The diffusion coefficient of free water at body temperature is 0.003
mm^2/s to 1 significant figure.
The Apparent diffusion coefficient in brain parenchyma depends a bit
on a few things including your diffusion time and where exactly you
are, but at standard b-values in white matter, it might be around
0.0012 mm^2/s along the orientation of the axons, and around 0.0004
mm^2/s perpendicular to this axis. The mean diffusivity should
therefore be around (0.0012+0.0004+0.0004)/3 =0.0007mm^2/s to 1
I suspect you can make the image appear less bright by simply
changing the brightness/contrast scales in fslview.
On 31 Mar 2008, at 23:24, Elisa Canu wrote:
> I've just ran FDT on my images, but I'm no happy with the MD outputs.
> These images look brighter than your examples and the intensity of
> is around 0.00317345 inside the ventriculs and about 0.000751132
> Is that a problem with the procedure (I've done something wrong!)
> or it's
> just a problem of scaling and I need to multiply my indices 10000 or
> Thanks a lot,