jaymeemurdoch
commented
2 years ago ValueSet Development and Analysis
Imaging Modality Category ValueSet:
Design approach: An analysis was undertaken of the DICOM Acquisition Modality codes, including generating a hierarchy to understand which concepts would group or categorise other concepts. An analysis was also undertaken of SNOMED CT imaging related concepts, including analysis of all parent/child relationships, to determine the common categories of concepts. Top level/category type concepts were obtained and cross referenced with available imaging modality categories frequently referred to in literature (no published terminology set is currently available for imaging categorisation). Analysis was then undertaken to determine whether the majority of codes contained in the proposed SNOMED CT Imaging Acquisition Modality set (outlined below) could be successfully categorised.
Considerations:
- Inclusion of a code to capture modalities that do not fit under the proposed categories requires consideration. Options include:
- A general category of 363679005|Imaging (procedure), which allows any modalities that do not fit under a specific category to be correctly categorised as an imaging procedure. This is particularly useful when considering categorisation will also be relevant for things other than imaging procedures, and ensures that this 'general' concept still provides relevant meaning and value in this category field. In this circumstance, the meaning of the category is still clear (although broad), when comparing to the use of a code like 'other'. There is the potential that a general category of |Imaging (procedure)| could be misused, where modalities that could be correctly categorised are placed under 'Imaging'.
- The the inclusion of a code of 'other' (SNOMED CT qualifier concept), which could represent modalities that do not fit into the listed specific categories. This does prove problematic in that 'other' does not have any link or meaning with relation to an imaging modality or procedure, and may prove ambiguous when viewing category in the broader sense.
TEAM DISCUSSION: It was discussed and agreed that the use of |Imaging (procedure)| is preferred over the use of |Other|. A code of Imaging will provide context to the category, while representing a general or broad category. The use of Other introduces some ambiguity as the code itself is not a modality, and has no reference to imaging or imaging modality. The use of Other also introduces issues in that the meaning of this category would change if additional categories were to be added.
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How will multi-modality procedures be categorised? Multi-modality procedures will be categorised using the same method as outlined above - either under |Imaging (procedure)| or a code to represent 'other'. This will allow for any existing or future permutation to be accounted for without the ValueSet requiring amendment.
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ConceptMaps suggested between new Imaging Modality Category ValueSet and DICOM Acquisition Modality given DICOM is bound in ImagingStudy as extensible.
| Proposed composition: SCT ID | Preferred Term | Comment |
|---|---|---|
| 363680008 | X-ray | |
| 77477000 | Computerised axial tomography | Although CT is a type of x-ray, it is very commonly referred to as a separate modality category. Guidance on the use of this ValueSet should include direction to choose the most appropriate or specific category where possible. |
| 44491008 | Fluoroscopy | As with CT, although fluoroscopy is a type of x-ray, it is very commonly referred to as a separate modality category. As above regarding guidance. |
| 373205008 | Nuclear medicine imaging | |
| 113091000 | Magnetic resonance imaging | |
| 16310003 | Ultrasound | |
| 423827005 | Endoscopy | |
| 169283005 | Medical photography | |
| 117259009 | Microscopy | |
| 363679005 | Imaging | As discussed above, a general concept to enable accurate categorisation of imaging modalities that do not fit within the above described categories. Guidance should be considered so that users are encouraged to select a more fine grained category if applicable, and only to use Imaging if no other category is applicable. |
Imaging Acquisition Modality ValueSet:
Design approach: A review was undertaken of the SNOMED CT imaging and inspection hierarchies to determine appropriate concepts for inclusion. This included a review of all children of 363679005|Imaging (procedure) and 32750006|Inspection (procedure), including an analysis of the parents and children of each concept, to obtain comprehensive list of imaging modalities. This list was cross-referenced against DICOM Acquisition Modality to ensure all relevant modalities were included. Any missing SNOMED CT codes were then added.
The proposed SNOMED CT set is more comprehensive and representative of imaging modalities used in practice. In addition to the modalities included in the DICOM set, the SNOMED CT set includes modality subtypes and variants to enable accurate recording of the modality utilised. For example, while the DICOM set includes only three types of ultrasounds; Ultrasound; Ultrasound Bone Densinometry; Intravascular Ultrasound; the SNOMED CT set includes additional subtypes or variants.
To consider:
- DICOM Acquisition Modality is bound as extensible to ImagingStudy.modality.
- ConceptMaps will be required between new Imaging Acquisition Modality ValueSet and DICOM Acquisition Modality to enable utilisation given binding of DICOM set in ImagingStudy. As DICOM is currently the standard of use in the industry, maps to/from LOINC and RadLex sets will not be considered unless stakeholder feedback deems it necessary.
Proposed composition: See Imaging Modality ValueSet wiki page for list of codes.
dtr-agency
davidmckillop
The issue / feature
Change description
To support the exchange of diagnostic reports, terminology sets are required to enable:
What it actually enables people to do
Categorisation: A ValueSet representing high level modality concepts would enable categorisation to support aggregation and discovery of imaging intensive diagnostic reports based on modality. It may be used for indexing, reporting or searching diagnostic reports based on relevant subtypes of a modality category.
