p.s. are the 001.mgz and 002.mgz dark? The orig.mgz? Sometimes nu_correct can create very dark images, and there are some switches you can loo through to correct them. Alternatively if it is the 001.mgz, mri_convert has a scale option you can use.

cheers,
Bruce


On Fri, 25 Apr 2008, Jerry Yeou-Wei Chen wrote:

Okay, thanks for your help again Nick!
Regarding the scan data: I am actually working with data collected by a
previous member of our lab, and there were indeed some problems... (related
to the SCIC algorithm on our GE scanner). So, our technician created a
program to "uncorrect" the intensity scaling.  The images he saved appear
dark when we load them freesurfer, but we expected autorecon's intensity
normalization would handle this. In fact, autorecon did successfully process
34 out of 35 scans. (the cortical surface appears quite decent for them, and
the thickness values on our average subject appears to be within normal
range...)
I wonder if I should be concerned about our results due to this intensity
issue...

On Tue, Apr 22, 2008 at 2:42 PM, Nick Schmansky <[EMAIL PROTECTED]>
wrote:

Jerry,

At this point, I think Bruce will need to jump-in to answer (he is out-
of-town today).  I think he will ask about your scan parameters, ie, how
is your scanner setup?  It sounds as if something is not quite right in
the data coming-off the scanner.

Nick


On Tue, 2008-04-22 at 14:26 -0400, Jerry Yeou-Wei Chen wrote:
Thanks for the reply, Nick. I think you correctly identified the
problem.
nu.mgz is oriented correctly, but looks very dark... However, it looks
decent if I adjust the brightness/contrast....
I have other scans that were processed without error, and the
orig.mgz, and nu.mgz also appear quite dark (and the mri peaks are
very low, too: 29, 46, 52, ...) Also, for those successfully
processed, the brainmask.mgz looks decent as well.
Perhaps this scan that exited with error was too dark to be corrected
by the intensity normalization algorithm?

- Jerry

On Tue, Apr 22, 2008 at 1:22 PM, Nick Schmansky
<[EMAIL PROTECTED]> wrote:
        Jerry,

        I'm not sure why it exited without giving a better message,
        but this is
        a clue why it exited:


        before smoothing, mri peak at 0
        after smoothing, mri peak at 0, scaling input intensities by
        inf




        the mri peak is at zero, which is wrong (it should be around
        116/117 or
        so).

        if you view nu.mgz (tkmedit -f nu.mgz), does it look ok?  is
        it oriented
        correctly?

        Nick





        On Tue, 2008-04-22 at 12:28 -0400, Jerry Yeou-Wei Chen wrote:
       > Hello,
       >
       > I am having trouble deciphering why I got the error attached
        below.
       > Any suggestions would be greatly appreciated!
       >
       > Thanks,
       > - Jerry
       >
       >
       >
       >
       > Tue Apr 22 10:15:22 EDT 2008
       > talairach_avi done
       >
       >  cp transforms/talairach.auto.xfm transforms/talairach.xfm
       >
       > #--------------------------------------------
       > [EMAIL PROTECTED] Talairach Failure Detection Tue Apr 22 10:15:23 EDT 
2008
       > /scratch/freesurfer/subjects/17/s017/mri
       >
       >  talairach_afd -T 0.005 -xfm transforms/talairach.xfm
       >
       > talairach_afd: Talairach Transform: transforms/talairach.xfm
        OK
       > (p=0.7072, pval=0.4932 >= threshold=0.0050)
       >
       >  awk -
       >
        f /scratch/freesurfer/bin/extract_talairach_avi_QA.awk
/scratch/freesurfer/subjects/17/s017/mri/transforms/talairach_avi.log
       >
       > TalAviQA: 0.96840
       > z-score: -2
       > #--------------------------------------------
       > [EMAIL PROTECTED] Intensity Normalization Tue Apr 22 10:15:23 EDT 2008
       > /scratch/freesurfer/subjects/17/s017/mri
       >
       >  mri_normalize -g 1 nu.mgz T1.mgz
       >
       > using max gradient = 1.000
       > reading from nu.mgz...
       > normalizing image...
       > talairach transform
       >  0.976   0.083   0.030  -136.866;
       > -0.072   1.053   0.164  -153.262;
       > -0.020  -0.109   1.085  -122.101;
       >  0.000   0.000   0.000   1.000;
       > INFO: Modifying talairach volume c_(r,a,s) based on
        average_305
       > building Voronoi diagram...
       > performing soap bubble smoothing...
       > 3d normalization pass 1 of 2
       > building Voronoi diagram...
       > performing soap bubble smoothing...
       > 3d normalization pass 2 of 2
       > building Voronoi diagram...
       > performing soap bubble smoothing...
       > writing output to T1.mgz
       > 3D bias adjustment took 19 minutes and 44 seconds.
       > white matter peak found at 111
       > gm peak at 88 (88), valley at 80 (80)
       > csf peak at 57, setting threshold to 77
       > white matter peak found at 111
       > gm peak at 88 (88), valley at 80 (80)
       > csf peak at 55, setting threshold to 77
       > #--------------------------------------------
       > [EMAIL PROTECTED] Skull Stripping Tue Apr 22 10:35:16 EDT 2008
       > /scratch/freesurfer/subjects/17/s017/mri
       >
       >  mri_em_register -skull
       >
        nu.mgz
/scratch/freesurfer/average/RB_all_withskull_2008-03-26.gca
       > transforms/talairach_with_skull.lta
       >
       > aligning to atlas containing skull, setting
        unknown_nbr_spacing = 5
       > reading 1 input volumes...
       > logging results to talairach_with_skull.log
       > reading
       >
        '/scratch/freesurfer/average/RB_all_withskull_2008-03-26.gca'...
       > average std = 23.1   using min determinant for
        regularization = 53.4
       > 0 singular and 5702 ill-conditioned covariance matrices
        regularized
       > reading 'nu.mgz'...
       > freeing gibbs priors...done.
       > bounding unknown intensity as < 20.2 or > 943.7
       > total sample mean = 92.0 (1443 zeros)
       > ************************************************
       > spacing=8, using 3481 sample points, tol=1.00e-05...
       > ************************************************
       > register_mri: find_optimal_transform
       > find_optimal_transform: nsamples 3481, passno 0, spacing 8
       > GCAhistoScaleImageIntensities: could not find wm peak
       > resetting wm mean[0]: 117 --> 126
       > resetting gm mean[0]: 74 --> 74
       > input volume #1 is the most T1-like
       > using real data threshold=9.0
       > using (102, 110, 122) as brain centroid...
       > mean wm in atlas = 126, using box (80,83,98) --> (123,
        136,146) to
       > find MRI wm
       > before smoothing, mri peak at 0
       > after smoothing, mri peak at 0, scaling input intensities by
        inf
       > Linux kdavis8-efef.uhnres.utoronto.ca 2.6.23.1-21.fc7 #1 SMP
        Thu Nov 1
       > 21:09:24 EDT 2007 i686 i686 i386 GNU/Linux
       >
       > recon-all exited with ERRORS at Tue Apr 22 10:41:40 EDT 2008

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