Hi Daniel,
in the segmentation function you can specify to write out the bias
corrected image (default). The filename starts with prefix m. You can
calculate the bias field by dividing the corrected image (ms*.nii for
MPRAGE and mf*.nii for EPI) voxelwise by the uncorrected image. You can
apply this bias field just by voxelwise multiplikation with the other EPIs.
Hope that helps
Michael.
Am 14.11.2012 21:15, schrieb Daniel Sheltraw:
> Hi
>
> A 2012 NeuroImage paper by Bandettini et al titled "Effects of image
> contrast on functional MRI image registration" states the following:
>
>
> "Intensity inhomogeneity corrected datasets (both EPI and MPRAGE) were
> computed using the segmentation function available in SPM8
> (www.fil.ion.ucl.ac.uk/spm/software). For steady-state EPI data, intensity
> correction was computed based on the bias maps computed for the sixth volume
> of each angle and each subject separately."
>
> The authors are trying to correct for image inhomogeneity due primarily to
> receive field and transmit field inhomogeneity.
>
> Does anybody know which SPM function in particular the authors used and what
> the algorithm is for it?
>
> Thank you,
> Daniel
>
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Dr. Michael Erb
Dept. Biomedical Magnetic Resonance
University Hospital Tübingen
Hoppe-Seyler-Str. 3
72076 Tübingen, Germany
Tel.: +49(0)7071/2987753 priv. +49(0)7071/61559
Fax.: +49(0)7071/294371
e-mail: <[log in to unmask]>
www:
http://www.medizin.uni-tuebingen.de/Forschung/Kliniken/Radiologie/Biomedizinische+Magnetresonanz.html
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