Hi, Emilie.
You are right, I did make a mistake. So I revise the command as following, and it did work. The previous problem has been solved.
% info=dicominfo('1.3.12.2.1107.5.2.32.35420.2018010410543453162206454');
% info.SequenceName = '*ep_b0';
dbstop if error

filenames = dir('*.dcm');
X =dicomread(filenames(1).name);
info = dicominfo(filenames(1).name);
info.SequenceName = '*ep_b0';
fname= strcat('test',num2str(1), '.dcm');
dicomwrite(X, fname ,info)
for i = 2: size(filenames,1)
X =dicomread(filenames(i).name);
info = dicominfo(filenames(i).name);
info.SequenceName = strcat('*ep_b1000#',num2str(i-1));
% fname= ['./result/',info.MediaStorageSOPInstanceUID, '.dcm'];
fname= strcat('test',num2str(i), '.dcm');
dicomwrite(X, fname ,info)
end

but then there's only one problem remaining, which is
 command line: dke DKEParameters.dat
Diffusional Kurtosis Estimator (DKE) version 2.6.0, February 2015
Start date and time: April 29, 2018 16:38:36
Diffusional Kurtosis Estimator (DKE) version 2.6.0
Converting input DICOM images to NIfTI... complete.
Co-registering images...
Error using spm_hist2
Wrong number of dims (1).

Error in spm_coreg>optfun (line 165)
Error in spm_coreg (line 88)
Error in spm_powell (line 27)
Error in spm_coreg (line 143)
Error in dke_preprocess_dicom>coregister (line 207)
Error in dke_preprocess_dicom (line 78)
Reading input images... Error using dke_estimate (line 165)
Input NIfTI image F:\P10\intermediate_processing\combined\rdki does not exist!
Error in dke (line 182)

[color=#000000]So I think this is the only problem that is left. Do you have any clues about it?[/color]
[color=#000000]Best regards,[/color]
[color=#000000]Xinman
[/color]