Thanks, Bruce, Doug,
I will check how to do that.
Hemant
Hi Hemant, sorry for the delay in getting back to you. I'm not sure what could be causing the problem. FreeSurfer definitely reads the direction cosines from the dicom. If you upload the dicom volume to our file drop, I'll take a look. filedrop url is at the end of this email.
doug
Hemant Bokil wrote:
Hi Bruce,
Thanks very much for your prompt reply. I am puzzled that freesurfer doesn't get the direction cosines. Which fields is it looking for in the dicom metadata ? When I load the slices in Matlab, I can see ImagePositionPatient and ImageOrientationPatient and SliceLocation and they all seem reasonable. Oddly this problem occurs on some datasets and not others even though I can't spot obvious differences in the dicom metadata fields.
As for your question regarding data origin, the problematic datasets are straight from the scanners as far as I know (although they were acquired from various hospitals as part of a long-done clinical study, so who knows..).
Hemant
------------------------------------------------------------------------On Fri, Feb 10, 2012 at 4:12 PM, Bruce Fischl <fischl@nmr.mgh.harvard.edu <mailto:fischl@nmr.mgh.harvard.edu>> wrote:
Hi Hemant
sorry for missing your previous post. I'm not sure what to tell
you though, if the direction cosines are nans that's going to be
trouble. You could still visualize your data in a slice viewer,
but you may never be able to tell left from right. Where did you
get the dicoms? Are they right off the scanner, or did they go
through some other package first? I don't think we've seen this
problem before.
cheers
Bruce
On Fri, 10 Feb 2012, Hemant Bokil wrote:
Hello,
I had posted this question earlier but no one picked it up so
I am trying
again. Briefly, I have been having difficulties with the very
first step of
the recon-all pipeline, namely, in conversion of my dicom
datasets to
freesurfer's mgz format. The error message (attached below)
suggests that
freesurfer is able to find the files correctly, but is unable
to find the
slice direction because it gets 'nan' for the variable Vs.
This seems to
result is problems with reslicing and program exits with
errors. Has anyone
encountered this issue ? The MR files themselves look fine
when viewed in
other viewers (note that this problem has now occurred with
several
different datasets). Would appreciate any input. Thanks,
Hemant
recon-all -s 101 -i DICOM_MR_DATA/101/1000430544_
ST3445_SR10_V10000.DICOM
Subject Stamp: freesurfer-Linux-centos4_x86_ 64-stable-pub-v5.1.0
Current Stamp: freesurfer-Linux-centos4_x86_ 64-stable-pub-v5.1.0
INFO: SUBJECTS_DIR is /home/hemant/ FreeSurferSubjects
Actual FREESURFER_HOME /usr/local/freesurfer
Linux Lab-3.intelect.local 2.6.32-71.29.1.el6.x86_64 #1 SMP
Mon Jun 27
19:49:27 BST 2011 x86_64 x86_64 x86_64 GNU/Linux
/home/hemant/ FreeSurferSubjects/101
mri_convert
/home/hemant/DICOM_MR_DATA/ 101/1000430544_ST3445_SR10_
V10000.DICOM
/home/hemant/ FreeSurferSubjects/101/mri/ orig/001.mgz
mri_convert
/home/hemant/DICOM_MR_DATA/ 101/1000430544_ST3445_SR10_
V10000.DICOM
/home/hemant/ FreeSurferSubjects/101/mri/ orig/001.mgz
$Id: mri_convert.c,v 1.179.2.2 2011/05/16 20:53:47 greve Exp $
reading from
/home/hemant/DICOM_MR_DATA/ 101/1000430544_ST3445_SR10_
V10000.DICOM...
Starting DICOMRead2()
dcmfile = /home/hemant/DICOM_MR_DATA/
101/1000430544_ST3445_SR10_ V10000.DICOM
dcmdir = /home/hemant/DICOM_MR_DATA/101
Ref Series No = 10
Found 139 files, checking for dicoms
Found 136 dicom files in series.
First Sorting
Computing Slice Direction
Vs: 0 0 0
Vs: -nan -nan -nan
Second Sorting
Counting frames
nframes = 136
nslices = 1
ndcmfiles = 136
PE Dir = ROW (dicom read)
TransferSyntaxUID: --1.2.840.10008.1.2--
jpegUID: --1.2.840.10008.1.2.4--
Loading pixel data
MRIresample(): error inverting matrix; determinant is -nan,
matrix is:
TR=5.25, TE=2.00, TI=450.00, flip angle=12.00
i_ras = (-1, 0, 0)
j_ras = (0, -1, 0)
k_ras = (nan, nan, -nan)
Reslicing using trilinear interpolation
-0.938 0.000 nan nan;
0.000 -0.938 nan nan;
0.000 0.000 -nan -nan;
0.000 0.000 0.000 1.000;
Linux Lab-3.intelect.local 2.6.32-71.29.1.el6.x86_64 #1 SMP
Mon Jun 27
19:49:27 BST 2011 x86_64 x86_64 x86_64 GNU/Linux
recon-all -s 101 exited with ERRORS at Fri Feb 10 16:00:03 EST
2012
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