The inclusion of Radiology terms within LOINC® began in January 2000 with the purpose of specifying a distinct study from a generic report type. The number of terms has increased significantly over the past 17 years and continues to grow each year. A Radiology LOINC term still has the six axes of the LOINC nomenclature, but they are defined with difference nuances to meet the needs unique to Radiology, as shown below.
LOINC Naming Convention of Six Axes for Radiology 
| LOINC Axis | How It Is Used | Example |
| Analyte/Component | What image/information will be evaluated | Views AP + Lateral, Multisection^WO & W contrast, etc. |
| Property | How image/information will be evaluated | Find |
| Time Aspect | How long it took to obtain image/information | PT |
| System | What body part/system will be evaluated | Spinal artery.left, Lower extremity.bilateral>Hip, Chest>Scapula, etc. |
| Scale | What the output of the order/observation will be | Document |
| Method | What modality was used to obtain the image/information | XR, CT, NM.SPECT, US, etc. |
The Radiology terms in LOINC got their start from many different standards as well as end user-specific databases. This approach has resulted in some odd looking terms, which may appear strange to someone not familiar with the many facets of diagnostic imaging. For example, CPT® groups images based on number of views (e.g., 4 or more views, fewer than 3 views, etc.). This nomenclature has been perpetuated in Radiology LOINC, sometimes making it difficult to map based on specificity.
Regenstrief Institute began a collaboration with the Radiological Society of North America (RSNA) in July 2015 to review and modify LOINC terms to more closely correlate with RSNA’s RadLex terminology. The first section of Radiology LOINC that has been evaluated and updated is Computerized Tomography (CT). As a result, the System axis has been clarified, not only for CT but for all modalities. The syntax is:
[<Body region imaged:][“>” <Imaging focus>]
Examples would be: Chest>Heart, Abdomen>Renal Vessels.bilateral, Head>Nasal bones
This change has been made to all Radiology LOINC from version 2.59 released in February 2017.
There is still a lot to be covered in Radiology LOINC, especially interventional procedures. We encourage everyone to support the Regenstrief Institute by submitting new terms and providing input on how Radiology terms are currently being used.
If you have questions or need help working with Radiology LOINC or RadLex, please contact us.