Hi Martin:
But, between version 5.3 and 6.0 there are any differences in the algorithms for subcortical volume, cortical thickness, etc., or only additions to that, such as the hippocampus or brainstem subfields ?... and in general, if I segment for example the same healthy control in freesurfer 5.3 and 6.0 in the same operating system, there will be any difference in subcortical volumes and/or cortical thickness ?...
Sincerely,
Gonzalo Rojas Costa Laboratory for Advanced Medical Image Processing Department of Radiology Clínica las Condes Lo Fontecilla 441, Las Condes, Santiago, Chile. Tel: 56-2-2105170 Cel: 56-9-97771785 www.clc.cl
On Wed, Nov 11, 2015 at 7:57 AM, freesurfer-request@nmr.mgh.harvard.edu wrote:
Message: 24 Date: Tue, 10 Nov 2015 16:57:43 -0500 From: Martin Reuter mreuter@nmr.mgh.harvard.edu Subject: Re: [Freesurfer] 5.3 vs 6.0 volumetric differences... To: Freesurfer support list freesurfer@nmr.mgh.harvard.edu Message-ID: 56426857.3030804@nmr.mgh.harvard.edu Content-Type: text/plain; charset=utf-8; format=flowed
Hi Gonzalo,
of course.
There is even a difference when running the same FS version with a different operating system (due to differences in the numerical libraries, optimizations etc).
Are changes big or small? In a single case they can be very big (it could be a case that failed in 5.3 and works with 6.0 - or the other way)
Are changes directional (significantly larger or smaller volumes/thickness)? Hard to say and hard to detect if small, but it can happen due to a new algorithm that measurements are consistently larger (/smaller) than in another version. We try to avoid this, but it can theoretically happen.
That is why it is so important to stick with the same version and operating system when processing data.
Best, Martin
On 11/10/2015 04:48 PM, Gonzalo Rojas Costa wrote:
Hi:
There are any difference between subcortical structures volume, cortical thickness, supratentorial volume, gray matter volume, etc. computed with freesurfer 5.3 and 6.0 ?...
Sincerely,
Gonzalo Rojas Costa
-- Martin Reuter, PhD Assistant Professor of Radiology, Harvard Medical School Assistant Professor of Neurology, Harvard Medical School A.A.Martinos Center for Biomedical Imaging Massachusetts General Hospital Research Affiliate, CSAIL, MIT Phone: +1-617-724-5652 Web : http://reuter.mit.edu
Hi Gonzalo,
yes there are changes to many of the algorithms (sometimes bug fixes or improvements, sometimes parameter changes etc) which will generate different results. It can happen in individual cases that subcortical volume or cortical thickness differs a lot between 5.3 and 6.0, even when running on the same operating system. It is unlikely that this will change results of a study with sufficient power (group comparison).
Best, Martin
On Nov 11, 2015, at 10:08 PM, Gonzalo Rojas Costa gonzalo.rojas.costa@gmail.com wrote:
Hi Martin:
But, between version 5.3 and 6.0 there are any differences in the algorithms for subcortical volume, cortical thickness, etc., or only additions to that, such as the hippocampus or brainstem subfields ?... and in general, if I segment for example the same healthy control in freesurfer 5.3 and 6.0 in the same operating system, there will be any difference in subcortical volumes and/or cortical thickness ?...
Sincerely,
Gonzalo Rojas Costa Laboratory for Advanced Medical Image Processing Department of Radiology Clínica las Condes Lo Fontecilla 441, Las Condes, Santiago, Chile. Tel: 56-2-2105170 Cel: 56-9-97771785 www.clc.cl
On Wed, Nov 11, 2015 at 7:57 AM, freesurfer-request@nmr.mgh.harvard.edu wrote:
Message: 24 Date: Tue, 10 Nov 2015 16:57:43 -0500 From: Martin Reuter mreuter@nmr.mgh.harvard.edu Subject: Re: [Freesurfer] 5.3 vs 6.0 volumetric differences... To: Freesurfer support list freesurfer@nmr.mgh.harvard.edu Message-ID: 56426857.3030804@nmr.mgh.harvard.edu Content-Type: text/plain; charset=utf-8; format=flowed
Hi Gonzalo,
of course.
There is even a difference when running the same FS version with a different operating system (due to differences in the numerical libraries, optimizations etc).
Are changes big or small? In a single case they can be very big (it could be a case that failed in 5.3 and works with 6.0 - or the other way)
Are changes directional (significantly larger or smaller volumes/thickness)? Hard to say and hard to detect if small, but it can happen due to a new algorithm that measurements are consistently larger (/smaller) than in another version. We try to avoid this, but it can theoretically happen.
That is why it is so important to stick with the same version and operating system when processing data.
Best, Martin
On 11/10/2015 04:48 PM, Gonzalo Rojas Costa wrote:
Hi:
There are any difference between subcortical structures volume, cortical thickness, supratentorial volume, gray matter volume, etc. computed with freesurfer 5.3 and 6.0 ?...
Sincerely,
Gonzalo Rojas Costa
-- Martin Reuter, PhD Assistant Professor of Radiology, Harvard Medical School Assistant Professor of Neurology, Harvard Medical School A.A.Martinos Center for Biomedical Imaging Massachusetts General Hospital Research Affiliate, CSAIL, MIT Phone: +1-617-724-5652 Web : http://reuter.mit.edu
freesurfer@nmr.mgh.harvard.edu
-
Gonzalo Rojas Costa -
Martin Reuter