Determining absolute image intensity in magnetic resonance systems
AssigneeElscint Ltd.
InventorSaul Stokar
Life of this patent
Estimating the term…
Abstract
A magnetic resonance (MR) system and method for determing absolute image intensities (MR numbers) comparable to "CT" numbers by removing the dependence of the intensity measurement on system dependent parameters. The dependence of the intensity measurement on system parameters is removed by determining the absolute gain of the receiver portion of the MR system. The absolute gain is a function of the loaded gain and the unloaded gain of the receiver system, the loaded gain is divided by the unloaded gain to provide a normalization factor which is multiplied by output data to provide the absolute values of intensity of absolute MR numbers.
Claims17
A magnetic resonance data acquisition system comprising:
- magnet means for generating a relatively large static magnetic field for aligning spins in a subject in said system,
- means for transmitting Rf pulses for nutating said aligned spins,
- receiver means for receiving Rf signals generated by the nutated spins of the subject in the magnet means and of a phantom separately in the magnet means in the same location as the subject as the nutated spins return to the aligned position after termination of the Rf pulses, said receiver means having an output providing said received Rf signals,
- means for adjusting the output of said receiver means to provide received Rf signals from said phantom which conform to the phantom proton density,
- means for processing said Rf signals received from said subject to provide relative MR numbers as a function of location but uncorrected to absolute proton density and for subject loading, and
- means for determining an absolute gain of the receiver means to obtain absolute MR numbers from the relative MR numbers, said absolute MR numbers being normalized to absolute proton density and subject loading.
A magnetic resonance (MR) data acquisition method for an MR system including Rf transmitting and receiving means, said method comprising the steps of:
- generating a relatively large static magnetic field for aligning spins in a subject in said system,
- transmitting Rf pulses for nutating said aligned spins,
- receiving Rf signals generated by the nutated spins as the nutated spins return to the aligned position after termination of the Rf pulses,
- processing said received Rf signals to provide relative MR numbers as a function of location, and
- determining an absolute gain of said receiver means to obtain absolute MR numbers from the relative MR numbers.
Dependencies are inferred from the claim text.