Dear Martin, thank you for the feedback. I read the wiki but the instructions concerning aseg edits were not much clear for me. And, I was misinformed by -noasegfusion option.
The pity with aseg errors is that with the current design and when the error is large to affect surfaces in base, it is necessary to edit the same error twice. Since the aseg of base is not initialized from cross, and long is not initialized from base, then one has to edit the same error both in base and in long (or cross). If there is a systematic error which affects all timepoints (as it is in my case - I have 2 points), I effectively have to edit the same error 3 times. It is quite large error affecting whole posterior part of lateral ventricle (see screenshot). Therefore, I thought that best option would be to edit the base and initialize long from base using -noasegfusion. I tried to do that by manually copying aseg from base and manually running mri_ca_label with -r and -ri option (and and the error is (almost) cleaned in long. Why do you think that the initialization from base is worse/undesirable than initialization from fused aseg from cross? It seems to me that to initialize from fused (averaged) asegs of cross or initialize from aseg of base (which is averaged template of cross) is methodologically quite similar, should produce similar results and in terms of edits it is much more convenient way. Regards, Antonin Hi Antonin, the -noasegfusion is not really supported and a left over from initial testing when we first developed the stream. I will take a look at it and probably remove the flag (or implement it in a way that it really initializes with the aseg from the base, although I think this is not desirable, unless one really assumes there is no/ or very little change between time points. About aseg edits in longitudinal processing, please look at our edit wiki page: https://surfer.nmr.mgh.harvard.edu/fswiki/LongitudinalEdits#aseg.mgz <https://surfer.nmr.mgh.harvard.edu/fswiki/LongitudinalEdits#aseg.mgz> “ ASEG edits can be done in cross, base and long. Recommendation: Edit in long only if you want to correct the volume of important structures. Edit in base if surfaces need to be changed due to incorrect labeling of aseg. Not necessary to edit in cross. The segmentation in the long runs is initialized with a fused aseg (a weighted average of the cross sectional asegs). Thus any edits done to the cross sectionals are incorporated indirectly into the long stream. But since the fused aseg is used only for the initialization, it can happen that manual edits from the cross get removed again. Therefore, to correct the volume, just edit the long." So for your ventricle correction, you could either clean up the cross data and hope it caries over to the long (it should), or directly edit the long aseg. Best, Martin > On 16 Jan 2017, at 23:23, Antonin Skoch <[email protected]> wrote: > > Dear experts, > > I am testing the longitudinal stream with V6beta version. > > The recon-all -help says for -noasegfusion: > > Do not create 'fused' aseg from the longbase timepoints, which would normally > be used to initialize the ca_labeling. Instead, initialize using the longbase > aseg.mgz. > > As I looked to recon-all code it seems that in case of -noasegfusion there is > no use of -r and -ri parameters and therefore no "initialization". Could you > please comment on? > > My second query is regarding manual edits: > > In one subject the manual editing of aseg was necessary due to ventricle > mislabeling. I edited the aseg.presurf in base template and subsequently run > longitudinal stream via > > recon-all -long tpID templateID -noasegfusion -all > > From the last sentence of -noasegfusion help I (wrongly) expected that my > aseg.presurf edits in base template would be incorporated for -long recon. > However, this was not the case, the edits have not been incorporated at all. > Looking at the recon-all code the aseg.presurf from base is never used for > -long. > > I thought that I could incorporate manual edits from base by manual copying > of aseg.presurf from base to long directory. As I looked for the way how the > manual aseg edits are handled in recon-all, they are identified by using the > difference between the files aseg.auto and aseg.manedit which contains manual > edits. Therefore I think that the copying from base is not an option, I > expect that this would replace segmentations not only in manual edit regions, > but in all regions where the aseg.auto of base and aseg.auto of -long differs > (they do not have the same input) which is undesirable. So I think I do not > have any other option than to edit aseg.presurf in -long again. > > Could you please comment on how to optimally handle such situations? > > Regards, > > Antonin Skoch > _______________________________________________ > Freesurfer mailing list > [email protected] > https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer
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