Correction of saturation banding artifacts in magnetic resonance imaging
Systems and methods for correcting saturation banding artifacts in magnetic resonance imaging in which artifact and reference calibration scans are used to create one dimensional or two dimensional correction profiles, which are subsequently applied to actual diagnostic imaging scans to correct the saturation banding artifacts.
1. A method for correcting saturation banding in magnetic resonance imaging comprising:
acquiring at least one artifact calibration scan, with a timing that corresponds to that of an actual diagnostic imaging scan;
acquiring at least one reference calibration scan, with a timing that corresponds to that of the actual diagnostic imaging scan;
determining a mask of saturation bands in the at least one artifact calibration scan;
dividing each voxel in the at least one reference calibration scan by each corresponding voxel in the at least one artifact calibration scan within the extent of the mask to determine mask region correction values;
assigning the mask region correction values to corresponding voxels in a two dimensional signal correction profile, the corresponding voxels being within the extent of the mask, and
assigning a preselected constant value to a plurality of voxels in the two dimensional signal correction profile, the plurality of voxels being outside of the extent of the mask;
applying the two dimensional signal correction profile to the actual diagnostic imaging scan.
2. The method of claim 1 , wherein applying the two dimensional signal correction profile comprises
multiplying each of the voxels in the actual diagnostic imaging scan by a corresponding value in the two dimensional signal correction profile to obtain a corrected diagnostic image.
3. The method of claim 1 , wherein determining the mask of saturation bands includes using a segmentation algorithm on the at least one artifact calibration scan.
4. The method of claim 1 , wherein determining the mask of saturation bands includes determining locations of saturation bands using information on the physical locations of the acquired slices and using a band thickness of at least the thickness of a slice.
5. The method of claim 4 , wherein the band thickness is at least 4 times the slice thickness.
6. The method of claim 1 , wherein a plurality of artifact calibration scans and a plurality of reference calibration scans are acquired and wherein dividing each voxel in the at least one reference calibration scan by each corresponding voxel in the at least one artifact calibration scan comprises dividing an average of the voxels in the plurality of artifact calibration scans by an average of the corresponding voxels in the plurality of reference calibration scans.
7. The method of claim 1 , further comprising normalizing the at least one artifact calibration scan with a mean intensity of the at least one artifact calibration scan and normalizing the at least one reference calibration scan with a mean intensity of the at least one reference calibration scan.
8. The method of claim 1 , wherein the preselected constant value is substantially equal to one.
9. The method of claim 2 , wherein the acquiring at least one artifact calibration scan and the acquiring at least one reference calibration scan are performed by an MRI scanner and wherein the corrected diagnostic image is output to a display.
10. A method for correcting saturation banding in magnetic resonance imaging comprising:
acquiring at least one artifact calibration scan, with a timing that corresponds to that of an actual diagnostic imaging scan;
acquiring at least one reference calibration scan, with a timing that corresponds to that of the actual diagnostic imaging scan;
determining a mask of saturation bands in the at least one artifact calibration scan;
dividing each voxel in the at least one reference calibration scan by each corresponding voxel in the at least one artifact calibration scan within the extent of the mask to determine mask region correction values;
assigning the mask region correction values to corresponding voxels in a two dimensional signal correction profile, the corresponding voxels being within the extent of the mask, and
applying the two dimensional signal correction profile to the actual diagnostic imaging scan.
11. The method of claim 10 , wherein applying the two dimensional signal correction profile comprises multiplying each of the voxels in a mask region of the actual diagnostic imaging scan by a corresponding value in the two dimensional signal correction profile to obtain a corrected diagnostic image.
12. The method of claim 11 , wherein the acquiring at least one artifact calibration scan and the acquiring at least one reference calibration scan are performed by an MRI scanner and wherein the corrected diagnostic image is output to a display.
13. A method for correcting saturation banding in magnetic resonance imaging comprising:
acquiring a plurality of artifact calibration scans, with a timing that corresponds to that of an actual diagnostic imaging scan, the plurality of artifact calibration scans each comprising a plurality voxels;
acquiring a plurality of reference calibration scans, with a timing that corresponds to that of the actual diagnostic imaging scan, the plurality of reference calibration scans each comprising a plurality of voxels;
creating an average artifact calibration scan by averaging the value of each voxel across the plurality of artifact calibration scans;
creating an average reference calibration scan by averaging the value of each voxel across the plurality of reference calibration scans;
dividing each voxel of the average reference calibration scan by each corresponding voxel of the average artifact calibration scan to create a two dimensional signal correction profile; and
applying the two dimensional signal correction profile to the actual diagnostic imaging scan.
14. The method of claim 13 , wherein applying the two dimension signal correction profile comprises
multiplying each of the voxels in the actual diagnostic imaging scan by a corresponding value in the two dimensional signal correction profile to obtain a corrected diagnostic image.
15. The method of claim 14 , wherein the acquiring a plurality of artifact calibration scans and the acquiring a plurality of reference calibration scans are performed by an MRI scanner and wherein the corrected diagnostic image is output to a display.