Hi, 3D SPGR sequences were used. (TR=22, TE=4, thickness=1.4, FOV=240*240, FA=40) If the artifacts are due to B0 distortion, I wonder how I can fix it.
Thanks, Youngmin Huh
2012/11/12 Bruce Fischl fischl@nmr.mgh.harvard.edu
Can you give us the acquisition details? I suspect this is not noise, but rather B0 distortion. what is the acquisition? And what bandwidth?
On Nov 8, 2012, at 2:53 AM, youngmin huh ymin1123@gmail.com wrote:
Dear all,
I'm working with some images, and they have so much noises on temporal
areas.
I just ran recon2, but not sure if they'll be segmented properly. Does anyone have a recommendation for dealing with it? I wonder if there is any flag or option for this occasion. I would appreciate any comments or help. I attached an example.
Thanks,
Youngmin Huh <temporal_001.jpg>
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Are you using a 32-channel coil? It looks like B1- receive field inhomogeneity to me.
Peace,
Matt.
From: youngmin huh ymin1123@gmail.com Date: Monday, November 12, 2012 10:22 PM To: Bruce Fischl fischl@nmr.mgh.harvard.edu, freesurfer@nmr.mgh.harvard.edu Subject: Re: [Freesurfer] bad acquisition and noise problem.
Hi, 3D SPGR sequences were used. (TR=22, TE=4, thickness=1.4, FOV=240*240, FA=40) If the artifacts are due to B0 distortion, I wonder how I can fix it.
Thanks, Youngmin Huh
2012/11/12 Bruce Fischl fischl@nmr.mgh.harvard.edu
Can you give us the acquisition details? I suspect this is not noise, but rather B0 distortion. what is the acquisition? And what bandwidth?
On Nov 8, 2012, at 2:53 AM, youngmin huh ymin1123@gmail.com wrote:
Dear all,
I'm working with some images, and they have so much noises on temporal
areas.
I just ran recon2, but not sure if they'll be segmented properly. Does anyone have a recommendation for dealing with it? I wonder if there is any flag or option for this occasion. I would appreciate any comments or help. I attached an example.
Thanks,
Youngmin Huh <temporal_001.jpg>
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 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.
what is the bandwidth? The typical way to fix it is to increase the bandwidth. You can probably recover some of the SNR you will lose by reducing your flip angle, which is pretty far from the Ernst angle. Also, minimize your TE (if 4ms is not already the min) cheers Bruce
On Tue, 13 Nov 2012, youngmin huh wrote:
Hi, 3D SPGR sequences were used. (TR=22, TE=4, thickness=1.4, FOV=240*240, FA=40) If the artifacts are due to B0 distortion, I wonder how I can fix it.
Thanks, Youngmin Huh
2012/11/12 Bruce Fischl fischl@nmr.mgh.harvard.edu Can you give us the acquisition details? I suspect this is not noise, but rather B0 distortion. what is the acquisition? And what bandwidth?
On Nov 8, 2012, at 2:53 AM, youngmin huh <ymin1123@gmail.com> wrote: > Dear all, > > I'm working with some images, and they have so much noises on temporal areas. > I just ran recon2, but not sure if they'll be segmented properly. > Does anyone have a recommendation for dealing with it? > I wonder if there is any flag or option for this occasion. > I would appreciate any comments or help. > I attached an example. > > Thanks, > > Youngmin Huh<temporal_001.jpg>
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.
I'm not engaged in obtaining images, so I don't have any details about the images. I wonder the method which you commented can be applied to images I already earned. If it's not, is there any way to recover SNR after image scanning?
Thanks,
Youngmin Huh.
2012/11/13 Bruce Fischl fischl@nmr.mgh.harvard.edu
what is the bandwidth? The typical way to fix it is to increase the bandwidth. You can probably recover some of the SNR you will lose by reducing your flip angle, which is pretty far from the Ernst angle. Also, minimize your TE (if 4ms is not already the min) cheers Bruce
On Tue, 13 Nov 2012, youngmin huh wrote:
Hi,
3D SPGR sequences were used. (TR=22, TE=4, thickness=1.4, FOV=240*240, FA=40) If the artifacts are due to B0 distortion, I wonder how I can fix it.
Thanks, Youngmin Huh
2012/11/12 Bruce Fischl fischl@nmr.mgh.harvard.edu Can you give us the acquisition details? I suspect this is not noise, but rather B0 distortion. what is the acquisition? And what bandwidth?
On Nov 8, 2012, at 2:53 AM, youngmin huh <ymin1123@gmail.com> wrote: > Dear all, > > I'm working with some images, and they have so much noises on temporal areas. > I just ran recon2, but not sure if they'll be segmented properly. > Does anyone have a recommendation for dealing with it? > I wonder if there is any flag or option for this occasion. > I would appreciate any comments or help. > I attached an example. > > Thanks, > > Youngmin Huh<temporal_001.jpg>
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/**compliancelinehttp://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.
it's not a question of SNR, the problem appears to me to be that the B0 distortions are so bad that a bunch of the temporal lobe is piled up on top of itself. There's no way to fix that posthoc. If you upload the full volume I'm happy to take a look
On Wed, 14 Nov 2012, youngmin huh wrote:
I'm not engaged in obtaining images, so I don't have any details about the images.I wonder the method which you commented can be applied to images I already earned. If it's not, is there any way to recover SNR after image scanning?
Thanks,
Youngmin Huh.
2012/11/13 Bruce Fischl fischl@nmr.mgh.harvard.edu what is the bandwidth? The typical way to fix it is to increase the bandwidth. You can probably recover some of the SNR you will lose by reducing your flip angle, which is pretty far from the Ernst angle. Also, minimize your TE (if 4ms is not already the min) cheers Bruce
On Tue, 13 Nov 2012, youngmin huh wrote: Hi, 3D SPGR sequences were used. (TR=22, TE=4, thickness=1.4, FOV=240*240, FA=40) If the artifacts are due to B0 distortion, I wonder how I can fix it. Thanks, Youngmin Huh 2012/11/12 Bruce Fischl <fischl@nmr.mgh.harvard.edu> Can you give us the acquisition details? I suspect this is not noise, but rather B0 distortion. what is the acquisition? And what bandwidth? On Nov 8, 2012, at 2:53 AM, youngmin huh <ymin1123@gmail.com> wrote: > Dear all, > > I'm working with some images, and they have so much noises on temporal areas. > I just ran recon2, but not sure if they'll be segmented properly. > Does anyone have a recommendation for dealing with it? > I wonder if there is any flag or option for this occasion. > I would appreciate any comments or help. > I attached an example. > > Thanks, > > Youngmin Huh > <temporal_001.jpg> 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 -
Matt Glasser -
youngmin huh