IHTSDO-161 (artf231911) Radiography vs X-ray
https://projects.jira.snomed.org/browse/IHTSDO-161
SNOMED CT Content Improvement Project
Combined Inception and Elaboration phases | ||
Project ID: artf231911 IHTSDO-161 Topic: Radiography versus X-Ray
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Date | 19 September 2016 | |
Version | 1.0 Approved | |
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Amendment History
Version | Date | Editor | Comments |
0.01 | 20160531 | Maria Braithwaite | First draft for submission |
0.02 | 20160802 | Maria Braithwaite | Second draft to incorporate review feedback |
1.0 | 20160919 | Maria Braithwaite | Approved version with minor changes |
Review Timetable
Review date | Responsible owner | Comments |
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© International Health Terminology Standards Development Organisation 2016. All rights reserved.
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Table of Contents
1 Glossary............................................................................................................................................... 5
1.1 Domain Terms................................................................................................................................... 5
2 Introduction.......................................................................................................................................... 6
2.1 Purpose............................................................................................................................................ 6
2.2 Audience and stakeholder domain................................................................................................... 6
2.2.1 Input from stakeholders............................................................................................................... 6
2.2.2 Degree of consensus on the statement of problem..................................................................... 6
3 Statement of the problem or need................................................................................................... 7
3.1 Summary of problem or need, as reported....................................................................................... 7
3.2 Summary of requested solution........................................................................................................ 7
3.3 Statement of problem as understood............................................................................................... 7
3.3.1 Radiographic Procedures Example 1......................................................................................... 8
3.3.2 Radiographic Procedures Example 2......................................................................................... 8
3.3.3 Radiographic Procedures Example 3......................................................................................... 9
3.4 Detailed analysis of reported problem, including background.......................................................... 9
3.4.1 Ambiguous Grouper Concept................................................................................................... 10
3.4.2 Duplicate Synonyms................................................................................................................. 11
3.4.3 Inconsistent Use of Imaging Action.......................................................................................... 11
3.4.4 Inconsistent Naming of Procedures.......................................................................................... 13
3.4.5 Where does ‘Diagnostic’ fit in?.................................................................................................. 14
3.4.6 Plain Film................................................................................................................................. 15
3.4.7 Impact on the Clinical Finding Hierarchy................................................................................. 15
3.5 Subsidiary and interrelated problems............................................................................................. 16
3.5.1 Impact On Hierarchies Other Than Procedure......................................................................... 16
3.5.2 Undesirable Inferred Relationships........................................................................................... 16
3.5.3 Intermediate Primitive Concepts.............................................................................................. 16
3.5.4 Potential duplication................................................................................................................ 16
3.5.5 Miscellaneous Modelling Issues............................................................................................... 17
4 Risks / Benefits................................................................................................................................. 18
4.1.1 Risks of not addressing the problem.......................................................................................... 18
4.1.2 Risks of addressing the problem................................................................................................ 19
5 Requirements: criteria for success and completion................................................................. 21
5.1 Criteria for success/completion...................................................................................................... 21
5.2 Strategic and/or specific operational use cases............................................................................ 21
6 Solution Development..................................................................................................................... 22
6.1 Initial Design.................................................................................................................................... 22
6.1.1 Modelling of Imaging Action.................................................................................................... 22
6.1.2 Description Recommendation.................................................................................................. 26
6.1.3 Text Definition.......................................................................................................................... 27
6.1.4 Significant design or implementation decisions / compromises............................................... 28
6.1.5 Evaluation of Design................................................................................................................ 28
