Markus -
Does one of your images have only small numbers?
(i.e. are all your ADC values small).
If so this is a known bug (or characteristic) of FAST.
It thresholds the images on absolute values, not relative ones.
Try multiplying your ADC map by a large number before you start.
avwmaths ADC -mul 1000000 ADC2
and then run FAST on ADC2.
cheers
T
On Tue, 19 Feb 2002, Markus Weiger wrote:
> I used two 3D input images to do a FAST segmentation with two classes
> (CSF and brain matter). The input images were 1) a T2-image after BET
> and 2) an ADC-map with the same BET mask. This is the input:
>
> mfast -s 2 -c 2 -os -od adc_t2 t2.hdr adc.hdr
>
> The resulting error is:
>
> Empty input image. Nothing to do!
>
> even though the images were definitely not identical zero.
> The only reason for that I can imagine is that in the ADC map
> there are some pixels identical zero which have a non-zero value
> in the T2 image. May that be the problem?
>
> Markus
>
--
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Tim Behrens
Centre for Functional MRI of the Brain
The John Radcliffe Hospital
Headley Way Oxford OX3 9DU
Oxford University
Mobile 07980 884537
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