Abstract
A three-axis uniplanar gradient coil was designed and built to provide order-of-magnitude increases in gradient strength of up to 500 mT/m on the x- and y-axes, and 1000 mT/m for the z-axis at 640 A input over a limited FOV (∼16 cm) for superficial regions, compared to conventional gradient coils, with significant gradient strengths extending deeper into the body. The gradient set is practically accommodated in the bore of a conventional whole-body, cylindrical-geometry MRI scanner, and operated using standard gradient supplies. The design was optimized for gradient linearity over a restricted volume while accounting for the practical problems of torque and heating. Tests at 320 A demonstrated up to 420-mT/m gradients near the surface at efficiencies of up to 1.4 mT/m/A. A new true 2D gradient-nonlinearity correction algorithm was developed to rectify gradient nonlinearities and considerably expand the imageable volumes. The gradient system and correction algorithm were implemented in a standard 1.5T scanner and demonstrated by high-resolution imaging of phantoms and humans.
Original language | English (US) |
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Pages (from-to) | 134-143 |
Number of pages | 10 |
Journal | Magnetic resonance in medicine |
Volume | 58 |
Issue number | 1 |
DOIs | |
State | Published - Jul 2007 |
Keywords
- Gradient nonlinearity
- High-speed gradients
- Local gradients
- Peripheral nerve stimulation
- Planar gradients
ASJC Scopus subject areas
- Radiology Nuclear Medicine and imaging