Figure 3.

Schematic illustrating a discovertebral unit (the space between two horizontal lines drawn through the middle of adjacent vertebrae) with areas of bone marrow edema at different locations within the unit. This unit would therefore be considered as 'positive' for MRI inflammation even though none would be associated with the development of a syndesmophyte at the location indicated in the diagram. This methodological approach leads to a decrease in the strength of association between inflammation and new bone formation.