External Email - Use Caution Site effects, even from different scanners with comparable sequences, are a big issue is neuroimaging and discussed in many papers. I think you should be very careful with interpretation of results, especially since in your case, the scanners were different between the groups (!) and additionally operating at different T settings.
Tim > On August 6, 2020 at 6:16 AM Haewon Roh <[email protected]> wrote: > > > External Email - Use Caution > > Hi. > > Recently, I analyzed patients who have taken 1.5T MRI ; (Because they had > to go in MRI room with some metal materials) and normal controls who took > 3.0T MRI. And, after recon and preprocessing of each group of patients and > controls in freesurfer v6, I've found that many cortices of patients (1.5T > MRI) were significantly reduced, compared with normal age-sex matched > controls (3.0T MRI). When I searched in order to know if there is > difference between 1.5T vs 3.0T MRI and magnetic field can make a huge > difference in calculating volumes or thickness of cortices in Freesurfer, I > can find only one article by Heinen and his colleague, reporting there is > no big difference and different(1.5 vs 3.0T) magnetic field strength cannot > make a significant difference. (Plos ONE, 2016) > > Furthermore, given that data which is taken in 1.5T MRI is more likely to > have more increased volumes or thickness of cerebral cortices than those of > 3.0T MRI, I think that reduced cortical volumes which are calculated using > 1.5T MRI have more significance than controls of 3.0T MRI... > > Is it true that different magnetic strengths of MRI cannot change the > result significantly in Freesurfer? > > Thank you always! > > > -- > Hae Won ROH, M.D. > > H.P: +82-10-4341-8142 > E-mail: [email protected] > _______________________________________________ > Freesurfer mailing list > [email protected] > https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer -- Dr. Tim Schäfer Postdoc Computational Neuroimaging Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy University Hospital Frankfurt, Goethe University Frankfurt am Main, Germany _______________________________________________ Freesurfer mailing list [email protected] https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer
