DICOM PS3.1 2019c - Introduction and Overview

3 Definitions

Attribute

A property of an Information Object. An Attribute has a name and a value that are independent of any encoding scheme.

Command

A request to operate on information across a network.

Command Element

An encoding of a parameter of a command that conveys this parameter's value.

Command Stream

The result of encoding a set of DICOM Command Elements using the DICOM encoding scheme.

Conformance Statement

A formal statement that describes a specific implementation of the DICOM Standard. It specifies the Service Classes, Information Objects, Communication Protocols, Security Profiles, and Media Storage Application Profiles supported by the implementation.

Data Dictionary

A registry of DICOM Data Elements that assigns a unique tag, a name, value characteristics, and semantics to each Data Element.

Data Element

A unit of information as defined by a single entry in the data dictionary.

Data Set

Exchanged information consisting of a structured set of Attributes. The value of each Attribute in a Data Set is expressed as a Data Element.

Data Stream

The result of encoding a Data Set using the DICOM encoding scheme (Data Element Numbers and representations as specified by the Data Dictionary).

Information Object

An abstraction of a real information entity (e.g., CT Image, Structured Report, etc.) that is acted upon by one or more DICOM Commands.

Note

This term is primarily used in PS3.1, with a few references in PS3.3. It is an informal term corresponding to a formal term that is introduced in PS3.3. In all other parts of the DICOM Standard this formal term is known as an Information Object Definition.

Information Object Class

A formal description of an Information Object, which includes a description of its purpose and the Attributes it possesses. It does not include values for these attributes.

Note

This term is only used in PS3.1. It is an informal term corresponding to a formal term that is introduced in PS3.4. This formal term is known as a Service-Object Pair Class or more commonly as a SOP Class.

Information Object Instance

A representation of an occurrence of an real-world entity, which includes values for the Attributes of the Information Object Class to which the entity belongs.

Note

This term is only used in PS3.1. It is an informal term corresponding to a formal term that is introduced in PS3.4. This formal term is known as a Service-Object Pair Instance or more commonly as a SOP Instance.

Message

A data unit of the Message Exchange Protocol exchanged between two cooperating DICOM Applications. A Message is composed of a Command Stream followed by an optional Data Stream.

Part

Subdivision of the DICOM Standard that covers related subject material.

Service Class

A structured description of a service that is supported by cooperating DICOM Applications using specific DICOM Commands acting on a specific class of Information Object.

Service-Object Pair Class (SOP Class)

The pair of an Information Object and either a DIMSE Service Group, a Media Storage Service, or a Web Service.

DICOM PS3.1 2019c - Introduction and Overview