you could get a T2 or FLAIR and use it to fix the pial surface On Fri, 1 Aug 2014, McLaughlin, Katie wrote:
> Hi Andre and Bruce, > > Thanks for your input here. The sat band has helped, although it hasn't > entirely corrected the problem (the image attached was from a subject with > the sat bands included). We are using a local transmit coil. > > I'm going to check with our physicist about the inversion pulse - thanks for > the suggestion. > > Any other thoughts about strategies for improving this are welcome! Andre, > would you mind sharing how you segmented the blood vessels and labeled in > FreeSurfer? We could try that approach... > > Thanks, > Kate > > ________________________________________ > From: [email protected] > [[email protected]] on behalf of Andre van der Kouwe > [[email protected]] > Sent: Friday, August 01, 2014 1:00 PM > To: Bruce Fischl; Freesurfer support list > Cc: Dylan Tisdall > Subject: Re: [Freesurfer] High intensity blood vessels in children with > meMPRAGE > > Hi, > > Thanks, yes, we have this problem on our scans from the Allegra and 7 T > scanners, where there's a local transmit coil (no body transmit coil) > and therefore blood with non-inverted spins enters the head after the > inversion pulse and appears bright in the images. With our Allegra scans > this has indeed caused problems with FreeSurfer, where the vessels are > included as part of some labelled structures. I did try to segment and > label the vessels with only partial success (since the images are > already collected). In your case, a sat band might help... is your > inversion pulse non-selective? If you have an axial slab and axial > slab-selective inversion, maybe just making the inversion pulse > non-selective will help. If the coil has no coverage of the neck, I > guess your sat band won't work and you'll have to address the issue in > post-processing. Sorry, I don't have a specific solution, but we've also > seen the problem. First thing perhaps is to verify whether you're using > a local transmit coil. > > Cheers, > > Andre. > > On 08/01/2014 12:50 PM, Bruce Fischl wrote: >> Hi Kate >> >> I'll cc Andre and Dylan, but I would have thought some sat bands in the >> neck would do it. I think vessels are usually bright in the mprage, but >> don't usually case problems. Comments welcome.... >> >> cheers >> >> Bruce >> >> On Fri, 1 Aug 2014, McLaughlin, Katie wrote: >> >>> >>> Hi Doug, Bruce, et al. >>> We've used the MGH meMPRAGE protocol successfully with children and >>> adolescents previously on a Siemens 3T. I've recently moved to a new >>> institution and am using the protocol on a Philips 3T Achieva scanner and >>> we've been having a lot of issues with high-intensity blood vessels >>> (appearing bright white and interfering with segmentation in FreeSurfer). >>> Screenshot of an example attached. >>> >>> We have added some rest slabs/sat bands to the protocol to address >>> this, but >>> it hasn't fully solved the problem. >>> >>> I'm wondering if you have any recommendations about adjusting things in >>> FreeSurfer to help us get better segmentation? >>> >>> Thanks for your thoughts on this, >>> Kate >>> >>> >>> >>> > _______________________________________________ > Freesurfer mailing list > [email protected] > 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 mailing list [email protected] https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer
