Phase encoding information

I have 1 reverse phase encoding volume and a series of multi shell DKI data. I need to perform distortion correction but I can’t find information about PE direction in the header. How can I do ?

At the moment, we’re only able to get this information for Siemens DICOM data, so most users will need to provide that information to dwipreproc manually – which you can do using the -pe_dir option.