Institute of Medical Engineering, University of Lübeck, 23562, Lübeck, Germany.
Section for Biomedical Imaging, University Medical Center Hamburg-Eppendorf, 22529, Hamburg, Germany.
Sci Rep. 2020 Oct 28;10(1):18432. doi: 10.1038/s41598-020-75122-5.
Image reconstruction in magnetic particle imaging is often performed using a system matrix based approach. The acquisition of a system matrix is a time-consuming calibration which may take several weeks and thus, is not feasible for a clinical device. Due to hardware characteristics of the receive chain, a system matrix may not even be used in similar devices but has to be acquired for each imager. In this work, a dedicated device is used for measuring a hybrid system matrix. It is shown that the measurement time of a 3D system matrix is reduced by 96%. The transfer function of the receive chains is measured, which allows the use of the same system matrix in multiple devices. Equivalent image reconstruction results are reached using the hybrid system matrix. Furthermore, the inhomogeneous sensitivity profile of receive coils is successfully applied to a hybrid system matrix. It is shown that each aspect of signal acquisition in magnetic particle imaging can be taken into account using hybrid system matrices. It is favourable to use a hybrid system matrix for image reconstruction in terms of measurement time, signal-to-noise ratio and discretisation.
在磁粒子成像中，图像重建通常采用基于系统矩阵的方法。系统矩阵的获取是一个耗时的校准过程，可能需要数周时间，因此对于临床设备来说是不可行的。由于接收链的硬件特性，类似的设备甚至可能不使用系统矩阵，而必须为每个成像仪获取系统矩阵。在这项工作中，使用专用设备来测量混合系统矩阵。结果表明，3D 系统矩阵的测量时间减少了 96%。测量了接收链的传递函数，允许在多个设备中使用相同的系统矩阵。使用混合系统矩阵可以达到等效的图像重建结果。此外，成功地将接收线圈的不均匀灵敏度分布应用于混合系统矩阵。结果表明，磁粒子成像中的每个信号采集方面都可以使用混合系统矩阵来考虑。从测量时间、信噪比和离散化的角度来看，使用混合系统矩阵进行图像重建是有利的。
