A spiral, bi-planar gradient coil design for open magnetic resonance imaging

Article type: Research Article

Authors: Zhang, Peng^a | Shi, Yikai^a | Wang, Wendong^{a; *} | Wang, Yaohui^b

Affiliations: [a] School of Mechanical Engineering, Northwestern Polytechnical University, Xi’an, Shaanxi, China | [b] School of Medicine, Southern China University of Technology, Guangzhou, Guangdong, China

Correspondence: [*] Corresponding author: Wendong Wang, School of Mechanical Engineering, Northwestern Polytechnical University, Xi’an, Shaanxi 710072, China. Tel.: +86 029 88494893; Fax: +86 029 88494893; E-mail: wdwang@nwpu.edu.cn.

Abstract: PURPOSE: To design planar gradient coil for MRI applications without discretization of continuous current density and loop-loop connection errors. METHODS: In the new design method, the coil current is represented using a spiral curve function described by just a few control parameters. Using a proper parametric equation set, an ensemble of spiral contours is reshaped to satisfy the coil design requirements, such as gradient linearity, inductance and shielding. RESULTS: In the given case study, by using the spiral coil design, the magnetic field errors in the imaging area were reduced from 5.19% (non-spiral design) to 4.47% (spiral design) for the transverse gradient coils, and for the longitudinal gradient coil design, the magnetic field errors were reduced to 5.02% (spiral design). The numerical evaluation shows that when compared with conventional wire loop, the inductance and resistance of spiral coil was reduced by 11.55% and 8.12% for x gradient coil, respectively. CONCLUSION: A novel spiral gradient coil design for biplanar MRI systems, the new design offers better magnetic field gradients, smooth contours than the conventional connected counterpart, which improves manufacturability.

Keywords: Spiral function, gradient coil, discrete wire method, open MRI, magnetic field

DOI: 10.3233/THC-171081

Journal: Technology and Health Care, vol. 26, no. 1, pp. 119-132, 2018