Dear Bruce Fischl ?h.white.H, ?h.curv, and H Mean reflected the vector fields with 'sign(+ or -)', and MeanCurv reflected the integral of the 'absolute' value of mean curvature. Am I understanding this correctly?
Best Wishes, Han On Mon, Oct 3, 2016 at 7:49 AM, Bruce Fischl <fis...@nmr.mgh.harvard.edu> wrote: > Hi Han > > I'm not sure I understand you question. The sign of the curvature depends > on the arbirary convention you choose for the normal vector field over the > surface. We pick and outwards pointing normal, which means that gyral > regions in general have negative curvature (since they lie 'below' the > tangent plane in terms of their dot product with the normal) and sulcal > ones are positive. AFAIK both the ?h.white.H and ?h.curv curvatures obey > this convention, although the smoothing applied to the ?h.curv will mean > that some places they will have different sign. If you plot them both you > will see that they are pretty highly correlated though. > > Does that answer your question? If not, can you clarify? > > cheers > Bruce > > > > > On Sun, 2 Oct 2016, Hanbyul Cho wrote: > > Dear FreeSurfer Team, >> >> I apologize for the repetitive questions. >> >> I made 2 labels which included bilateral paracentral lobule and sulcus >> regions. >> Then I extract the values: >> - MeanCurv >> After mris_anatomical_stats processing, I extracted the MeanCurv by >> the >> command, >> 'aparcstats2table --hemi ?h --parc <label> --meas meancurv --subjects >> <subjects list> --tablefile <output.txt>' >> >> - ?h.Curv >> After mris_anatomical_stats processing with the option '-t >> lh.curv', I >> extracted the curvature value by the command, >> 'aparcstats2table --hemi ?h --parc <label> --meas thickness--subjects >> <subjects list> --tablefile <output.txt>' >> >> - H <mean> +- <std>, H Mean Rectified Surface Integral >> The Mean curvature values were compute by the command, >> 'mris_curvature_Stats -l <label> -g -n -m -f white -o <output.txt> >> <subject> ?h' >> >> I analyzed the each value. The ?h.Curv mean (within the label) has >> opposite >> relationship with Z value compared to MeanCurv, while similar relationship >> with Z value compared to H <mean>. >> >> I heard that the MeanCurv is the integral of the rectified mean curvature >> of >> white matter surface (1/r mm), and ?h.curv is the mean curvature of the >> white matter surface with a Gaussian smoothing kernel applied. >> It looks that the MeanCurv and H Mean Rectified Surface Integral has only >> positive values, while the H <mean> and ?h.curv has positive or negative >> value. >> >> I wonder whether MeanCurv and ?h.curv has the difference meaning or >> difference formula. >> And I would like to know the meaning of the ?h.curv negative value. >> Is H <mean> ( by mris_curvature_Stats ) compute from ?h.curv ? >> >> >> Thank you. >> >> Han. >> >> >> > _______________________________________________ > 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. > >
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