I think it should work for b0 images, but I would avoid using any frames that have a gradient. Note that you will need about 10 images to compute the fwhm using mri_fwhm (also make sure you use a mask)

On 8/30/2022 1:33 PM, Igor Nestrašil wrote:

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Dear FreeSurfer developers,

Can "mri_fwhm" be used to estimate FWHM of b0 images (obtained from diffusion-weighted echo-planar sequences) and is it possible to employ for FWHM estimation from aligned diffusion-weighted images of the same b-value but varying gradient wave vectors?

Thank you!

Igor Nestrasil U of Minnesota

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