Fdt diffusion analysis
For CBU data.
These are just notes of work in progress by MatthewBrett.
FDT documentation: http://www.fmrib.ox.ac.uk/fsl/fdt/index.html
FDT FAQ entries: http://www.fmrib.ox.ac.uk/fslfaq/#title_fdt
Extracting the bvals, bvecs values from Siemens data
See: http://wiki.na-mic.org/Wiki/index.php/NAMIC_Wiki:DTI:DICOM_for_DWI_and_DTI
Note that the B gradient=0 has no direction information.
So, for the example dataset I have been playing with, you can fetch the diffusion directions from the DICOM headers, by getting the DICOM file names from a diffusion dataset into the matlab string matrix input_files, and doing something like:
hdr = spm_dicom_headers(input_files);
n = length(hdr);
bvals = zeros(n, 1);
bvecs = zeros(n, 3);
for i = 1:n
H = hdr{i};
bvals(i) = str2num(H.CSAImageHeaderInfo(7).item(1).val);
if bvals(i) == 0 % no gradient
continue
end
d_info = H.CSAImageHeaderInfo(22).item;
for D = 1:3
bvecs(i,D)= str2num(d_info(D).val);
end
end