Submitters are advised to review existing Elements on radelement.org, perhaps in Elements Sets analogous to the Set being proposed, to get a sense of typical naming, definition and value set patterns.
Leave Element ID codes blank at the time of submission. They are assigned as part of the publication process.
Express the full semantics of the Element and provide a clear description of the specific intended use. A few words is typically inadequate; i.e., don’t just repeat the Element Name.
For Elements indicating the presence of a condition or disease, clearly state whether the value represents the current finding or is reiterating patient history.
For Elements that are measurements, define the method sufficiently to get consistent results. For example, clarify whether a diameter should be the greatest diameter in the imaging place, the AP dimension, short axis, long axis, etc. Most formats in which CDEs will be encoded (e.g. FHIR, DICOM SR), encode units for each measurement directly, usually using UCUM. The element definition may note default units to be assumed by coding systems that do not encode them directly.
Include references when the Element is based on established scientific literature, such as BI-RADS, TI-RADS, ASPECTS, SLICS, TLICS, NASCET, AoSpine, Fazekas Score and many others.
Think of the Element Name as a data item label within the Set.
Keep names as short as possible. Since elements all exist within the context of their specific parent Element Set, it is only necessary for the name to distinguish elements from the other elements in the same Set. The full semantics are in the Element Definition.
Avoid reiterating semantics already present in the Set Name. Avoid jargon and acronyms. The Name is not a prompt, and should not be in the form of a question.
Capitalize the first word of the name only ("Vascular territory", not "Vascular Territory").
It is acceptable (and desirable) for elements in different Sets to have the same name when they capture equivalent information. E.g. the Location element in the Pulmonary Nodule Set and the Location element in the Epidural Hematoma Set both capture the anatomical location of the pathology. Two such elements would still have different Element IDs, and definitions specific to the Set they are in.
If appropriate, consider the following terms for Element Names.
Qualitative Representation Terms:
- >: hyphen
- >: Category
- >: Characterization
- >: Classification
- >: Description
- >: Evaluation
- >: Location
- >: Score
- >: Severity
- >: Status
- >: Type
Quantitative Representation Terms
- Amount - Non-numeric categorical descriptor, e.g. few, many, etc.
- Average
- Count - Numeric value arrived at by counting.
- Degree
- Diameter
- Distance
- Length
- Quantity - Non-numeric categorical descriptor, e.g. few, many, etc.
- Rate
- Size
- Volume
- Width
Measure - Use more specific terms (rate, size, length, etc.) Number - Use “count” instead.
It is not necessary to include either “Presence of” or “Detection” in the element name to distinguish from other Elements that describe severity, type, etc. Values and definitions will provide context.
AVOID PREFER Brain swelling detection or Presence of brain swelling Brain swelling
Where there is a need for both detection and categorization fields within a set, combine these into a single Element and add value of “absent”. This is only appropriate for Elements that are single vs. multiple select to prevent documenting both “absent” and a category in error.
AVOID Separate Elements PREFER Combined Elements Element Name Values Element Name Values Herniation detection present absent Herniation absent uncal central Cingulate indeterminate Herniation type uncal central cingulate
Analogous to the case above of detection/categorization, when characterizing “appropriateness” (e.g., of the position of an enteric tube), one can define a single element with value of “appropriate” and multiple other values indicating inappropriate categories/abnormalities/incorrectness (e.g., “bronchus”, “gastreoesophageal junction”, etc.).
AVOID Element Name Specifies Usage PREFER Brief Element Name Element Name Values Definition Element Name Values Definition Anatomic focus of leg hip thigh knee leg ankle Anatomic focus of leg. Anatomic focus hip thigh knee leg ankle Anatomic focus of leg.
CDEs have four data types: Integer: a number used for observations that can be counted, such as a number of occurrences, or ordered Numeric: a floating point number used for measurements Value Set: a pick list from which one or more values can be selected
This may be a fixed response (present or absent), categorical with a fixed set of responses or a measurement with a defined upper or lower limits and potentially a default value. e.g.. hemorrhage: present/absent Hemorrhage type: epidural, subdural, subarachnoid, intraparenchymal, intraventricular. ASPECTS score ( 0 - 10) integer; default 10.
Indicate the number of values required for the containing Element Set to be valid. A value of 0 indicates the Element is optional. A value of 1 or more indicates the Element is required, i.e. that 0 values is invalid. Be judicious. Required means that if all other elements are present but this one is absent, then the Element Set must be rejected.
Indicate the number of values beyond which the containing Element Set is invalid. Most often, this is 1.
- Appropriate Units - The Unified Code for Units of Measure (UCUM) should be used as a reference for appropriate units. (Unit is currently a free text in the MARVAL authoring tool, however an update is pending that will limit users to UCUM units.)
Numeric = the decimal point can be set to the appropriate level of precision (eg, "step level: .1") and range of allowable values, and a unit of measure specified
Maximum limits for numeric entries will vary, however minimum allowable entry for numeric fields should be set as follows: Unit with minimum allowable entry
- cm = 0.1 cm
- mm = 1 mm
When describing volume the following are to be avoided. Volume Units -AVOID = cm3, mm3 -PREFER = mL, mcL
Example, in coronary artery imaging, several properties of a lesion (e.g., severity of stenosis, degree of calcification) can be assessed at different locations (left main artery, circumflex artery, obtuse marginal artery) in the coronary anatomy. There are two approaches:
- Define multiple data elements for each property at each possible location (e.g., separate element for stenosis at the circumflex, calcification at the circumflex, stenosis at the obtuse marginal, calcification at the obtuse marginal, etc.).
- Define a single data element for encoding each possible lesion where the location of the lesion is a possible choice (e.g., an element for lesion location [circumflex, obtuse marginal], and single elements for severity of stenosis and calcification). Which approach should be taken can be decided on a case by case basis, but in general, the first approach is favored.