Oval gradient coils for an open magnetic resonance imaging system with a vertical magnetic field

Abstract

Existing open magnetic resonance imaging (MRI) systems use biplanar gradient coils for the spatial encoding of signals. We propose using novel oval gradient coils for an open vertical-field MRI. We designed oval gradients for a 0.3T open MRI system and showed that such a system could outperform a traditional biplanar gradient system while maintaining adequate gradient homogeneity and subject accessibility. Such oval gradient coils would exhibit high efficiency, low inductance and resistance, and high switching capability. Although the designed oval Y and Z coils showed more heat dissipation and less cooling capability than biplanar coils with the same gap, they showed an efficient heat-dissipation path to the surrounding air, which would alleviate the heat problem. The performance of the designed oval-coil system was demonstrated experimentally by imaging a human hand.

Development of a Car-mounted Mobile MR Imaging System for Diagnosis of Sports-related Wrist Injury

“…1b ) (200 kg, 16-cm gap, 44 cm × 50 cm × 36 cm, 10-cm-diameter spherical volume for imaging; NEOMAX Engineering Japan, Gunma, Japan). The gradient field coils were designed using singular value decomposition and genetic algorithms 11 and were fabricated on a printed circuit board. The gradient efficiency was 1.72( x ), 1.72( y ), 3.33( z ) mT/m/A.…”

Low‐field MRI: An MR physics perspective

“…There have been many publications outlining advances in the design of such bi-planar gradients. [27][28][29] In terms of gradient performance, typical numbers for modern-day gradients on the "whole body" low-field MRI systems are inductances on the order of 300-500 μH, resistances of 3-4 Ω, and efficiencies of 4-8 mT/m/A. Maximum gradient strengths for water-cooled gradient coils are on the order of 25 mT/m with a slew rate of 50 T/m/s.…”

“…), referred to as bi‐planar gradient coils, which are attached to the two opposing magnetic poles: this configuration maximizes the open space in the magnet gap. There have been many publications outlining advances in the design of such bi‐planar gradients …”