Clinical concept of modality: A ValueSet representing available imaging modalities would enable accurate recording of the modality used to perform a diagnostic imaging procedure. This is important in providing context to the clinical information captured relating to the procedure, making it clear what type of diagnostic image or report is available.
How awesome would it be?
No published terminology is currently available to represent high level imaging modalities that could be utilised for diagnostic report categorisation. The DICOM Acquisition Modality set is not suitable for categorisation as it includes too broad of a set of modalities to be able to group or categorise modalities in a meaningful way.
Initial stakeholder feedback indicates that the current Acquisition Modality set published by DICOM (and currently in use) is outdated, and does not accurately reflect all modalities recorded in clinical practice. Additionally, it is preferred that content is based on SNOMED CT concepts as outlined above.
Potential benefits of accurate capture of imaging modality and modality category include reporting capability, indexing to assist image or report discoverability and preventing duplicate or unnecessary repeat imaging.
SNOMED CT concepts should be utilised moving forward as it is the Agency's preferred national clinical terminology. Additionally, SNOMED CT is the preferred national solution for clinical terminology endorsed by the Australian Health Ministers' Advisory Council (AHMAC). In recent workshops with RANZCR, SNOMED CT was identified as the preferred terminology to support diagnostic imaging.
Workarounds
The DICOM Acquisition Modality set may be utilised, though initial stakeholder feedback suggests that this set is outdated.
Additional context
There is consideration for the high level modality ValueSet for categorisation to be bound to DiagnosticReport.Category (a slice of category to indicate categorisation based on imaging modality, where binding strength may be preferred and cardinality optional).
Assessment of DICOM Acquisition Modality set The DICOM Acquisition Modality set is limited in its ability to accurate record specific subtypes of imaging modality. For example, it provides the option to record endoscopy only, rather than endoscopy or gastroscopy. Feedback from SMEs noted that the set is generally outdated and not sufficient for accurate clinical use. Feedback from DICOM stated "modality embeds the preference of the small group of experts proposing extensions to the standard" and as such, there are some groups of concepts that are quite specific (ie ophthalmic related modalities) but this is not represented across the board. As such, although the DICOM set is currently in use, the set of codes available for selection of clinical modality could be improved by making them more comprehensive and specific. This is then reflective of the available subtypes of modality and provides clinicians with the option of more accurately recording the imaging modality.
HL7 use of DICOM Acquisition Modality codes There are no existing ValueSets in use by the Agency representing imaging modality. The DICOM Acquisition Modality set is currently used by HL7, bound as extensible to ImagingStudy.modality. Although this set is currently bound to ImagingStudy.modality, the proposed new ValueSet to capture the clinical concept of modality, which is more comprehensive and clinically complete, has value in systems already utilising SNOMED CT, non-FHIR systems and to allow implementers to send both SNOMED CT and DICOM codes if desired. A concept map between DICOM Acquisition Modality and the proposed new ValueSet will be required to support this.
In R5, HL7 has bound ImagingModality which includes both DICOM Acquisition Modality and DICOM Non-Acquisition Modality, rather than just Acquisition Modality as in R4. The inclusion of equivalent non-acquisition modality codes in the SNOMED CT set was considered, however given they do not represent the modality utilised in an imaging procedure it was concluded that they have no value in the new ValueSet being proposed. Examples of such codes included: Document; Hard Copy; Key Object Selection; Plan; Registration.
Comparable existing Imaging Modality Categories Note: no defined sets found, only common groupings or categories of imaging procedures.
Medicare diagnostic imaging item categories: Ultrasounds; Computed Tomography; Diagnostic radiology (including x-ray); Nuclear medicine (including PET); Management of bulk-billed services.
DOH Diagnostic imaging, scans and X-rays: radiation (x-rays including mammography; CT scans; PET scans; nuclear medicine), sound waves (ultrasound), magnetic fields and radio waves (MRIs).
Ausmed - Medical Imaging Types and Modalities: CT, MRI, Ultrasound, X-ray, Nuclear medicine imaging (including PET).
Comparable existing Imaging Modality terminology • DICOM Acquisition Modality identifies codes that may be used to identify the type of diagnostic equipment, function or technique used to create the imaging instance. Codes are used in Attribute Modality (0008,0060).
LOINC Imaging Modality may be used for image-guided procedures, where the particular type of imaging used is not specified in the orderable. Could not see a defined set of codes, however there are codes tagged with the LOINC part {Imaging Modality} 262710-9.
RadLex Modality identifies the modality of a radiologic procedure. Multi-modality procedures are pre-coordinated rather than listing multiple modality attributes. Modality_Modifier attribute can be used to describe specialised subtype modalities ie CT angiography. Modifier set is quite small and succinct: CT, mammography, MR, NM, NM&CT, OT, PT&CT, radio-fluoroscopy, radiology procedure, ultrasound, US&FL, US&RF, XA, XR, XR&RF. RadLex Imaging Modality hierarchy also found. It contains combined modalities for PET-CT, PET-MR, SPECT-CT, US-RF, XR-RF.