Working with Context Groups

The use of Coded Concepts in DICOM facilitates unambiguous communication of concepts or terms. Coded Concepts are incorporated in IODs using Code Sequence Attributes as described in PS 3.3 of the DICOM Standard.

A set of related Coded Concepts forms a Context Group. The Context Groups defined by the DICOM Content Mapping Resource (DCMR) (which is specified by PS 3.16 of the DICOM Standard) are maintained by LEADTOOLS in an internal table. We will refer to this table as the Context Group Table. For a list of the Context Identifiers (CIDs) of these Context Groups, along with their names, refer to Context Identifier Values.

LEADTOOLS provides a number of functions for working with a table of Context Groups. Most of these functions are named like L_DicomxxxContextGroup or like L_DicomxxxCodedConcept.

Initially, the Context Group Table is empty. LEADTOOLS provides two ways to add Context Groups to the table:

• By loading them from the internal table into the Context Group Table. This can be done using the L_DicomLoadContextGroup function.

• By inserting them directly into the Context Group Table by using the L_DicomInsertContextGroup function.

LEADTOOLS provides the following functions for maneuvering through the Context Groups in the Context Group Table:

L_DicomGetFirstContextGroup

L_DicomGetLastContextGroup

L_DicomGetNextContextGroup

L_DicomGetPrevContextGroup

You can also use the L_DicomGetCountContextGroup and L_DicomFindIndexContextGroup functions to enumerate the Context Groups in the Context Group Table.

Use the L_DicomFindContextGroup function to search the Context Group Table for the Context Group with a particular Context ID.

Use the L_DicomDeleteContextGroup function to remove individual Context Groups from the Context Group Table. You can also use the L_DicomResetContextGroup function to remove all the Context Groups at once.

LEADTOOLS provides the following functions for investigating the Coded Concepts of a Context Group:

L_DicomGetFirstCodedConcept

L_DicomGetLastCodedConcept

L_DicomGetNextCodedConcept

L_DicomGetPrevCodedConcept

L_DicomGetCountCodedConcept

L_DicomFindIndexCodedConcept

L_DicomGetCodedConceptGroup

Use the L_DicomFindCodedConcept function to search the Context Groups in the Context Group Table for a specific Coding Scheme Designator and Code Value.

Use the following functions to modify, add, or delete Coded Concepts from an existing Context Group:

L_DicomSetCodedConceptCodeMeaning

L_DicomInsertCodedConcept

L_DicomDeleteCodedConcept

If a Context Group in the Context Group Table has a corresponding Context Group in the internal table maintained by LEADTOOLS, then you can use the L_DicomDefaultContextGroup function to discard any changes made to the Context Group in the Context Group Table.

Use the L_DicomExistsContextGroup or L_DicomExistsCodedConcept functions to determine whether a pointer to a Context Group structure or to a Coded Concept structure is valid, respectively.