What does it mean? The clinical significance of scintigraphy findings

Increased radiopharmaceutical uptake (IRU) does not equate with pain. There are common sites of IRU which are rarely associated with pain and lameness including the proximal dorsal diaphyseal region of the proximal phalanges [1], exostoses involving the second and fourth metacarpal/metatarsal bones and the third and fourth metatarsal bones [2]. There is usually greater RU in the articular processes of the caudal cervical vertebrae compared with the mid-neck region. The pattern of RU in the subchondral bone (SCB) of joints varies depending on the symmetry of loading of that joint and in some joints the work discipline and intensity [3–6]. There is invariably greater RU in the distal lateral aspect of the third tarsal bone and proximal aspect of the third metatarsal bone compared with medially. Elite showjumpers have greater RU in the dorsal aspect of the central and third tarsal bones compared with nonelite horses and horses from other disciplines [4]. Thus any focal area of apparent IRU must be interpreted with care. The RU throughout the entire limb should be compared with the contralateral limb; generalised differences often occur in lame vs. nonlame limbs. In some locations such as the tuber ischia, IRU may persist long-term, well after the original injury has become asymptomatic. It is crucial to be aware of normal RU patterns and their variability and to recognise that focal intense IRU may be an incidental finding. Scintigraphy can throw up many spurious results which are clinically irrelevant. […]