System and method for background phase correction for phase contrast flow images
AssigneeSiemens Aktiengesellschaft
InventorsJens Gühring, Marie-Pierre Jolly, Hui Xue
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Abstract
A method for correcting the background phase in magnetic resonance phase contrast flow images includes providing a time series of velocity encoded magnetic resonance images of a patient, where the time series of velocity encoded images comprises for each time point a phase contrast image where a pixel intensity is proportional to a flow velocity, measuring a change of intensity for each pixel over the time series of phase contrast images, identifying pixels with a low measure of temporal change as stationary pixels, and calculating a correction field for the stationary pixels, where the correction field represents a background phase to be subtracted from the phase contrast image.
Claims16
A method for correcting the background phase in magnetic resonance phase contrast flow images, the method comprising the steps of:
- providing a time series of anatomical magnetic resonance images and velocity encoded magnetic resonance images of a patient, wherein said time series of velocity encoded images comprises for each time point a phase contrast image wherein a pixel intensity is proportional to a flow velocity;
- computing, for each pixel, an intensity variance over the time series of phase contrast images and an intensity variance over the time series of anatomical images;
- selecting, for each pixel, the maximum of the intensity variance over the phase contrast images and the intensity variance over the anatomical images as a measure of temporal variance for each pixel;
- forming a histogram of the intensity variance of all pixels;
- determining a threshold from said histogram, wherein pixels whose intensity change is less than the threshold are considered as stationary pixels, and pixels whose intensity change is greater than the threshold are considered as moving pixels;
- and
- calculating a correction field for the stationary pixels, wherein said correction field represents a background phase to be subtracted from the phase contrast image.
A non-transitory computer readable program storage device, embodying a program of instructions executable by a computer to perform method steps for correcting the background phase in magnetic resonance phase contrast flow images, the method comprising the steps of:
- providing a time series of anatomical magnetic resonance images and velocity encoded magnetic resonance images of a patient, wherein said time series of velocity encoded images comprises for each time point a phase contrast image wherein a pixel intensity is proportional to a flow velocity;
- computing, for each pixel, an intensity variance over the time series of phase contrast images and an intensity variance over the time series of anatomical images;
- selecting, for each pixel, the maximum of the intensity change over the phase contrast images and the intensity change over the anatomical images as the measure of temporal change for each pixel;
- forming a histogram of the intensity variance of all pixels;
- determining a threshold from said histogram, wherein pixels whose intensity change is less than the threshold are considered as stationary pixels, and pixels whose intensity change is greater than the threshold are considered as moving pixels;
- and
- calculating a correction field for the stationary pixels, wherein said correction field represents a background phase to be subtracted from the phase contrast image.
Dependencies are inferred from the claim text.