6.2 Iteration One................................................................................................................................ 28
6.2.1 Outline of Revised Design........................................................................................................ 28
6.2.2 Significant Design or Implementation Changes....................................................................... 29
6.2.3 Evaluation of Revised Design................................................................................................... 30
7 Recommendation............................................................................................................................ 32
7.1.1 Initial Detailed Design Specification........................................................................................ 32
7.1.2 Iteration Plan – Updated Detailed Design Specification.......................................................... 32
8 Quality program criteria................................................................................................................... 35
8.1 Quality metrics................................................................................................................................ 35
8.1.1 Quality metric 1........................................................................................................................ 35
8.1.2 Quality metric 2........................................................................................................................ 35
9 Project Resource Estimates.......................................................................................................... 36
9.1 Scope of construction phase......................................................................................................... 36
9.2 Projection of remaining overall project resource requirements...................................................... 36
9.2.1 Expected project resource requirement category..................................................................... 36
9.2.2 Expected project impact and benefit....................................................................................... 36
9.2.3 Indicative resource estimates for construction, transition and maintenance:............................ 36
10 Appendices..................................................................................................................................... 38
10.1 Appendix A................................................................................................................................... 38
10.2 Appendix B................................................................................................................................... 38
10.3 Appendix C................................................................................................................................... 44
10.4 Appendix D................................................................................................................................... 44
1 Glossary
1.1 Domain Terms
Radiography | “Radiography is a broad term that covers several types of studies that require the visualization of the internal parts of the body using x-ray techniques…radiography means a technique for generating and recording an x-ray pattern for the purpose of providing the user with a static image(s) after termination of the exposure…”
“Conventional radiography involves the use of x-rays; the term “plain x-rays” is sometimes used to distinguish x-rays used alone from x-rays combined with other techniques (eg, CT). For conventional radiography, an x-ray beam is generated and passed through a patient to a piece of film or a radiation detector, producing an image” |
X-ray | “X-ray technology is the oldest and most commonly used form of medical imaging. X-rays use ionizing radiation to produce images of a person’s internal structure by sending X-ray beams through the body, which are absorbed in different amounts depending on the density of the material. In addition, included as “x-ray type” devices are also mammography, interventional radiology, computed radiography, digital radiography and computed tomography (CT).”
Source: http://www.medicalimaging.org/about-mita/medical-imaging-primer/
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Plain X-ray | “…The term “plain x-rays” is sometimes used to distinguish x-rays used alone from x-rays combined with other techniques (eg, CT)…”
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2 Introduction
2.1 Purpose
The purpose and scope of this content project is to:
Review the inconsistent naming of ‘X-ray’ and ‘Radiographic imaging’ and ‘Plain X-ray’ concepts that are subtypes of 363680008|Radiographic imaging procedure (procedure) in the procedure hierarchy.
Propose a naming convention in order to improve the representation of these concepts in descriptions and facilitate the drafting of guidance for the Editorial Guide.
Review the inconsistent modelling of ‘X-ray’ and ‘Radiographic imaging’ and ‘Plain X-ray’ concepts that are subtypes of 363680008|Radiographic imaging procedure (procedure) in the procedure hierarchy.
Propose a consistent modelling approach for these concepts in order to improve representation and subsumption and remove duplication.
2.2 Audience and stakeholder domain
The audience for this document includes all standards terminology leaders, implementers and users of SNOMED CT.
A further significant audience is the community of SNOMED CT terminologists that may be requested to implement the recommended specification this includes the IHTSDO Content Team.
2.2.1 Input from stakeholders
Review of some aspects of the proposed solution was sought from a group of expert clinicians in interventional and diagnostic imaging with the assistance of a National Release Centre. Review and input was also sought from within the Consultant Terminologist community.
A review of RadLex (http://www.rsna.org) and DICOM (http://dicom.nema.org) was undertaken to gain a broader perspective of how the area of imaging that is addressed in this document is managed in other terminologies. DICOM has recently signed a collaboration agreement with IHTSDO and so a uniform approach may be of benefit.
It is noted that there are approximately 160 requests in the IHTSDO request portal (SIRS) for new concepts that will fall into the scope of this content project. These new requests are from a variety of National Release Centres and users of SIRS demonstrating that users require content in this area.
2.2.2 Degree of consensus on the statement of problem
This content project is required to address a known content issue that has been acknowledged in the Editorial Guidance, the document states:
“There is a need to differentiate a grouper for all imaging procedures that utilize X-rays, from plain X-rays. The goal for this guidance is plain X-rays of a site. Given the apparent lack of consensus, the solution probably will involve a text definition and a naming convention specific to SNOMED CT, with advice to implementers.” https://snomed.atlassian.net/wiki/display/public/EditorialGuide/7.8.1+X-ray+imaging
3 Statement of the problem or need
3.1 Summary of problem or need, as reported
There is inconsistency with naming ‘Radiology of X’ and ‘X-ray of X’ and ‘Plain X-ray of X’ and the modelling of these concepts. Some concepts use the description ‘Radiographic imaging,’ others use ‘X-ray’ or ‘Plain X-ray’ and in some concepts all of these terms are applied synonymously. In many cases the value for the method attribute does not align with the descriptions.
The SNOMED CT Editorial Guide indicates:
7.8.1 X-ray imaging
Two possible approaches have been discussed, and final resolution has not yet been reached.
Option 1:
Descriptions:
FSN: Radiography of X (procedure) PT: Radiography of X
Option 2: Descriptions:
FSN: X-ray of X (procedure) PT: X-ray of X
https://snomed.atlassian.net/wiki/display/public/EditorialGuide/7.8.1+X-ray+imaging
3.2 Summary of requested solution
The solution as suggested in the Editorial Guide is to “differentiate a grouper for all imaging procedures that utilize X-rays, from plain X-rays. Given the apparent lack of consensus, the solution probably will involve a text definition and a naming convention specific to SNOMED CT, with advice to implementers.”
https://snomed.atlassian.net/wiki/display/public/EditorialGuide/7.8.1+X-ray+imaging
3.3 Statement of problem as understood
In the international edition of SNOMED CT there is inconsistency with naming and modelling of concepts that reference Radiographic imaging, X-ray and Plain X-ray. This is a known issue, the SNOMED CT Editorial Guide states:
“6.2.5.7 Radiographic procedures
| Radiographic imaging procedure | [363680008 | Radiographic imaging procedure |] was created as the top of a hierarchy of imaging procedures utilizing x-rays. | Diagnostic radiologic examination | [38743002] had a synonym of “X-ray”, but this code has been retired because it may have been interpreted more narrowly, in particular because of the possibly narrower interpretation of radiologic versus radiographic, and the possibly narrower interpretation of diagnostic. Nevertheless, the phrase "diagnostic radiography is allowed in many of the FSNs of subtypes of | radiographic imaging procedure |.”
https://snomed.atlassian.net/wiki/display/public/EditorialGuide/6.2.5+Specific+procedure+types
The following are examples taken from the January 2016 international release of SNOMED CT:
3.3.1 Radiographic Procedures Example 1
The above example 363680008|Radiographic imaging procedure (procedure) has the Synonym ‘X-ray’ and uses the value 278110001|Radiographic imaging - action (qualifier value) for the Method attribute.
As a result of this the concept has subtypes which include 77477000|Computerized axial tomography (procedure) and 44491008|Fluoroscopy (procedure).
These descendant concepts are logical due to the method applied however the synonym appears to indicate X-ray in its broadest term i.e. an X-ray technique.
3.3.2 Radiographic Procedures Example 2
In this example 168537006|Plain radiography (procedure) has the Synonym ‘X-ray’ and is modelled with an imaging action of 312254007|Plain X-ray imaging - action (qualifier value).
This concept has both Plain X-ray and X-ray as synonyms. One term is broader than the other and it is likely that the interchangeable use of these terms is confusing to both content editors and end users.
3.3.3 Radiographic Procedures Example 3
In this final example 426945003|X-ray of bone (procedure) has both X-ray and Plain X-ray used synonymously in the descriptions. This concept does NOT currently inherit all of the descendant concepts that it should. For example:
241089007|Ilium X-ray (procedure) is NOT currently a descendant of 426945003|X-ray of bone (procedure) it is a sibling. This is because the concept is modelled with a method of 278110001|Radiographic imaging - action (qualifier value). Taking into account the descriptions, the concept was most likely intended to denote a plain X-ray procedure and therefore should be modelled with a method of 312254007|Plain X-ray imaging - action (qualifier value).
