ArticleMagnetic resonance imaging2017
Image-based gradient non-linearity characterization to determine higher-order spherical harmonic coefficients for improved spatial position accuracy in magnetic resonance imaging.
Article in Magnetic resonance imaging, 2017. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 13 papers.
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Who cites it
13 citing papers in PubMed.
- Review
- Quality assurance and temporal stability of a 1.5 T MRI scanner for MR-guided Photon and Particle Therapy.Zeitschrift fur medizinische Physik · 2025Article
- [Spherical measurement-based analysis of gradient nonlinearity in magnetic resonance imaging].Sheng wu yi xue gong cheng xue za zhi = Journal of biomedical engineering = Shengwu yixue gongchengxue zazhi · 2025Article
- Virtual phantom methodology for assessment of MRI distortion correction in high-precision stereotactic radiosurgery treatment planning.Frontiers in oncology · 2025Article
- Distortion-corrected image reconstruction with deep learning on an MRI-Linac.Magnetic resonance in medicine · 2023Article
- Rapid distortion correction enables accurate magnetic resonance imaging-guided real-time adaptive radiotherapy.Physics and imaging in radiation oncology · 2023Article
- MaxGIRF: Image reconstruction incorporating concomitant field and gradient impulse response function effects.Magnetic resonance in medicine · 2022Article
- MRI Distortion Correction and Robot-to-MRI Scanner Registration for an MRI-Guided Robotic System.IEEE access : practical innovations, open solutions · 2022Article
- First clinical experience of correcting phantom-based image distortion related to gantry position on a 0.35T MR-Linac.Journal of applied clinical medical physics · 2021Article
- Distortion-free imaging: A double encoding method (DIADEM) combined with multiband imaging for rapid distortion-free high-resolution diffusion imaging on a compact 3T with high-performance gradients.Journal of magnetic resonance imaging : JMRI · 2020Article
- MRI quality control for the Italian Neuroimaging Network Initiative: moving towards big data in multiple sclerosis.Journal of neurology · 2019Article
- Role and future of MRI in radiation oncology.The British journal of radiology · 2019Review
- Improving apparent diffusion coefficient accuracy on a compact 3T MRI scanner using gradient nonlinearity correction.Journal of magnetic resonance imaging : JMRI · 2018Article
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Authors and funding
10 authors.
Funding
Abstract
purposeSpatial position accuracy in magnetic resonance imaging (MRI) is an important concern for a variety of applications, including radiation therapy planning, surgical planning, and longitudinal studies of morphologic changes to study neurodegenerative diseases. Spatial accuracy is strongly influenced by gradient linearity. This work presents a method for characterizing the gradient non-linearity fields on a per-system basis, and using this information to provide improved and higher-order (9th vs. 5th) spherical harmonic coefficients for better spatial accuracy in MRI.
methodsA large fiducial phantom containing 5229 water-filled spheres in a grid pattern is scanned with the MR system, and the positions all the fiducials are measured and compared to the corresponding ground truth fiducial positions as reported from a computed tomography (CT) scan of the object. Systematic errors from off-resonance (i.e., B0) effects are minimized with the use of increased receiver bandwidth (±125kHz) and two acquisitions with reversed readout gradient polarity. The spherical harmonic coefficients are estimated using an iterative process, and can be subsequently used to correct for gradient non-linearity. Test-retest stability was assessed with five repeated measurements on a single scanner, and cross-scanner variation on four different, identically-configured 3T wide-bore systems.
resultsA decrease in the root-mean-square error (RMSE) over a 50cm diameter spherical volume from 1.80mm to 0.77mm is reported here in the case of replacing the vendor's standard 5th order spherical harmonic coefficients with custom fitted 9th order coefficients, and from 1.5mm to 1mm by extending custom fitted 5th order correction to the 9th order. Minimum RMSE varied between scanners, but was stable with repeated measurements in the same scanner.
conclusionsThe results suggest that the proposed methods may be used on a per-system basis to more accurately calibrate MR gradient non-linearity coefficients when compared to vendor standard corrections.
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