Local planar gradients with order-of-magnitude strength and speed advantage

Bulent Aksel, Luca Marinelli, Bruce D. Collick, Cornelius Von Morze, Paul A. Bottomley, Christopher J. Hardy

Research output: Contribution to journalArticlepeer-review

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 languageEnglish (US)
Pages (from-to)134-143
Number of pages10
JournalMagnetic resonance in medicine
Volume58
Issue number1
DOIs
StatePublished - Jul 2007

Keywords

  • Gradient nonlinearity
  • High-speed gradients
  • Local gradients
  • Peripheral nerve stimulation
  • Planar gradients

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging

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