Similar examples to these above can be found throughout the hierarchy 363680008|Radiographic imaging procedure (procedure).
3.4 Detailed analysis of reported problem, including background
There may be local preferences that dictate which particular wording a clinician prefers to use. However within SNOMED CT, the fully specified name must “uniquely describe a concept and clarify its meaning…” https://snomed.atlassian.net/wiki/display/public/EditorialGuide/7.1.1+Fully+Specified+Name
In the international edition of SNOMED CT, 278110001|Radiographic imaging - action (qualifier value) acts as a grouper for other concepts in the qualifier value hierarchy as demonstrated below:
278110001|Radiographic imaging - action (qualifier value) was most probably originally intended to be used to model concepts that use x-ray imaging of some form and to subsume more granular imaging modality procedures that utilise special equipment such as a computed tomography scanner.
In reality 278110001|Radiographic imaging - action (qualifier value) has been used to model concepts that reference X-ray and the terms ‘X-ray’, ‘radiograph’, ‘radiographic imaging’ and ‘plain X-ray’ are being used synonymously across SNOMED CT as they might be in clinical practice.
The result is inconsistency that can be seen in the hierarchy 363680008|Radiographic imaging procedure (procedure). The key issues to be addressed are outlined in the sections below.
3.4.1 Ambiguous Grouper Concept
363680008|Radiographic imaging procedure (procedure) has 2801 descendant concepts at the time of the January 2016 release. In its broadest interpretation a radiographic imaging procedure “covers several types of studies that require the visualization of the internal parts of the body using x-ray techniques” http://www.fda.gov/Radiation-EmittingProducts/RadiationEmittingProductsandProcedures/MedicalImaging/MedicalX-Rays/ucm175028.htm
Arguably inclusion of the synonym ‘X-ray’ is a contravention of editorial policy because it is a narrower term that that of the FSN (see Editorial Guide Section 7.4.3 Narrower Synonyms).
https://snomed.atlassian.net/wiki/display/public/EditorialGuide/7.4.3+Narrower+synonyms
However it is acknowledged that these terms may be used widely as synonyms in clinical practice. The interchangeable nature of the terms ‘X-ray’ and ‘radiographic imaging procedure’ throughout SNOMED CT was raised with the expert group. The group expressed the opinion that these descriptions are routinely used synonymously in clinical practice in order to denote the same imaging procedure.
3.4.2 Duplicate Synonyms
The concept 168537006|Plain radiography (procedure) has a synonymous description ‘X-ray’ as does its parent concept 363680008|Radiographic imaging procedure (procedure).
‘Roentgenography’ appears on both parent (363680008|Radiographic imaging procedure (procedure)) and child (168537006|Plain radiography (procedure)). The application of the same synonym to both concepts is confusing to users and in contravention of the Editorial Guidance that stipulates
“7.4.2 Synonyms
A synonym is a term with the same meaning as another term…Addition of the same term as a synonym to more than one concept will not usually be acceptable, but of course some terms have more than one meaning…When a term can take more than one meaning, the term may be attached to multiple concepts without violating this rule. Where multiple concepts have an identical term as a synonym, a review will be undertaken to ascertain if the concepts involved are duplicates.
Where the concepts are duplicates, one concept will be retired with a SAME_AS relationship to the concept it duplicated.
Where a term with a single meaning is associated with more than one concept (which are not duplicates), the term should be retained on only one of the concepts and retired on the other(s).
