Detection and compensation of periodic motion in magnetic particle imaging

Journal
IEEE transactions on medical imaging  
Volume
36
Issue
7
Start Page
1511
End Page
1521
Citation
IEEE Transactions on Medical Imaging 7 (36): 1511-1521 (2017)
Publisher DOI
10.1109/TMI.2017.2666740
Scopus ID
2-s2.0-85028443162
Publisher
IEEE
The temporal resolution of the tomographic imaging method magnetic particle imaging (MPI) is remarkably high. The spatial resolution is degraded for measured voltage signal with low signal-to-noise ratio, because the regularization in the image reconstruction step needs to be increased for system-matrix approaches and for deconvolution steps in x-space approaches. To improve the signal-to-noise ratio, blockwise averaging of the signal over time can be advantageous. However, since block-wise averaging decreases the temporal resolution, it prevents resolving the motion. In this paper, a framework for averaging motion-corrupted MPI raw data is proposed. The motion is considered to be periodic as it is the case for respiration and/or the heartbeat. The same state of motion is thus reached repeatedly in a time series exceeding the repetition time of the motion and can be used for averaging. As the motion process and the acquisition process are, in general, not synchronized, averaging of the captured MPI raw data corresponding to the same state of motion requires to shift the starting point of the individual frames. For high-frequency motion, a higher frame rate is potentially required. To address this issue, a binning method for using only parts of complete frames from a motion cycle is proposed that further reduces the motion artifacts in the final images. The frequency of motion is derived directly from the MPI raw data signal without the need to capture an additional navigator signal. Using a motion phantom, it is shown that the proposed method is capable of averaging experimental data with reduced motion artifacts. The methods are further validated on in-vivo data from mouse experiments to compensate the heartbeat.
Subjects
Biomedical imaging
Motion artifacts
Motion compensation
Motion detection
DDC Class
600: Technik
610: Medizin
Funding(s)
Ganzkörper Magnetic-Particle-Imaging Messsequenzen  
More Funding Information
Supported in part by the German Research Foundation through DFGunder Grant AD 125/5-1 and Grant KN 1108/2-1 and in part by NIH under Grant NIH 2R42EB013520-02A1 and Grant NIH 1R24-MH109085.