Hi Laura,
it depends on how the data was acquired. These days we find that 3T multi-channel data you are probably better off avoiding the blurring associated with motion correction and averaging, and thta 1 volume is better. On the other hand if it's 1.5T single channel data at 1mm it may be too noisy with just a single acquisition. cheers Bruce On Fri, 28 May 2010, pikase@tin.it wrote:
Hi everyone,
maybe this is a trivial question but I didn't find an answer in the archives, so I'll post it anyway. I've noticed in articles on cortical thickness using freesurfer that the number of initial T1 volumes (orig) is quite variable, ranging from 1 to 3 or 4. We are planning to evaluate the cortical thickness for a large sample (30/40 subjects), and we have 1 volume for each subject (3T, 200 slices. 1mm). I was wondering whether using a single volume could affect the results. However, I've already processed 15 subjects and the results look nearly perfect to me.
Best regards
Laura