I'm just going to repeat the usual stuff here. Make sure that the images are
in reasonable alignment with MNI space before you begin. Have the AC within
about 2 to 3 cm of the 0,0,0 coordinate, and the orientation within about 15
degrees. The Check Reg and Display buttons are useful for doing this.
Best regards,
-John
On Monday 17 November 2008 09:57, KASMAI BAHMAN (RM1) Norfolk and Norwich
University Hospital wrote:
> Thank you for your reply. I left the machine on overnight and it had
> managed to complete the job in about two hours. However the results are
> rather bizarre (see attached). The SPM8b seems to have imported Dicom
> images correctly as it can in the attached file. Am I doing something
> silly? Could it be that the dataset are incorrect?
>
> Bahman
>
> Norfolk & Norwich University Hospital NHS Trust
> Cloney Lane, Norwich
> NR4 7UY, United Kingdon
> Tel: 01603 286178
> -----Original Message-----
> From: SPM (Statistical Parametric Mapping) [mailto:[log in to unmask]] On
> Behalf Of Kathy Pearson Sent: 14 November 2008 17:47
> To: [log in to unmask]
> Subject: Re: [SPM] SPM8b segmentation and structural volume size
>
> Bahman,
>
> It could depend on your combination of MATLAB version, OS, and hardware. I
> noticed a similar problem in SPM2/SPM5 for normalization and smoothing on
> 64-bit Linux with MATLAB 7.5, taking over an hour on my system. For me,
> the more files in a directory, the longer these steps take. The slow-down
> may be due in part to repeated references to the "exist" function before a
> new file is created. Reducing those "exists" calls helped me by a factor
> of 2 or 3, but what I finally had to do to make this go at a reasonable
> speed was to create a special directory to hold only the files to be worked
> on, smooth or normalize, then move them back to the original directory when
> processed -- done in just a few minutes. However, some other scheme may
> better suit your particular case.
>
> Kathy Pearson
> UAB Psychology
>
> ________________________________________
> From: SPM (Statistical Parametric Mapping) [mailto:[log in to unmask]] On
> Behalf Of KASMAI BAHMAN (RM1) Norfolk and Norwich University Hospital
> Sent: Friday, November 14, 2008 10:54 AM
> To: [log in to unmask]
> Subject: [SPM] SPM8b segmentation and structural volume size
>
>
> I am a newbie in fMRI. We have just activated the fMRI functionality on our
> Siemens Avanto 1.5T machine and have carried out our very first finger
> tapping experiment! The structural image data size is 256x256x176 with
> pixel dimension of [0.9766 0.9766 1] and the functional 64x64x34 with
> pixel dimension of [3 3 3.75]. The segmentation process on SPM8b takes
> longer than I can bear waiting for it to complete! I have waited for an
> hour of going over 1500 iterations with no convergence in sight! Am I
> doing something silly? Any help on this would be really appreciated.
>
> Bahman
>
>
>
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