appropriate reading/derivation of bvalues and bvectors in the dicom readers

[satra]

@matthew-brett in the data set i have shared with you, the dicom reader fails to return appropriate bvalues and bvectors. i will post a link here once that data set is made publicly available either on xnat or on midas.

[effigies]

@satra Any chance you know/can determine if this is resolved? Or possibly this is related to @mgxd's #727?

[satra]

i would close this. too old at this point and pydicom has come a long way. let's focus on #727 as a real issue.