Hi Anastasia, An independent T-test on the aseg.stats "WM-Hypointensties" (SegId 77) showed that the mean WM hypointensities volume of the patient group (1378.8mm3, SD 650mm3) did not significantly differ from the controls (1120.8mm3, SD 372mm3; p=.111). A Pearson and Spearman correlation analysis found no correlation of WMH volume with tract volumes but did find a correlation with FA in three of the nine tracts of interest (Forceps minor, left ATR, left ILF). I reviewed the T2-FLAIRs for the subjects with the highest volumes of WM lesions and they were all dirty-appearing white matter around the ventricles rather than punctate WMH within the regions of these tracts.
The tracts look reasonable in Freeview… <scratching head> Sean On 4/04/13 7:17 AM, "Anastasia Yendiki" <ayend...@nmr.mgh.harvard.edu<mailto:ayend...@nmr.mgh.harvard.edu>> wrote: Hi Sean - Can you check their freesurfer aseg's and see if any of the white matter was classified as a hypointensity there? a.y On Wed, 3 Apr 2013, Sean Hatton wrote: This is Tracula 5.2 with FLIRT and the vectors are correctly aligned (V1 over FA). >From the literature and what is seen in my TBSS is reduced FA in the minor >forceps and ATR. These are young (23yo) psychiatric so age related atrophy is not expected. However, they are known to have WM hypointensities even at a young age, I can review their T2s. A few are on mood stabilizers, but if this affected FA I would also see it in TBSS. Thoughts? Anastasia Yendiki <ayend...@nmr.mgh.harvard.edu<mailto:ayend...@nmr.mgh.harvard.edu>> wrote: Oh, another question: do your patients have white-mater hypo/hyper-intensities, in other words any voxels in the white matter that are classified as something other than white matter in the freesurfer aseg? On Wed, 3 Apr 2013, Sean Hatton wrote: > Hi Freesurfer gurus, > > I have been using Tracula to investigate white matter abnormalities in a > patient > cohort (n=20) compared to matched controls (n=40). In line with the > literature, we > expected to see reductions in FA in the patients' tracts but instead they have > significantly higher FA means. To double-check, we ran TBSS over the same > cohorts and > got the results as per the literature (I.e. reduced FA in the patient group). > The FA, > RD, AD, MD and volume outputs are normally distributed and there are no > extreme > outliners. So wondering: > 1. The patient group had significantly reduced tract volumes. If this volume > calculation is incorrect I expect it could influence the calculation of > the mean > FA, RD, AD etc. Is there a way of checking the volume and subsequent > calculations? > 2. Yendiki et al 2011 had no corrections – do I need corrections? > 3. Should I be thresholding tract stats? > Thank you in advance, > > Sean Hatton > Brain and Mind Research Institute > University of Sydney > > > > > > > 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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