Hi Martin,

thanks for your quick reply. I was indeed referring to the quality check. I 
guess I interpreted that incorrectly. With the children data "inspecting" 
almost always means "editing".

I also took a look at the cheat sheet again. I've been mulling it over and my 
best idea so far is to 

1. check/ edit the crosses for control points and rerun autorecon2-cp 
-autorecon3 since those get transferred to the long directly 
2. check the base and edit the brainmask (eg taking out blood vessels and 
tentoral membrane or cloning voxels if necessary) since it gets transferred to 
the long directly
3. check the base and edit the wm mask and rerun -autorecon2-wm -autorecon3 in 
the base command
4. check the longs and hope everything is fine :)

We measured the 4 year olds with a gap of 3 weeks between scans with the 
assumption that their heads won't grow considerably within 2 months time. What 
do you think?
Cheers, Clara

----- Ursprüngliche Mail -----
Von: "mreuter" <mreu...@nmr.mgh.harvard.edu>
An: "Freesurfer support list" <freesurfer@nmr.mgh.harvard.edu>
Gesendet: Donnerstag, 28. Mai 2015 16:45:57
Betreff: Re: [Freesurfer] what order for longitudinal edits

Hi Clara,

how to edit depends a lot on the type of edit. The general rule is to 
edit as early as possible. In some edits, there is shortcuts (e.g. start 
with base, then check long and skip the cross). Take a look at the Cheat 
Sheet on the first link. Also usually there is no need at all to edit 
the longs, as the edits in cross and base should fix everything 
sufficiently. So in the case of a shortcut (editing base, skipping 
cross) you only need to edit 1 run (the base) per subject, not all 3 
time points.

I also cannot find the contradiction in the first page. Where does it 
say to start editing with the longs, then go backwards? That would 
certainly be wrong for editing. Can you please point me to that, so I 
can fix it (if it is there). Maybe you confused this with QC (quality 
check) which you could do backwards to save time. E.g. if the longs are 
look great, no need to check base and cross.

"QC from back to front (long -> base -> cross), once you find where 
problems occur, edit from front to back (cross -> base -> long)."

Cheers, Martin

P.S. probably more important, I doubt that the longitudinal stream will 
work well on 4-year olds. The basic assumption is that head size does 
not change, so if that is approximately true, it could work (e.g. short 
time intervals). Otherwise you may run into lot's of editing problems 
and it may be easier to just use the cross sectionals in your analysis 
(at the cost of increased measurement variability).


On 05/28/2015 10:19 AM, Clara Kühn wrote:
> Dear Freesurfer Experts,
>
> I'm working with the structural data of 4-year olds which we measured 3 times 
> to asses changes in cortical thickness.
> During the preprocessing I've found some contradicting information on how to 
> best edit the longitudinal data. On this site 
> https://surfer.nmr.mgh.harvard.edu/fswiki/LongitudinalEdits it says to edit 
> stuff as early as possible. However, on the same site it says to start with 
> the longs, then the base and then the cross. And on this site 
> https://surfer.nmr.mgh.harvard.edu/fswiki/FsTutorial/LongitudinalTutorial#FsTutorial.2BAC8-LongitudinalTutorialfreeview.EditingLongitudinalData
>  it says to check the base first and then the longs.
> I am utterly confused as to how I can edit my data most efficiently because I 
> have a lot of it (100 children, 3 scans each).
>
> To me, it is also unclear at which point I can edit the long and rerun the 
> recon process partially (eg. with the -wm flag) and when it is necessary to 
> go back to the base...
>
> I am very thankful for any kind of revelation on these matters :)
> Cheers,
> Clara Kühn
>
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> Freesurfer@nmr.mgh.harvard.edu
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>

-- 
Dr. Martin Reuter

Instructor in Neurology
   Harvard Medical School
Assistant in Neuroscience
   Dept. of Radiology, Massachusetts General Hospital
   Dept. of Neurology, Massachusetts General Hospital
Research Affiliate
   Computer Science and Artificial Intelligence Lab,
   Dept. of Electrical Engineering and Computer Science,
   Massachusetts Institute of Technology

A.A.Martinos Center for Biomedical Imaging
149 Thirteenth Street, Suite 2301
Charlestown, MA 02129

Phone: +1-617-724-5652
Email:
    mreu...@nmr.mgh.harvard.edu
    reu...@mit.edu
Web  : http://reuter.mit.edu

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