DICOM PS3.17 2021e - Explanatory Information

DDDD.3.2 Interpreting the Non-Standard Measurement

The characteristics of the real-world measurement measured by the acquisition system and user are conveyed in the mandatory post-coordinated descriptors recorded alongside the measurement value.

The presence of such post-coordinated descriptors aids the consumer application in

  1. Mapping the non-standard measurement to a corresponding internally-supported measurement. The full details provided by including the post-coordinated descriptors greatly simplifies the task of determining measurement equivalence.

  2. Organizing the display of the non-standard measurement values in a report. It is clinically useful to structure written reports in a hierarchical manner by displaying all measurements that pertain to the same anatomical structure or physiological condition together.

  3. Interpreting similar anatomical measurements differently depending on such characteristics as acquisition image mode (e.g., 2D vs. M-mode image). Since the clinical interpretation may depend on this information, it should be explicitly included along with the measurement concept code/code meaning.

  4. Analyzing accumulated report data (trending, data mining, and big data analytics)


Some of these benefits are reduced if the context groups specified for each post-coordinated descriptor are extended with custom codes. A user should take great care when considering the extension of the standard context groups to minimize the proliferation of modifier codes.

The first time that a consumer application encounters a new post-coordinated measurement, it will need to evaluate it based on the values of the post-coordinated descriptors. To help the consumer application with subsequent encounters with the same type of measurement, the acquisition system can consistently populate the Concept Name of the measurement with a code that corresponds to the collection of post-coordinated descriptor values; effectively a non-standard, but stable, pre-coordinated measurement code. (See TID 5302 “Post-coordinated Echo Measurement”, Row 1)

The presence of the pre-coordinated code in addition to the post-coordinated descriptors allows subsequent receipt of the same measurement to utilize the mapping that was performed as described above and treat the measurement as an effectively pre-coordinated measurement.

If the acquisition system is aware of other pre-coordinated codes (e.g., those used by other vendor carts) that are also equivalent to the collection of post-coordinated descriptor values for a given measurement, those pre-coordinated codes may be listed as (121050, DCM, "Equivalent Meaning of Concept Name"). These "known mappings" provided by the acquisition system can also be useful for consumer applications trying to recognize or map measurements.

DICOM PS3.17 2021e - Explanatory Information