DICOM PS3.4 2020c - Service Class Specifications

C.3.5 New Instance Creation for Enhanced Multi-Frame Image Conversion

When Query/Retrieve View (0008,0053) is present with a value of "CLASSIC" or "ENHANCED" in a C-FIND, C-MOVE or C-GET Request Identifier, then the Information Model against which the query or retrieval is performed and any SOP Instances that are retrieved shall be returned, constructed or converted according to the requirements in this section.

There are no requirements with respect to when such instances are actually created or persisted, only that they be available on request. I.e., they may be created in advance (cached) or they may be created dynamically as required, as long as the process is deterministic in the sense that the same Attributes will be populated with the same values on successive queries and retrievals (including UIDs).


  1. The UID generation process is required to be deterministic but it is important to remember that appending a suffix to an existing UID is not a valid approach to generating a new UID, unless the converter is the producer (owner of the root) of the original UID and knows that this is safe and the result will be unique.

  2. The cross-references between original and converted instances contain sufficient information to recover UIDs in the alternative form.

All instances for a Patient known to the SCP shall be converted as necessary to maintain referential integrity and to avoid information loss.


  1. It is not permitted to fail to include a subset of instances within this scope, for example, the presentation states or key object selection documents, in the "ENHANCED" view, in order to avoid the effort of creating new instances with updated references required to maintain referential integrity. In other words, the total "information content" of any view will be no less than that of the default view.

  2. This does not mean that all instances need to be converted, since if they contain no such references, they can be left alone and included in the view. For example, a Classic single slice CT localizer image with no references can remain unchanged in the view as a CT Image Storage SOP Class with its existing SOP Instance UID and SOP Class and in its existing Series, and be referenced from converted instances, such as the axial images prescribed from it. An SCU cannot make any assumptions about what will or will not be converted, or in what order.

  3. It is understood that the requirements of this section are applicable to a single SCP; it is not possible to require all SCPs that perform conversion to perform it the same way, or create the same UIDs, etc.

In addition to the general requirements in this section, specific requirements apply to the following types of instance created:

The general requirements are that:

The specific requirements for the conversion of single frame images to Enhanced Multi-frame images are:

The specific requirements for the conversion of Enhanced Multi-frame images to Classic single frame images are:

The specific requirements for the conversion of other instances are:

Table C.3.5-1. Modality-Specific SOP Class Conversions


True Enhanced

Legacy Converted Enhanced

CT Image Storage

Enhanced CT Image Storage

Legacy Converted Enhanced CT Image Storage

MR Image Storage

Enhanced MR Image Storage

Legacy Converted Enhanced MR Image Storage

PET Image Storage

Enhanced PET Image Storage

Legacy Converted Enhanced PET Image Storage

DICOM PS3.4 2020c - Service Class Specifications