The Inventory IOD supports the recording of available access mechanisms for each repository stored instance - DIMSE Query/Retrieve (Annex C “Query/Retrieve Service Class (Normative)” in PS3.4), web services-based Studies Service (Section 10 “Studies Service and Resources” in PS3.18), and perhaps multiple non-DICOM direct file access protocols (Annex P “Stored File Access Through Non-DICOM Protocols (Normative)” in PS3.3). Either the access point for DIMSE (AE Title) or web (origin server address), or both, must be provided for each stored SOP Instance; the non-DICOM protocols are optional. See Section YYYY.7.2 for discussion of using non-DICOM protocols

Many repository applications do not keep the stored SOP Instances updated with metadata that may change over time (e.g., patient name and ID). Applications that use direct file access are required to use the current correct metadata, as recorded in the Inventory SOP Instance, rather than the metadata in the stored files (see Section YYYY.7.9).