Hi Markus,
> Thanks for your diverse input ;-)
That's science :)
> @Marko: Yes, I plan to compare each patient to the healthy data base of
> 70 patients (detection of local pathology).
[...]
> So is the difference of 1 additional patient in the 70 other subjects
> really critical, given the smoothing, the SNR etc.?? Has this been
> evaluated?
Not sure this has been evaluated rigorously, but my usual point is: what
do you reply to a reviewer who asks you to demonstrate why the
difference between subjects that you see in the end is not due to a
difference in data processing? And your answer is going to be "I hope it
is not" because you cannot prove it. If you have processed your controls
in a systematically different way than your patient, this is simply an
irreconcilable difference that you cannot make up. It is like scanning
children on one scanner and adults on another scanner and then finding
the effects of age. You cannot, as age is confounded by scanner
difference. In how far this effect is huge, I cannot tell you, but then
again, you do not usually look for huge effects in a patient anyway.
Cheers,
Marko
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PD Dr. med. Marko Wilke
Facharzt für Kinder- und Jugendmedizin
Leiter, Experimentelle Pädiatrische Neurobildgebung
Universitäts-Kinderklinik
Abt. III (Neuropädiatrie)
Marko Wilke, MD, PhD
Pediatrician
Head, Experimental Pediatric Neuroimaging
University Children's Hospital
Dept. III (Pediatric Neurology)
Hoppe-Seyler-Str. 1
D - 72076 Tübingen, Germany
Tel. +49 7071 29-83416
Fax +49 7071 29-5473
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http://www.medizin.uni-tuebingen.de/kinder/epn/
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