Hi Torsten,



The next question is then about the MRI acquisition. I was advised from one
side that aqcuisiton parameters between disease and normal should be
identical, including receiver gain. From another source I've been advised to
let the machine sort out the right settings so that, ie a 180 degree pulse
is achieved, which may not be the case with identical gain settings. However
one may argue that the difference in gain settings is due to the disease
when all other parameters are constant and therefore should not be changed
either (ie. should be identical throughout the study). On the other hand
letting the machine adapt the pulse may actually mask a real difference.
This is probably not the right forum to post this question to, but maybe
someone can give advise anyway.

My advice would be to stick to quantitative measurements such as ADC and diffusion tensor etc. if you want to compare your populations.
If you observe differences in S0, you would struggle to interpret them.



Thanks in advance,

Torsten


Saad Jbabdi
Oxford University FMRIB Centre

JR Hospital, Headington, OX3 9DU, UK
+44 (0) 1865 222545  (fax 717)