Dear all, For a structural study, I would like to determine cortical T1 values. T1 map generation from two FLASH images works like a charm, and I would like to add B1 correction now. I have acquired flip angle maps for my subjects (using the Yarnykh method with interleaved FLASH and two TRs), and would like to correct my T1 maps accordingly. Looking at the online help of mri_ms_fitparms, I think the parameter -afi should do the trick. However, I'm not sure about the properties of the flip angle map that I need to supply to mri_ms_fitparms. Does that programme expect absolute flip angle values? Or can I feed in my two AFI FLASH volumes in some way? If anyone can point me in the right direction, that would be great! Thanks for you help, Johannes
Hi Johannes
you should give it a flip angle map in degrees. We assume that the nominal flip angle (that is, if B1 was homogeneous) would be 60 deg.
cheers Bruce
On Mon, 21 Nov 2011, Dr.med. Johannes C. Klein wrote:
Dear all, For a structural study, I would like to determine cortical T1 values. T1 map generation from two FLASH images works like a charm, and I would like to add B1 correction now. I have acquired flip angle maps for my subjects (using the Yarnykh method with interleaved FLASH and two TRs), and would like to correct my T1 maps accordingly. Looking at the online help of mri_ms_fitparms, I think the parameter -afi should do the trick. However, I'm not sure about the properties of the flip angle map that I need to supply to mri_ms_fitparms. Does that programme expect absolute flip angle values? Or can I feed in my two AFI FLASH volumes in some way? If anyone can point me in the right direction, that would be great! Thanks for you help, Johannes _______________________________________________ Freesurfer mailing list Freesurfer@nmr.mgh.harvard.edu https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer
Hi Bruce, Thanks a lot for your (very speedy) help! Cheers, Johannes
Am 21 Nov 2011 um 18:21 schrieb Bruce Fischl:
Hi Johannes
you should give it a flip angle map in degrees. We assume that the nominal flip angle (that is, if B1 was homogeneous) would be 60 deg.
cheers Bruce
On Mon, 21 Nov 2011, Dr.med. Johannes C. Klein wrote:
Dear all, For a structural study, I would like to determine cortical T1 values. T1 map generation from two FLASH images works like a charm, and I would like to add B1 correction now. I have acquired flip angle maps for my subjects (using the Yarnykh method with interleaved FLASH and two TRs), and would like to correct my T1 maps accordingly. Looking at the online help of mri_ms_fitparms, I think the parameter -afi should do the trick. However, I'm not sure about the properties of the flip angle map that I need to supply to mri_ms_fitparms. Does that programme expect absolute flip angle values? Or can I feed in my two AFI FLASH volumes in some way? If anyone can point me in the right direction, that would be great! Thanks for you help, Johannes _______________________________________________ Freesurfer mailing list Freesurfer@nmr.mgh.harvard.edu https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer
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sure On Mon, 21 Nov 2011, Dr.med. Johannes C. Klein wrote:
Hi Bruce, Thanks a lot for your (very speedy) help! Cheers, Johannes
Am 21 Nov 2011 um 18:21 schrieb Bruce Fischl:
Hi Johannes
you should give it a flip angle map in degrees. We assume that the nominal flip angle (that is, if B1 was homogeneous) would be 60 deg.
cheers Bruce
On Mon, 21 Nov 2011, Dr.med. Johannes C. Klein wrote:
Dear all, For a structural study, I would like to determine cortical T1 values. T1 map generation from two FLASH images works like a charm, and I would like to add B1 correction now. I have acquired flip angle maps for my subjects (using the Yarnykh method with interleaved FLASH and two TRs), and would like to correct my T1 maps accordingly. Looking at the online help of mri_ms_fitparms, I think the parameter -afi should do the trick. However, I'm not sure about the properties of the flip angle map that I need to supply to mri_ms_fitparms. Does that programme expect absolute flip angle values? Or can I feed in my two AFI FLASH volumes in some way? If anyone can point me in the right direction, that would be great! Thanks for you help, Johannes _______________________________________________ Freesurfer mailing list Freesurfer@nmr.mgh.harvard.edu https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer
The information in this e-mail is intended only for the person to whom it is addressed. If you believe this e-mail was sent to you in error and the e-mail contains patient information, please contact the Partners Compliance HelpLine at http://www.partners.org/complianceline . If the e-mail was sent to you in error but does not contain patient information, please contact the sender and properly dispose of the e-mail.
freesurfer@nmr.mgh.harvard.edu
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Bruce Fischl -
Dr.med. Johannes C. Klein