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Hi Michael,

You were right, it was not specific to ASL and I have fixed the problem.

I want to use Melodic because I'm more interested in functional
connectivity differences between groups rather than functional activation
increases and decreases.

To test for group differences, can I run dual_regression as one does
usually for resting-state fMRI?

Are the resting ASL networks the same than the resting fMRI networks? Can I
use Biswal's metaICA to identify them using fslcc?

Thanks!


2013/4/21 Michael Chappell <[log in to unmask]>

> I cannot immediately see why that has failed, it doesn't look like
> something specific to ASL.However, I don't have a lot of experience of ASL
> with melodic - what are you trying to do that means you want to use melodic?
>
> Michael
>
> On 18 Apr 2013, at 14:26, maria estanqueiro <[log in to unmask]>
> wrote:
>
> Dear Michael,
>
> I also have resting-state pseudocontinous ASL data, which I was trying to
> analyze with Melodic by selecting the Perfusion subtraction option and
> Multiple concatenation approach.
>
> I am very new to ASL preprocessing and have no idea whether I need to
> change any other options in the Melodic interface.
>
> The error I show bellow came out. I checked in mi reg_standard/ folders
> and in fact no filtered_func_data were generated. I tried using
> featregapply my_directory -f and it didn't work either.
>
> Do you know how to solve this?
>
>
> Higher-level MELODIC
>
> /maxim/software/fsl5/fsl/bin/featregapply
> /maxim/home/maria/FINAL/AD/1002/ASL/20100518_170013000001ep2dpcaslphys1002570425-1122s004a001_ASL.ica
>
> /maxim/software/fsl5/fsl/bin/flirt -ref reg/standard -in reg/standard -out
> reg_standard/standard -applyisoxfm 4
>
>
> /maxim/software/fsl5/fsl/bin/flirt -ref reg_standard/standard -in
> filtered_func_data -out frgrot_3IOVng -applyxfm -init
> reg/example_func2standard.mat -interp trilinear -datatype float
> Image Exception : #22 :: ERROR: Could not open image filtered_func_data
> terminate called after throwing an instance of 'RBD_COMMON::BaseException'
>
> /maxim/software/fsl5/fsl/bin/fslmaths reg_standard/filtered_func_data
> -Tstd -bin reg_standard/mask -odt char
> Cannot open volume reg_standard/filtered_func_data for reading!
>
>
>
>
>
> 2013/4/18 Bhaswati Roy <[log in to unmask]>
>
>> Thank You so much for your help.
>>
>>
>> On Thu, Apr 18, 2013 at 4:38 PM, Michael Chappell <
>> [log in to unmask]> wrote:
>>
>>> If you want to do a simple t-test between the two groups then you should
>>> be able to use FEAT and do a 'higher-level' analysis testing your CBF maps
>>> as the parameter estimates. This would then be the same procedure as a BOLD
>>> higher level analysis so you can consult that section of the help pages.
>>> Alternatively you can use the non-parametric method in randomise for the
>>> same job.
>>> You might like to determine if the CBF images you are getting from your
>>> scanner are in absolute or relative units. If the latter then there could
>>> be some extra global scaling between individuals that is not purely
>>> perfusion differences.
>>>
>>> Michael
>>>
>>> On 15 Apr 2013, at 10:07, Bhaswati Roy <[log in to unmask]> wrote:
>>>
>>> > Dear Sir,
>>> >
>>> > We have obtained CBF maps derived from 3D pseudocontinous ASL imaging
>>> from 20 controls and 20 patients. CBF maps are generated from the scanner
>>> itself. We want to generate maps showing regions where CBF values are
>>> different of patients than control. I am very much confused as to use which
>>> FSL tool for generating these maps.
>>> >
>>> > Thanks in advance
>>> >
>>> > Regards
>>> > Bhaswati
>>>
>>
>>
>
>