Magnetic resonance equipment for the production of images of a test object

Claim 1

Apparatus for producing images of a test object using nuclear magnetic resonance, at least a portion said test object being subject to physical motion, said apparatus comprising: (a) first means for applying magnetic primary and gradient fields to the test object and for detecting deflection of nuclear spins of the test object from their equilibrium position by a radio-frequency magnetic excitation pulse, said first means producing a plurality of time-sequential measurement signals representative of said nuclear spin deflection in response to a respective plurality of excitation pulses time-sequentially applied with corresponding gradient fields; (b) second means, responsive to said produced measurement signals, for calculating an image of a cross-sectional slice of the test object by Fourier transformation from a matrix of Fourier rows, each Fourier row being calculated from at least one of said time-sequential measurement signals as a projection of the nuclear spins on a frequency axis caused by the plurality of magnetic field gradients in said slice; (c) third means for generating a motion signal representative of said physical motion of said portion of the test object; (d) fourth means, coupled to said second means, for counting Fourier rows; and (e) fifth means, responsive to said fourth means and coupled to said second and third means, for controlling the calculation of said image such that said time-sequential measurement signals are continuously produced for use by said second means for the calculation of Fourier rows outside a predetermined region of the rows in said matrix, but are intermittently produced for use by said second means as a function of said motion signal when within said region.