Field camera versus phantom-based measurement of the gradient system transfer function (GSTF) with dwell time compensation
| Autor: | Tobias Wech, Herbert Köstler, Julian A. J. Richter, Thorsten Bley, Adrienne E. Campbell-Washburn, Ralf Ringler, M. Stich |
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| Rok vydání: | 2020 |
| Předmět: |
Frequency response
Biomedical Engineering Biophysics Iterative reconstruction Residual Transfer function Article Imaging phantom 030218 nuclear medicine & medical imaging Compensation (engineering) 03 medical and health sciences Imaging Three-Dimensional 0302 clinical medicine Humans Radiology Nuclear Medicine and imaging Computer vision Retrospective Studies Physics Phantoms Imaging business.industry Magnetic Resonance Imaging Dwell time Trajectory Artificial intelligence Artifacts business Algorithms 030217 neurology & neurosurgery |
| Zdroj: | Magn Reson Imaging |
| ISSN: | 0730-725X |
| DOI: | 10.1016/j.mri.2020.06.005 |
| Popis: | PURPOSE: The gradient system transfer function (GSTF) can be used to describe the dynamic gradient system and applied for trajectory correction in non-Cartesian MRI. This study compares the field camera and the phantom-based methods to measure the GSTF and implements a compensation for the difference in measurement dwell time. METHODS: The self-term GSTFs of a MR system were determined with two approaches: 1) using a dynamic field camera and 2) using a spherical phantom-based measurement with standard MR hardware. The phantom-based GSTF was convolved with a box function to compensate for the dwell time dependence of the measurement. The field camera and phantom-based GSTFs were used for trajectory prediction during retrospective image reconstruction of 3D wave-CAIPI phantom images. RESULTS: Differences in the GSTF magnitude response were observed between the two measurement methods. For the wave-CAIPI sequence, this led to deviations in the GSTF predicted trajectories of 4% compared to measured trajectories, and residual distortions in the reconstructed phantom images generated with the phantom-based GSTF. Following dwell-time compensation, deviations in the GSTF magnitudes, GSTF-predicted trajectories, and resulting image artifacts were eliminated (< 0.5% deviation in trajectories). CONCLUSION: With dwell time compensation, both the field camera and the phantom-based GSTF self-terms show negligible deviations and lead to strong artifact reduction when they are used for trajectory correction in image reconstruction. |
| Databáze: | OpenAIRE |
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