Working with Context Groups

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

A set of related Coded Concepts forms a Context Group. PS 3.16 of the DICOM Standard specifies the DICOM Content Mapping Resource (DCMR), which defines specific Context Groups. These Context Groups 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 class members for working with the Context Group Table. The DicomContextGroupTable class offers these members.

Initially, the Context Group Table is empty. Two ways are provided 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 DicomContextGroupTable.Load method.

By inserting Context Groups directly to the Context Group Table using the DicomContextGroupTable.Insert method.

You can use the following methods to maneuver through the Context Groups in the Context Group Table:

DicomContextGroupTable.GetFirst

DicomContextGroupTable.GetLast

DicomContextGroupTable.GetNext

DicomContextGroupTable.GetPrevious

You can also use the DicomContextGroupTable.Count property and the DicomContextGroupTable.FindIndex method to enumerate the Context Groups in the Context Group Table.

Use the DicomContextGroupTable.Find method to search the Context Group Table for the Context Group with a particular Context ID.

Use the DicomContextGroupTable.Delete method to remove individual Context Groups from the Context Group Table, and the DicomContextGroupTable.Reset method to remove all the Context Groups at once.

You can use the following methods to investigate the Coded Concepts of a Context Group:

DicomContextGroupTable.GetFirstCodedConcept

DicomContextGroupTable.GetLastCodedConcept

DicomContextGroupTable.GetNextCodedConcept

DicomContextGroupTable.GetPreviousCodedConcept

DicomContextGroupTable.GetCodedConceptCount

DicomContextGroupTable.FindCodedConceptByIndex

DicomContextGroupTable.GetContextGroup

Use the DicomContextGroupTable.FindCodedConcept method to search a Context Group in the Context Group Table for the Coded Concept with specific Coding Scheme Designator and Code Value.

After a Context Group has been added to the Context Group Table, you can modify the Code Meanings of its Coded Concepts, add new Coded Concepts to the Context Group, and delete existing Coded Concepts from the Context Group by using the following methods:

DicomContextGroupTable.SetCodeMeaning

DicomContextGroupTable.InsertCodedConcept

DicomContextGroupTable.DeleteCodedConcept

If a Context Group in the Context Group Table has a corresponding Context Group in the internal table maintained by LEADTOOLS, you can use the DicomContextGroupTable.Default method to discard any changes made to the Context Group in the Context Group Table. Use the DicomContextGroupTable.Exists or DicomContextGroupTable.ExistsCodedConcept methods to determine whether a Context Group object or a Coded Concept object is valid, respectively.