The values of Return Key Attributes to be retrieved with the Worklist are specified with zero-length (universal matching) in the C-FIND request. SCPs shall support Return Key Attributes defined by a Worklist Information Model according to the Data Element Type (1, 1C, 2, 2C, 3) as defined in PS 3.5.
Every Matching Key Attribute shall also be considered as a Return Key Attribute. Therefore the C-FIND response shall contain in addition to the values of the requested Return Key Attributes the values of the requested Matching Key Attributes.
Notes: 1 The Conformance Statement of the SCP lists the Return Key Attributes of Type 3, which are supported.
2. An SCU may choose to supply any subset of Return Key Attributes.
3. An SCU can not expect to receive any Type 3 Return Key Attributes.
4. Return Key attributes with VR of SQ may be specified either with zero-length or with the zero-length item in the sequence.