What does it mean? The significance of radiographic changes in the neck and back

1. Diagnostic value of radiography

The first step in evaluating the clinical significance of neck/back radiographs is to decide whether or not you think that there are radiographic changes visible before you then proceed to judge their clinical significance.

Scenario 1:

You do not think that there are radiographic changes visible This could be because:
• There are none (in statistical terms this would be called a ‘true negative’). This does not mean that the horse does not have a neck/back problem. It simply means that there are no morphological changes present at this moment in time. The pain may well arise from the soft tissues or joints or there might be bone pain that has not resulted in morphological changes (yet).
• There are morphological changes but they are not picked up on radiograph due to technical limitations (e.g. superimpositions of structures that obscure a lesion) or the person who interprets the images does not spot a lesion or judges it to be within normal anatomical limits (in statistical terms these would be called ‘false negatives’).

Scenario 2:

You think there are radiographic changes visible This could be because:
• There are indeed morphological changes present (this would be called ‘true positive’). Ideal!
• There are no morphological changes, but you are fooled by artefacts into thinking there are or you interpret normal anatomical variations as pathological (this would be called ‘false positives’). […]