Determination of a phase difference map
First Claim
1. A method for creating a phase difference map for generating image data of two different chemical substance types in a defined region of an examination object by way of magnetic resonance imaging measurement, the method comprising:
- respectively capturing first and second magnetic resonance raw echo data of the defined region at two different respective echo times;
reconstructing first and second image data of the defined region on the basis of the first and second magnetic resonance raw echo data;
determining candidate phase difference values on the basis of the first and second image data for image points of the defined region using a signal model of at least one of the two chemical substance types, the signal model containing a settable echo time parameter;
determining a linear portion of a spatial variation of the candidate phase difference values of image points for at least one subregion of the defined region;
performing a correction of the candidate phase difference values based on the linear portions; and
creating a phase difference map, with a phase difference value first being determined for a seed image point and then a phase difference value being selected, in each instance, from the corrected phase difference values of the respective image point starting from the seed image point in an image point by image point progressive growth method for further individual image points.
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Abstract
A method is described for determining a phase difference map for generating image data of two different chemical substance types in a defined region of an examination object via magnetic resonance imaging measurement. First and second magnetic resonance raw echo data of the defined region is first captured at two different arbitrary echo times. First and second image data of the defined region is then reconstructed on the basis of the first and second magnetic resonance raw echo data. Candidate phase difference values are finally determined on the basis of the first and second image data for image points of the defined region using a signal model of at least one of the two chemical substance types and the phase difference map is thus created. Also described are an image processing facility and a magnetic resonance unit including the image processing facility.
16 Citations
22 Claims
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1. A method for creating a phase difference map for generating image data of two different chemical substance types in a defined region of an examination object by way of magnetic resonance imaging measurement, the method comprising:
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respectively capturing first and second magnetic resonance raw echo data of the defined region at two different respective echo times; reconstructing first and second image data of the defined region on the basis of the first and second magnetic resonance raw echo data; determining candidate phase difference values on the basis of the first and second image data for image points of the defined region using a signal model of at least one of the two chemical substance types, the signal model containing a settable echo time parameter; determining a linear portion of a spatial variation of the candidate phase difference values of image points for at least one subregion of the defined region; performing a correction of the candidate phase difference values based on the linear portions; and creating a phase difference map, with a phase difference value first being determined for a seed image point and then a phase difference value being selected, in each instance, from the corrected phase difference values of the respective image point starting from the seed image point in an image point by image point progressive growth method for further individual image points. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. An image processing facility for determining a phase difference map, the image processing facility comprising:
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an interface, configured to respectively capture first and second magnetic resonance raw echo data of the defined region, the first and second magnetic resonance raw echo data being determined at two respectively different echo times; an image data reconstruction unit, configured to reconstruct first and second image data of the defined region on the basis of the respective first and second magnetic resonance raw echo data; and a phase difference determination unit, configured to determine candidate phase difference value on the basis of the first and second image data for image points of the defined region using a signal model of at least one of the two chemical substance types containing a settable echo time parameter, determine a linear portion of a spatial variation of the candidate phase difference values of image points for at least one subregion of the defined region, perform a correction of the candidate phase difference values based on the linear portion, and create a phase difference map, with a phase difference value first being determined for a seed image point and then a phase difference value being selected, in each instance, from the corrected phase difference values of the respective image point starting from the seed image point in an image point by image point progressive growth method for further individual image points. - View Dependent Claims (20, 21, 22)
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Specification