The Inventory IOD defines an Inventory of all Studies, Series, and SOP Instances managed by a repository, or a specified subset of those Studies, Series, and SOP Instances. It includes information about the available mechanisms to access such Studies, Series, and SOP Instances, including both DICOM and non-DICOM protocols. The Inventory provides selected Patient, Procedure, and Imaging Service Request Attribute values for the inventoried Studies.

For implementation-specific reasons, a complete Inventory may need to be divided across multiple SOP Instances. The Inventory IOD allows a SOP Instance to reference other SOP Instances whose content is logically included by such reference. A complete inventory thus consists of one root SOP Instance, with a tree of references to additional SOP Instances, the content of all of which comprises the Inventory.