In some cases a general term may be acceptable as a synonym for two or more specific concepts, depending on the context of use to derive proper specificity (e.g. "fundus" in the context of obstetrics vs ophthalmology). It is expected that these occasions will be unusual, and should be highlighted as exceptions, to assist with proper usage. Editorial guidance for broader synonyms should be taken into account.”
https://snomed.atlassian.net/wiki/display/public/EditorialGuide/7.4.2+Synonyms
3.4.3 Inconsistent Use of Imaging Action
278110001|Radiographic imaging - action (qualifier value) is a grouper concept and it is assumed it was originally intended to be a supertype for more granular imaging techniques that also utilise X-ray such as computed tomography and mammography. Where the fully specified name describes a particular imaging modality for example ‘Plain X-ray’, the granular subtype of imaging modality should be applied as the method to existing content.
In many instances 278110001|Radiographic imaging - action (qualifier value) has been used as the method for a concept that either only uses X-ray in the descriptions or uses a mix of both X-ray and radiographic imaging in the descriptions. The inappropriate use of 278110001|Radiographic imaging - action (qualifier value) has resulted in suboptimal inferred relationships across the hierarchy.
The following concepts are examples of this from the January 2016 release:
3.4.3.1 Radiography of chest wall (procedure)
Method 278110001|Radiographic imaging - action (qualifier value) and has the synonym ‘X-ray of chest wall. However, this concept is not a descendant of 399208008|Plain chest X-ray (procedure) as end users may expect. Where this concept appears in the clinical record, it is open to interpretation whether the clinician has recorded a procedure that uses X-ray of some type or whether this is a plain X-ray procedure that uses a single imaging modality of X-ray without specialist equipment or contrast media.
3.4.3.2 Soft tissue X-ray chest (procedure)
Uses the method 278110001|Radiographic imaging - action (qualifier value) and as a result the concept is not a descendant of 399208008|Plain chest X-ray (procedure).
3.4.3.3 Whole body X-ray of stillborn infant (procedure)
Uses the term ‘X-ray’ and is modelled with the method 278110001|Radiographic imaging - action (qualifier value).
3.4.4 Inconsistent Naming of Procedures
Across the hierarchy 363680008|Radiographic imaging procedure (procedure) the terms Radiograph, Radiographic Imaging, X-ray, Plain X-ray and Roentgenography are being used synonymously.
An example from the January 2016 release
This concept uses ‘X-ray’ and ‘Radiographic imaging’ synonymously however it is modelled with a method of 312254007|Plain X-ray imaging - action (qualifier value). X-ray is one type of radiographic imaging and so this synonym is more granular than the FSN. There is an approved naming convention for the addition of new content to the diagnostic imaging domain see Editorial Guide 7.8 Naming Conventions for Clinical Imaging Procedures.
The guidance document notes “There are a number of inconsistencies in existing content, but it is not required that these naming conventions necessarily be applied wholesale to that content. It is definitely intended for new content. Changes to existing content to conform to these guidelines will be considered based on value to users.”
3.4.5 Where does ‘Diagnostic’ fit in?
There are a number of concepts in the hierarchy 363680008|Radiographic imaging procedure (procedure) that explicitly use the word ‘Diagnostic’.
For example
32328007|Diagnostic radiography during operative procedure (procedure)
33450004|Diagnostic radiography with special study (procedure)
36004004|Diagnostic tomography (procedure)
There is inconsistency in the application of ‘has intent’ and diagnostic’ and the way this type of content is modelled. For example 27483000|Diagnostic radiography with contrast media (procedure) is marked as fully defined but does not use the 363703001|Has intent (attribute) in its modelling. 60654006|Diagnostic radiography of abdomen (procedure) is marked as fully defined and has the same issue.
Clinical imaging procedures may be divided into ‘diagnostic’ and ‘interventional imaging.’ Diagnostic imaging is used for the purposes of obtaining information for example 305053005|Computed tomography of aorta (procedure)|. Interventional imaging is often used for the purpose of treating a specific condition for example 431749009|Aspiration using computed tomography guidance (procedure)| or obtaining further information such as 277591006|Computed tomography guided biopsy (procedure)|.
