Difference between revisions of "B0 & B1 mitigation using time-shifted spokes"
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=== Instructions === | === Instructions === | ||
| − | ==== Fitting the through-slice B0 gradient map ==== | + | ==== Fitting the through-slice B0 gradient map / preparing the B1+ maps ==== |
| − | To perform this step, download and un-zip the file processPrescanData.zip. First, run the Matlab routine dump_g.m and then the routine dump_b1maps.m. For a detailed description of | + | To perform this step, download and un-zip the file processPrescanData.zip. First, run the Matlab routine dump_g.m and then the routine dump_b1maps.m. These tools prepare the B1+ maps in a format adequate for pulse design and estimate the B0 through-slice gradient by linear fit (in the slice direction) of two 3D GRE acquisitions with slightly different TEs. For a detailed description of these step, please refer to the paper in the Citation section. |
NOTE #1: These tools will only work for data acquired on Siemens scanners equipped with the "step 2" pTx system. For other systems you may have to adapt the code yourself. | NOTE #1: These tools will only work for data acquired on Siemens scanners equipped with the "step 2" pTx system. For other systems you may have to adapt the code yourself. | ||
NOTE #2: These tools assume that there are two meas*.dat files in the working folder containing the raw data of two GRE acquisitions with TE # 1 = 6 ms and TE # 2 = 8 ms. I did not include my own files because they are too big for this Wiki. These meas*.dat files can be saved after you have acquired the GRE data using the Twix scanner utility. The file fieldMaps.fld is the standard file generated when clicking "save dataset" in the B1+ application of the Siemens "step 2" pTx system. | NOTE #2: These tools assume that there are two meas*.dat files in the working folder containing the raw data of two GRE acquisitions with TE # 1 = 6 ms and TE # 2 = 8 ms. I did not include my own files because they are too big for this Wiki. These meas*.dat files can be saved after you have acquired the GRE data using the Twix scanner utility. The file fieldMaps.fld is the standard file generated when clicking "save dataset" in the B1+ application of the Siemens "step 2" pTx system. | ||
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Revision as of 18:00, 6 October 2015
Citation
Coming up soon
What this code does
Coming up soon
Download files
Click here to download the Matlab code and here for the test dataset. You'll also need to download this zip file with a few utilities and add the un-zipped folder to your Matlab path.
If you are wondering how exactly I obtained the B0 and through-slice B0 gradient maps, download this zip file.
Instructions
Fitting the through-slice B0 gradient map / preparing the B1+ maps
To perform this step, download and un-zip the file processPrescanData.zip. First, run the Matlab routine dump_g.m and then the routine dump_b1maps.m. These tools prepare the B1+ maps in a format adequate for pulse design and estimate the B0 through-slice gradient by linear fit (in the slice direction) of two 3D GRE acquisitions with slightly different TEs. For a detailed description of these step, please refer to the paper in the Citation section.
NOTE #1: These tools will only work for data acquired on Siemens scanners equipped with the "step 2" pTx system. For other systems you may have to adapt the code yourself.
NOTE #2: These tools assume that there are two meas*.dat files in the working folder containing the raw data of two GRE acquisitions with TE # 1 = 6 ms and TE # 2 = 8 ms. I did not include my own files because they are too big for this Wiki. These meas*.dat files can be saved after you have acquired the GRE data using the Twix scanner utility. The file fieldMaps.fld is the standard file generated when clicking "save dataset" in the B1+ application of the Siemens "step 2" pTx system.