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Should I map Modality values to SOP Class UIDs?

Is it reliable to map modalities to SOPClassUIDs? In other words, does a one-one mapping for SOPClassUID to modality is fine?

Solution

  • No, a one-to-one mapping is not possible. Consider this common example where 4 SOP Class UIDs all map to 'US':

    1.2.840.10008.5.1.4.1.1.6    Ultrasound Image Storage (Retired)
1.2.840.10008.5.1.4.1.1.6.1  Ultrasound Image Storage
1.2.840.10008.5.1.4.1.1.3    Ultrasound Multi-frame Image Storage (Retired)
1.2.840.10008.5.1.4.1.1.3.1  Ultrasound Multi-frame Image Storage

    If you had an object for each one of the SOP Class UIDs shown above, they would all have 'US' in the modality tag.

    So if you just look at 'US' in modality tag 0008,0060, is it a single-frame or multi-frame echo image? It is better to consider the SOP Class UID for precisely defining the type of DICOM object you are dealing with.

    Reference: see "Annex A Registry of DICOM unique identifiers (UID)" of Part 6 of the standard.