Adaptive NMR angiographic reprojection method
First Claim
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1. A method for producing a magnetic resonance angiogram, the steps comprising:
- acquiring a 3D NMR data set comprised of a set of values which indicates by their magnitude the translational movement of spins and which indicates by their location in the 3D NMR data set the physical location of said spins;
producing a binary mask having a set of binary values in which there is a binary value corresponding to each value in the 3D NMR data set and the binary values are determined by a) locating regions in the 3D NMR data set in which the magnitude of its values exceed a first threshold value, b) enlarging those regions and c) setting the binary values in the binary mask which correspond to said enlarged regions to one of their binary values;
combining the 3D NMR data set with the binary mask to produce a 3D adapted data set in which values in the 3D NMR data set which correspond to binary values in the binary mask located outside the enlarged regions are removed from the 3D NMR data set; and
producing a 2D magnetic resonance angiogram from the 3D adapted data set in which a brightness value of each pixel in the 2D magnetic resonance angiogram is determined by the sum of all the data points therein that are disposed along the pixel'"'"'s projection ray.
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Abstract
A magnetic resonance angiogram is produced by projecting a 3D array of motion sensitized NMR data. A mask which locates the vessels in the 3D array is produced by thresholding the NMR data, and this mask is combined with the 3D NMR data set to exclude signals produced by surrounding stationary tissues. An integration projection technique is used to produce the angiogram from the masked data set.
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Citations
9 Claims
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1. A method for producing a magnetic resonance angiogram, the steps comprising:
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acquiring a 3D NMR data set comprised of a set of values which indicates by their magnitude the translational movement of spins and which indicates by their location in the 3D NMR data set the physical location of said spins; producing a binary mask having a set of binary values in which there is a binary value corresponding to each value in the 3D NMR data set and the binary values are determined by a) locating regions in the 3D NMR data set in which the magnitude of its values exceed a first threshold value, b) enlarging those regions and c) setting the binary values in the binary mask which correspond to said enlarged regions to one of their binary values; combining the 3D NMR data set with the binary mask to produce a 3D adapted data set in which values in the 3D NMR data set which correspond to binary values in the binary mask located outside the enlarged regions are removed from the 3D NMR data set; and producing a 2D magnetic resonance angiogram from the 3D adapted data set in which a brightness value of each pixel in the 2D magnetic resonance angiogram is determined by the sum of all the data points therein that are disposed along the pixel'"'"'s projection ray. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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Specification