System for Dynamically Compensating for Inhomogeneity in an MR Imaging Device Magnetic Field

摘要

A system automatically dynamically compensates for inhomogeneity in an MR imaging device magnetic field. An MR imaging compensation system applies swept frequency magnetic field variation in determining an estimate of proton spin frequency at multiple individual locations associated with individual image elements in an anatomical volume of interest and substantially independently of tissue associated relaxation time. For the multiple individual locations, the system determines an offset frequency comprising a difference between a determined estimate of proton spin frequency associated with an individual image element location and a nominal proton spin frequency. The system derives data representing an electrical signal to be applied to magnetic field generation coils to substantially compensate for determined offset frequencies at the multiple individual locations. An MR magnetic field coil generates a magnetic field in response to applying the electrical signal to substantially compensate for magnetic field variation represented by the determined offset frequencies at the multiple individual locations.