Dear FS experts In one of our paper, I tried to explain how FS is able to produce cortical thickness maps in a spatial resolution that go beyond the resolution of the original MRI acquisition.
We wrote the following: The thickness maps produced are not limited to the voxel resolution of the image and thus sensitive for sub-millimeter differences between groups (Fischl, Dale 2000). The way in which the resolution of the cortical thickness maps goes beyond the resolution of the original acquisition can be imagined as a (conventional) partial volume correction procedure. The cortex is smooth at the spatial scale of a couple of millimeters, which is imposed as constraint by FreeSurfer to estimate the location of the surface with subvoxel accuracy. For instance, if a given voxel is darker than its neighbouring grey matter it probably contains more CSF and so the surface model is at a slightly different position than if the neighbouring voxels were brighter and therefore contain probably more white matter. Now, the reviewer says that we are to vague in our description. He would like to know what is exactly meant by a "couple of millimeters". Is this 1-3 mm or rather 3-5 mm or any other value? Thanks in advance for any suggestion Regards Jürgen Hänggi ---------------------------------------------------------------------------- Jürgen Hänggi, Ph.D. Division Neuropsychology Institute of Psychology University of Zurich Binzmuehlestrasse 14, PO Box 25 8050 Zurich, Switzerland 0041 44 635 73 97 (phone office) 0041 76 445 86 84 (phone mobile) 0041 44 635 74 09 (fax office) BIN 4.D.04 (office room number) j.haenggi[at]psychologie.uzh.ch (email) http://www.psychologie.uzh.ch/neuropsy/ (website) http://www.juergenhaenggi.ch (private website) This e-mail (and any attachment/s) contains confidential and/or privileged information. If you are not the intended recipient (or have received this e-mail in error) please notify the sender immediately and destroy this e-mail. Any unauthorised copying, disclosure or distribution of the material in this e-mail is strictly forbidden. ---------------------------------------------------------------------------- _______________________________________________ Freesurfer mailing list Freesurfer@nmr.mgh.harvard.edu https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer The information in this e-mail is intended only for the person to whom it is addressed. If you believe this e-mail was sent to you in error and the e-mail contains patient information, please contact the Partners Compliance HelpLine at http://www.partners.org/complianceline . If the e-mail was sent to you in error but does not contain patient information, please contact the sender and properly dispose of the e-mail.
