DICOM PS3.3 2021e - Information Object Definitions

F.2.2 Example of A Directory

The example provided in this Section is only one simple example of a possible directory content and organization. This Section is not normative in nature. Therefore, this example is not meant to specify a conformant directory nor to restrict the range of possible directory organizations supported by this Part of the DICOM Standard.

The overall organization is illustrated at a logical level in Section F.2.2.1. The actual structure of the content is discussed in Section F.2.2.2. Annex A “Example of DICOMDIR File Content (Informative)” in PS3.10 depicts further details of the encoding of the file content.

F.2.2.1 Illustration of the Overall Directory Organization

A simple directory content is used as an example of Directory organization. It is depicted by Figure F.2-2. The left hand side part of Figure F.2-2 depicts the various Objects stored in Files of the File-set. The right hand side presents an example of organization of the directory that facilitates access to the Files of the File-set.

This example shows how stored Files are referenced by Directory Records that are grouped into Directory Entities. The two Study Directory Records (Study 1 and Study 2) are part of the Directory Entity relative to the Patient A.

Thin curved lines depict the referencing mechanism based on File IDs that allow reference to Files containing stored objects. Thick curved lines depict the internal referencing mechanisms that support the reference to a lower-level Directory Entity by a Directory Record.

Keys that are used to select a specific Directory Record from among the Directory Records of a Directory Entity are not shown on Figure F.2-2.

One may note in this example that certain Directory Records such as the Series Directory Records do not reference Files containing stored objects. Other Directory Records such as the Image Directory Records do not reference lower level Directory Entities. However, a number of Directory Records reference both one lower level Directory Entity and one File containing a stored object. This flexibility allows the definition of a variety of directories.

Example of a Directory Organization and Content

Figure F.2-2. Example of a Directory Organization and Content

DICOM PS3.3 2021e - Information Object Definitions