help > .img / .nii differences in outlier detection
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Jun 8, 2017 11:06 AM | Patrick McConnell - MUSC
.img / .nii differences in outlier detection
Hello,
We recently noticed that differences in outlier detection are observed when using analyze format (.img/.hdr) vs 4D nifti (.nii) format images. While the motion parameters appear identical for a single subject, upon closer inspection the scale (in mm) is slightly different between the two processing pipelines. Screenshots of the two art outputs are attached (analyze on top, nii on bottom). Both images were converted from dicom to img or nii using dcm2nii, and converted from 4D to 3D in SPM prior to any preprocessing steps. After unpacking, images were then slice time corrected, realigned and unwarped (all in SPM12).
I realize that this may not be an Art toolbox specific issue, but any help in understanding what might cause this is greatly appreciated!
Thank you,
Patrick
We recently noticed that differences in outlier detection are observed when using analyze format (.img/.hdr) vs 4D nifti (.nii) format images. While the motion parameters appear identical for a single subject, upon closer inspection the scale (in mm) is slightly different between the two processing pipelines. Screenshots of the two art outputs are attached (analyze on top, nii on bottom). Both images were converted from dicom to img or nii using dcm2nii, and converted from 4D to 3D in SPM prior to any preprocessing steps. After unpacking, images were then slice time corrected, realigned and unwarped (all in SPM12).
I realize that this may not be an Art toolbox specific issue, but any help in understanding what might cause this is greatly appreciated!
Thank you,
Patrick