This issue came up with some GE DWI scans, where the DiffusionBValue was present when B was greater than zero, but was absent when B was equal to zero. So querying a DWI scan with "-k DiffusionBValue=0" returned nothing, making it impossible (or at least difficult) to extract the B0 images from the scan.
Likewise, there isn't any way to query whether an attribute is empty.
This issue came up with some GE DWI scans, where the DiffusionBValue was present when B was greater than zero, but was absent when B was equal to zero. So querying a DWI scan with "-k DiffusionBValue=0" returned nothing, making it impossible (or at least difficult) to extract the B0 images from the scan.
Likewise, there isn't any way to query whether an attribute is empty.