For interventional imaging where the explicit procedure intent is guidance, this usually modelled using 363703001|Has intent (attribute) and 429892002|Guidance intent (qualifier value). This attribute and value pair are assigned as part of a relationship group and results in the concept being a descendant of 258174001|Imaging guidance procedure (procedure).
258174001|Imaging guidance procedure (procedure) is a descendant of 362961001|Procedure by intent (procedure).
There are many examples in the hierarchy 363680008|Radiographic imaging procedure (procedure) where ‘diagnostic’ is included in a fully specified name but diagnostic intent is not included in the relationship groups of the concept and this requires further evaluation. There is an existing content project Artf6232 to address the issues around the use of 363703001|Has intent (attribute) and although this is noted as an issue in this content project it is beyond the scope of the problems to be addressed as part of this content project.
3.4.6 Plain Film
The terms ‘Plain film’ and ‘Plain X-ray’ are being used synonymously in the hierarchy 363680008|Radiographic imaging procedure (procedure). The method 312254007|Plain X-ray imaging - action (qualifier value) also stipulates ‘plain.’ There does not appear to be a clinical difference between Plain X-ray and Plain film. This issue was referred to the clinical expert group for opinion who confirmed this assumption. The group also expressed the view that the inclusion of ‘plain’ is superfluous and does not align with clinical parlance. However the group also acknowledged that it is important for the terminology to make some distinction between plain X-ray and its broader interpretations.
Examples from the January 2016 release:
370142005|Plain film of head (procedure)
303938002|Plain film of neck (procedure)
The above concepts are examples of current content that is modelled with a method of 312254007|Plain X-ray imaging - action (qualifier value) however these concepts do not use the term ‘X-ray’ in any description.
This is an issue for search, retrieval of data and audit. It is also possible that this degree of inconsistency in naming will result in the addition of duplicate concepts.
3.4.7 Impact on the Clinical Finding Hierarchy
The issues with modelling in the procedure hierarchy as outlined above have had a considerable impact in the clinical finding hierarchy. In the screenshot below it is demonstrated that the concept 168541005|Plain X-ray result normal (finding) does not subsume a large number of ‘Plain X-ray of X normal (finding)’ concepts.
It is not possible to correct this issue in the Clinical finding hierarchy until the original issue in the procedure hierarchy is rectified.
3.5 Subsidiary and interrelated problems
3.5.1 Impact On Hierarchies Other Than Procedure
The issues found in the procedure hierarchy are perpetuated in the Clinical finding hierarchy as described in the section above. There are also associated problems identified in other hierarchies.
708175003|Diagnostic imaging service (qualifier value) has a descendant concept 310125001|Radiology service (qualifier value).
It is not clear if 310125001|Radiology service (qualifier value) actually means X-ray service or radiographic imaging service. If it means the latter then 310128004|Computerized tomography service (qualifier value) as an example should be a child and not a sibling concept. Also of note 708174004|Interventional radiology service (qualifier value) is a descendant of 708175003|Diagnostic imaging service (qualifier value). Interventional radiology and Diagnostic Imaging are two separate branches in the domain of clinical imaging.
The situation hierarchy has a large number of concepts that refer to unilateral imaging, for example 702005|Unilateral imaging of renal artery (situation). Unilateral content falls into scope for an existing content project artf6236, this content should be reviewed for validity.
3.5.2 Undesirable Inferred Relationships
Where possible all existing content that is a descendant of 363679005|Imaging (procedure) should be reviewed and remodelled to the closest primitive parent with the addition of relationship groups as required. This will ensure that undesirable inferred relationships are removed and optimise subsumption of existing and future content. This matter is being considered and addressed as a separate IHTSDO content project.
3.5.3 Intermediate Primitive Concepts
A number of primitive concepts (some of which are intermediate primitive concepts) have been identified during this review. It would be highly advantageous to review these concepts with the aim of making the concepts fully defined. This would allow the classifier to assign logical inferred relationships.
