F.2.2.2 Example of a DICOMDIR File Structure

Based on the example discussed in Section F.2.2.1, the internal data structure used by the Basic Directory IOD is depicted in Figure F.2-3. It shows a set of Directory Records where each Directory Record is linked by three different types of "referencing" mechanisms:

a. The chaining of Directory Records to form a Directory Entity. In particular, this facilitates the addition of new Directory Records at the level of any Directory Entity by placing them at the end of the DICOMDIR File. On Figure F.2-3, these chainings are shown by dotted lines:

1. #1 shows the chaining of the Directory Records forming the root Directory Entity

2. #2 shows the chaining of the Directory Records for the Directory Entity related to Patient A

3. #3 shows the chaining of the Directory Records for the Directory Entity related to Study 1

4. #4 shows the chaining of the Directory Records for the Directory Entity related to Series 1

b. Thick curved lines depict the reference by a Directory Record to a lower level Directory Entity

c. Thin curved lines depict the reference by a Directory Record to a stored file containing a SOP Class

This example of a DICOMDIR File structure shows one example of a specific order of the Directory Records. Other orderings of Directory Records could result in a functionally equivalent directory.

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Figure F.2-3EXAMPLE OF DATA STRUCTURE FOR THE DICOM DIRECTORY INFORMATION