On Apr 14, 2020, at 1:14 PM, Renner, Brian <Brian.Renner@cshs.org> wrote:

        External Email - Use Caution        

Hey Andrew;

Thanks for the response! To answer your questions, yes, We’re all respectively on Macbook Pro retina displays. I hadn't compared the visualization on a Windows machine, though I ostensibly could in the near future. I have loaded up single vs. multiple volumes and noticed what you say; would it be best to load the hypothetical highest resolution scan first? ie. freeview -v highest.nii lower.nii. lowest.nii. --trilinear?

An example picture of this is shown below, with a standard 1mm^3 t2 flair loaded in freeview with a higher resolution t2* as the first loaded scan, ie. on the left freeview -v t2*file flair --trilinear vs. fsleyes t2*file flair on the right:

<Screen Shot 2020-04-14 at 9.40.57 AM.png>

Fig 1. This is the flair file compared side by side (fv --trilinear vs. fsleyes, respectively).

<Screen Shot 2020-04-14 at 9.43.58 AM.png>

Fig 2. This is the t2*file (0.65mm voxel width), which has both noticeable quality drop and a different baseline intensity threshold at baseline between freeview and fsleyes. 

<Screen Shot 2020-04-14 at 10.00.10 AM.png>

Fig 3. This is the flair --trilinear vs. flair (noflags) vs. fsleyes flair, respectively.

 Let me know what you think, and again thank you for the response!

BR

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From: freesurfer-bounces@nmr.mgh.harvard.edu <freesurfer-bounces@nmr.mgh.harvard.edu> on behalf of Hoopes, Andrew <AHOOPES@mgh.harvard.edu>
Sent: Tuesday, April 14, 2020 9:25:08 AM
To: Freesurfer support list <freesurfer@nmr.mgh.harvard.edu>
Subject: [External] Re: [Freesurfer] Freesurfer display resolution very low compared to other viewers

 

Hi Brian,

 

A couple questions - are you visualizing on a mac retina screen? If so, there will be a slight decrease from the standard resolution because the underlying rendering library that we use unfortunately does not support retina capabilities at this time. Also, are you loading single or multiple volumes? Freeview uses the first volume loaded as the base image geometry, and all the following volumes are resampled (if necessary) into this base geometry using nearest neighbor interpolation. So if you’re working with different-resolution images, it might help to enable linear interpolation as the default resampling method by using the `--trilinear` freeview flag. If that’s not the case, it’d be helpful to see a couple screenshots of the issue.

 

Hope that helps,

Andrew

 

From: <freesurfer-bounces@nmr.mgh.harvard.edu> on behalf of "Renner, Brian" <Brian.Renner@cshs.org>
Reply-To: FS Help <freesurfer@nmr.mgh.harvard.edu>
Date: Monday, April 13, 2020 at 8:54 PM
To: FS Help <freesurfer@nmr.mgh.harvard.edu>
Subject: [Freesurfer] Freesurfer display resolution very low compared to other viewers

 

        External Email - Use Caution        

Hello all! 

 

Inaugural message to the list; I will attempt to be brief with the project description.

 

The setup is consistent between both versions 6.0.0 and 7.0.0-beta, run on a high performance cluster, accessed through macOS terminal + Xquartz, most recent versions all.

 

As it stands, our group is attempting to do subfield analysis of hippocampal analysis and lesion measurement in MS subjects. We have noticed that there is a major discrepancy of resolutions between files, which has irked some of our physicians undertaking the lesion measurement. We need to resolve the lesions down to 3mm and have noticed the quality between freeview and fsleyes of the same nifti files will yield much lower display resolution. This is true for most scans, though it has been compared using 1mm T2 FLAIR sequences as well as T2* sequences with 0.65mm voxel space. I have been attempting to find a workaround as the current solution for the physicians is to look at the files in fsleyes and then measure them with the ruler tool in freeview. I can send supporting pictures as necessary. 

 

Thank you in advance for any thoughts you may have!

 

BR

 

--

Brian Renner, MD
Research Associate, Neurology 
brian.renner@cshs.org

Cedars-Sinai
127 S. San Vicente Blvd, Suite A6600  :  Los Angeles CA 90048
office 310-423-1589  :  mobile 310-658-3492  :  cedars-sinai.org 

 

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