Sort and Rename dicom files without losing dicominfo

Hi all,

I have got several sets of dicom images i'm trying to order and rename. I have written a fine working algorithm, but unfortunately i doesn't work when i'm implementing dicominfo in the dicomwrite line. I need to use the SliceThickness and PixelSpacing later on, so i need to store this info. Can anybody explain why --> dicomwrite(A,(fname), info); doesn't work. And does anybody has a suggestion about the way to implement this?

if true
  % uiwait(msgbox('Select directory to load files'))
fpath = uigetdir; 
fstruct = dir('fpath\*.dcm');
dicomlist = dir(fullfile(fpath,fstruct','*.dcm'));
uiwait(msgbox('Select directory to save files'))
fpath1 = uigetdir;
cd(fpath1);
hWaitBar = waitbar(0,'Renaming DICOM files');
for i=length(dicomlist):-1:1;
  A = dicomread(fullfile(fpath,fstruct,dicomlist(i).name));
  info = dicominfo(fullfile(fpath,fstruct,dicomlist(i).name));
  B = info.InstanceNumber;
  if  B <= 9;
      fname = ['ADNI_MRI_00', num2str(B), '.dcm'];
  elseif B <= 99;
      fname = ['ADNI_MRI_0' num2str(B), '.dcm'];
  else 
      fname = ['ADNI_MRI_', num2str(B), '.dcm'];
  end
  dicomwrite(A,(fname));
  waitbar((length(dicomlist)-i)/length(dicomlist))
end
delete(hWaitBar)
end