Examples of these concepts are:
241685002|X-ray photon absorptiometry (procedure)
22760005|Xeroradiography (procedure)
429700005|Radiopharmaceutical imaging (procedure)
442567001|Radiographic imaging of lymphatic system using contrast (procedure)
3.5.4 Potential duplication
As a result of the issues outlined with modelling approach and descriptions, once changes are made and the classifier run equivalency between concepts will be uncovered. Removal of equivalency will contribute to the overall quality of SNOMED CT.
3.5.5 Miscellaneous Modelling Issues
A number of other issues with content in the hierarchy 363679005|Imaging (procedure) have been identified during this review. Whilst these issues are outside the scope for this project, addressing them as part of an overall clean up of the hierarchy will improve the quality.
A few examples of this are:
439101006|X-ray tomography (procedure) is an intermediate primitive which could be fully defined. Is this a dual imaging modality?
Inactivate 303936003|Specific plain X-ray investigations (procedure)
Review 168731009|Standard chest X-ray (procedure) this appears to duplicate the parent concept
Inactivate 55402005|Hospital admission, for laboratory work-up, radiography, etc. (procedure)
4 Risks / Benefits
Achieving a workable solution to this content project is desirable because the concept 363680008|Radiographic imaging procedure (procedure) has 2801 descendants of which 168537006|Plain radiography (procedure) has 175 descendant concepts. 278110001|Radiographic imaging - action (qualifier value) appears more than 1600 times in either the stated or inferred relationships of existing content. It is also demonstrated that the procedure concepts impact content in the Clinical finding hierarchy. Current content contains a mixture of synonyms that are broader or narrower than the fully specified name of the concept and this is accompanied by inconsistent modelling. There are currently around 160 requests in SIRS that reference the words ‘X-ray,’ ‘radiography’ and ‘plain x-ray’ and clear guidance is required if the existing problems are not to be perpetuated.
End users will benefit from resolution of this content project with a solution that ensures that current content aligns with editorial policy and future content development will do the same. Application of a consistent approach will also ensure that duplicate concepts are identified and inactivated.
For those involved in translation, the implementation of a consistent approach to descriptions is likely to reduce anomalies in translated content and may assist with an algorithmic approach to translation.
By addressing this content and the existing new requests, overall quality and consistency of content will be improved. Content in this area is likely to be under increased scrutiny with the New Global Licensing Agreement for SNOMED CT Code Inclusion in the DICOM Standard.
Achieving a workable solution for this content project will also be of benefit to the IHTSDO content team, as the disposition of new requests will be consistent and more efficient. The value of the effort involved with the undertaking of this content project is considerable when considering its likely impact.
4.1.1 Risks of not addressing the problem
The project risk is calculated by utilizing the Project Risk Profile assessment tool as detailed on Page 11 of “A Guide to Stakeholder Engagement” https://confluence.ihtsdotools.org/pages/viewpage.action?spaceKey=CONSULTANTTERMINOLOGISTGROUP&title=Stakeholder++Engagement++Resources
Criteria | Analysis | Score |
Number of concepts affected | July 2016 release data:
| 2 |
Number of users affected | This content is widely used across National Release Centres and other users | 2 |
Changes to vendor software required | The solution is intended to reduce inconsistency in concept descriptions and modelling. There is no requirement for changes to software.
| 0 |
Change to concept model | None proposed. | 0 |
Change to content development software or processes | None required. | 0 |
Average score |
| 1 |
The risk level is assessed as a score of 1, which is medium risk.
If this problem is not addressed end users, vendors, NRC and the IHTSDO content team will remain unclear about editorial policy and this will lead to inconsistent inclusion of content and concept modelling.
In addition to the risks quantified above, not addressing the problem means that X-ray, plain X-ray and radiography concepts will be scattered inconsistently across hierarchies with inconsistency of descendent concepts. User queries for these concepts will consequently be more difficult to formulate, as there will be continue to be inconsistency in the way new content is modelled. In order to capture all instances of ‘radiography’, ‘X-ray’ and ‘plain X-ray’, extraction criteria will need to include different method action attributes.
