Dear Petr, the volumes from the subfields are in voxels. Since the voxels are 0.5mm isotropic, their volumes is (1/8) cubic millimeters. Therefore, you need to divide the volumes by 8 to convert to mm3. Kind regards, /Eugenio
Juan Eugenio Iglesias Postdoctoral researcher BCBL www.jeiglesias.com www.bcbl.eu Legal disclaimer/Aviso legal/Lege-oharra: www.bcbl.eu/legal-disclaimer ----- Original Message ----- From: "zach petr" <zach.p...@post.cz> To: "Freesurfer support list" <freesurfer@nmr.mgh.harvard.edu> Sent: Tuesday, April 15, 2014 4:05:43 PM Subject: Re: [Freesurfer] FS volume discrepancies Thanks for reply. But adding subfield volumes together leads to too high number compared to overall hippocampus volume. Like 9500 mm3 compared to 2.1 mm3. Petr ---------- Původní zpráva ---------- Od: Bruce Fischl <fis...@nmr.mgh.harvard.edu> Komu: Freesurfer support list <freesurfer@nmr.mgh.harvard.edu> Datum: 15. 4. 2014 14:35:13 Předmět: Re: [Freesurfer] FS volume discrepancies >From Eugenio: ------------------------ Dear Petr, at this point, the hippocampal subfield module is - to some extent - independent from the whole hippocampal segmentation. The values you will obtain from adding the subfield volumes together will be around 15% lower than the volumes from aseg.stat, but they will still be very highly correlated. Kind regards, ------------------------ On Tue, 15 Apr 2014, zach.p...@post.cz wrote: > > I have several issues concerning automated volumes calculation. When you > look at the aseg.stat for hippocampal volume (in mm3) it gives different > value compared to hippocampal subfields volume calculation (which comes in > voxels but there is stated that 1 voxel is 0.5mm3). How is it possible? I > presume that anatomical definition and subfield incorporation is the same. > > Next - if you look at the whole hippocampal formation volume in hippocampal > subfield calculations it is way lower compared to the summation of the > CA1-CA4 + dentate gyrus = hippocampal formation. What could be explanation > of this? > > Petr > > > _______________________________________________ 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. _______________________________________________ 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. _______________________________________________ Freesurfer mailing list Freesurfer@nmr.mgh.harvard.edu https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer
