mALFF-1

Submitted by mghasemi on Wed, 02/24/2010 - 22:07

Dear All
Hi,
1- Why we should use mALFF-1 images for one sample t-test? why we can't use mALFF or ALFF images?
2- When I run 'Image calculator' in REST and add 20 mALFF images as group images and expression was "g1-1". The below error occured in matlab workspace:
??? Error using ==> horzcat
CAT arguments dimensions are not consistent.

Error in ==> rest_WriteAnalyzeImage at 79
fwrite(fid,[0,vsize],'float32');

Error in ==> rest_writefile at 84
    rest_WriteAnalyzeImage(data,filename,isize,vsize,Header.Origin,dtype);

Error in ==> rest_ImgCal_gui>img_cal at 431
        rest_writefile(Y,outname,size(g1),voxdim,header,'double') ;

Error in ==> rest_ImgCal_gui>btnCompute_Callback at 158
    img_cal(OutDir,OutPut,Function,Gmag,data);

Error in ==> gui_mainfcn at 96
        feval(varargin{:});

Error in ==> rest_ImgCal_gui at 26
    gui_mainfcn(gui_State, varargin{:});

??? Error while evaluating uicontrol Callback

Please guide me
thanks alot

 

Submitted by YAN Chao-Gan on Thu, 02/25/2010 - 16:48

1. For ReHo, ALFF and fALFF maps, the one-sample t-tests were to find regions showing significantly higher ReHo, ALFF and fALFF, respectively, than the global mean value. After being divided by the global mean value, each individual ReHo, ALFF and fALFF map has a ‘new’ global mean of ‘1’. Thus the one-sample t-tests were performed against ‘1’ other than ‘0’. Since the module for one-sample t test in SPM just can compare values with base "0", we subtracted "1" from the ReHo, ALFF and fALFF maps which had been divided by global mean value of the whole brain, and then perform one-tailed one-sample t-tests on the subtracted maps in SPM.
2. This is a bug of the current version of REST when performing image calculation on ANALYZE format images. Thank you very much for your report, we will fix this bug in the next release.
Currently, you can revise the last part of rest_writefile.m
FROM:
else
    if strcmp(dtype,'single')
        dtype='float';  %Revised by YAN Chao-Gan, 090420. rest_WriteAnalyzeImage.m only recognize 'float', thus change the parameter 'single' to 'float'.
    end
    rest_WriteAnalyzeImage(data,filename,isize,vsize,Header.Origin,dtype);
end

To:
else
    if strcmp(dtype,'single')
        dtype='float';  %Revised by YAN Chao-Gan, 090420. rest_WriteAnalyzeImage.m only recognize 'float', thus change the parameter 'single' to 'float'.
    end
    if strcmpi(num2str(size(vsize)),'3  1')
        vsize=vsize';   %Revised by YAN Chao-Gan, 100225. Check if vsize is a 1 by 3 array.
    end
    rest_WriteAnalyzeImage(data,filename,isize,vsize,Header.Origin,dtype);
end

Best wishes!