Clear guidance will assist the content team to add and model new content in a consistent manner that prevents future recurrence of this problem. It is highly desirable to fully define new content in order to harness the benefits of using a classifier, optimise subsumption and eliminate equivalency.
4.1.2 Risks of addressing the problem
There is a large amount of content involved in this content project. Concepts across both the procedure and Clinical finding hierarchies will be impacted. However it is noted that changes to the Clinical finding hierarchy will be mostly the result of changes in inferred relationships from the resolution of existing problems with inheritance. Some review of descriptions may be required to align the clinical finding hierarchy content with the changes made to the procedure hierarchy.
Whilst improvement to the quality and consistency of the content is of benefit to all users, the implementation of proposed changes will result in amendments to released descriptions, modifications to existing hierarchies and inactivation of some released content. This may impact implementations of SNOMED CT.
However the potential negative impact of these factors may be mitigated by
Clinical review of the proposed solution to ensure it is robust reflects clinical practice and does not make assumptions that are not clinically valid.
Provision of detailed release notes when the changes are implemented
Ensuring that all inactivated concepts maintain a historical relationship to an active released concept that the end user can implement in place of the existing concept.
Updating editorial guidance to detail all changes that are made and how content of this nature will be added to SNOMED CT in the future.
5 Requirements: criteria for success and completion
5.1 Criteria for success/completion
All concepts that are in scope for this project will
Be clearly and consistently represented in SNOMED CT
Have descriptions that align to an agreed format
Have stated IS_A relationships, attributes and values that have been assigned in a consistent manner to ensure that classification results in logical inferred relationships.
5.2 Strategic and/or specific operational use cases
This content development project aligns with one of the core principles as outlined in the IHTSDO Strategic Direction 2015-2020 - Quality focused content development with adherence to strict editorial rules.
6 Solution Development
6.1 Initial Design
6.1.1 Modelling of Imaging Action
6.1.1.1 Option One
278110001|Radiographic imaging - action (qualifier value) groups all of the different radiographic procedures that are based on X-ray. The first option is to take the approach that 278110001|Radiographic imaging - action (qualifier value) be used sparingly because it will subsume all concepts that are modelled using a descendant imaging action such as 312251004|Computed tomography imaging - action (qualifier value). The proposal would therefore be to retain a small number of concepts as groupers with a text definition and clear editorial guidance for use and then re-model all granular descendant concepts (procedure with a finding site) to be a type of Plain X-ray.
6.1.1.2 Option Two
The second option is to consider 278110001|Radiographic imaging - action (qualifier value) the same as 312254007|Plain X-ray imaging - action (qualifier value). This would result in wide-scale inactivation of content. All existing content that uses the terms ‘radiograph,’ ‘X-ray’ and plain ‘X-ray’ would be remodelled with a method of 312254007|Plain X-ray imaging - action (qualifier value). This would have a large-scale impact across the imaging procedure hierarchy and require wider assessment and consultation. As demonstrated throughout this document, it is also the approach that is least aligned with clinical practice as there is a place for both ‘radiographic imaging’ procedures and ‘plain X-ray’ procedures as separate entities within SNOMED CT.
6.1.1.3 Modelling Recommendation
The initial recommendation is that ‘Option One’ be initiated, 278110001|Radiographic imaging - action (qualifier value) will group all of the different radiographic procedures that are based on X-ray. The following concepts should utilise the action 278110001|Radiographic imaging - action (qualifier value) and act as grouper concepts:
363680008|Radiographic imaging procedure (procedure)
108273007|Radiographic imaging procedure by site (procedure)
418542003|Radiologic guidance procedure (procedure)
27483000|Diagnostic radiography with contrast media (procedure)
The current descendants of these concepts are mostly localised with a body structure, which suggests that the original intent was ‘plain X-ray’ imaging of a particular structure and not a higher-level grouper.