Agreed, especially so with MD. Keep in mind that you¹re upsampling MD from a lower-res (diffusion) space to a higher-res (T1) space, so it should be smooth already, relatively to measure derived from the T1. And MD varies pretty smoothly (it¹s a mean of 3 things, after all).
On 8/11/17, 1:11 PM, "Bruce Fischl" <fis...@nmr.mgh.harvard.edu> wrote: >Hi Shane > >not really - it totally depends on the size of the effect you are looking >for. I would be *very* careful about partial volume effects though > >cheers >Bruce >On Fri, >11 Aug 2017, Shane Schofield wrote: > >> Appreciate it Dr Bruce. Do you have guidelines for smoothing MD? >> >> Dr Yendiki, I am trying to investigate whether cortical MD can be a >>marker >> of neurodegeneration. The idea is that during the early stages of a >>disease, >> cellular microstructure may breakdown before cortical thinning occurs. >>This >> results in "less" barriers against diffusion resulting in an increase of >> MD. >> >> >> On Friday, August 11, 2017, 5:49:40 PM GMT+1, Bruce Fischl >> <fis...@nmr.mgh.harvard.edu> wrote: >> >> >> Hi Shane >> >> you probably don't need cvs as it is more to extend the surface-based >> registration to the entire volume. Here you just need the surface-based >> registration I believe. Use mri_vol2surf to sample the FA onto the >>surface. >> After that it is identical to a thickness study >> >> cheers >> Bruce >> >> >> >> On Fri, 11 Aug 2017, Shane Schofield >> wrote: >> >> > Thanks Dr Yendiki. >> > >> > I am more interested to compare MD in grey matter regions by putting >>the >> MD on the surface, and then do a glmfit type of comparisons. Is that OK? >> Would you recommend me >> > to smooth the data after spatial normalisation? I have also used the >> mri_cvs_register as described on the tutorial. >> > >> > >> > On Friday, August 11, 2017, 7:03:49 AM GMT+1, Shane Schofield >> <shane.schofi...@yahoo.com> wrote: >> > >> > >> > Hi DTI Experts, >> > >> > Is it sensible to do comparisons of MD on the cortex surface like a >>normal >> cortical thickness comparisons between group? If the answer is yes, are >> there recommended on >> > smoothing ? >> > >> > DT_RECON has been completed in Freesurfer. >> > >> > Thank you. >> > >> > >> > >> _______________________________________________ >> 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. >> _______________________________________________ Freesurfer mailing list Freesurfer@nmr.mgh.harvard.edu https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer
