Patent Number: 6,294,916

Title: NMR and ESR probes for closed loop control of gradient fields

Abstract: Magnetic resonance imaging apparatus uses magnetic field gradients X, Y, Zto spatially encode the magnetic signals arising from a patient on a couch2 in bore 1 of a main magnet. Thermal stresses arising from aggressivegradients during multiple acquisitions result in imperfectly repeatedgradients and resulting image artefacts. The invention uses a probe 4provided with a gradient coil set similar to that for imaging, and fed bycurrents derived from the imaging gradient coils, connected so as toproduce an opposing gradient surrounding an MR active substance in theprobe. This enables a probe with a sufficiently large amount of MR activesubstance to produce a useful signal to be used to monitor the gradient,while overcoming the de-phasing problem. which would otherwise occur.Closed loop control of gradients thereby becomes possible.

Inventors: Burl; Michael (Chagrin Falls, OH), Young; Ian Robert (Marlborough, GB)

Assignee:

International Classification:

Expiration Date: 09/25/2013