Patent ID: 6023636
Filing Date: 2000-02-08
Classification: G01R

Abstract:
A method for determining a location of a positionable object in an examination subject by magnetic resonance comprising the steps of:(a) disposing an examination subject in magnetic field gradients while acquiring magnetic resonance signals comprising a reference image of at least one slice of the examination subject using a whole body antenna, and frequency coding said magnetic resonance signals in a first direction with alternating signs and phase coding said magnetic resonance signals in a second direction with alternating signs;(b) attaching at least one radio-frequency reception coil having a small sensitivity region to an object whose position is to be determined and acquiring magnetic resonance signals, in the presence of said magnetic field gradients while said reference image is acquired, from said radio-frequency reception coil, said magnetic resonance signals having a frequency/phase spectrum associated therewith, and identifying a current position of said object from said frequency/phase spectrum of said magnetic resonance signals;(c) defining a new slice position dependent on said current position of said object and updating said reference image, to obtain an updated reference image only by employing said new slice position in said updated reference image; and(d) multiply repeating steps (a), (b), and (c).