图像像素视为所有获取的 k 空间数据的加权和来解决重建问题，这在几种已建立的方法中已经隐含地存在。因此，该问题被视为直接求解适当权重的问题之一。提出了 WARF 的基础理论，并考虑了几种提高实际实现计算效率的措施。我们注意到，虽然在计算上仍然很昂贵，但每次应用算法时不一定需要重复权重本身的计算。MR 数据针对涉及具有理想角速度和可变角速度的旋转 RF 线圈的成像方案以及径向轨迹的 k 空间位置偏离其预期位置的情况进行了模拟。WARF 重建算法应用于每个模拟数据集，并与现有方法的重建进行比较，可以看出它对速度变化的鲁棒性和对偏离轨迹产生的伪影的抑制。最后，将WARF应用于实验旋转射频线圈数据，