Influences of age and sex on the validity of bone scintigraphy for the diagnosis of temporomandibular joint osteoarthritis

Bone scintigraphy has been used for the diagnosis of early-stage temporomandibular joint (TMJ) osteoarthritis (OA) owing to its high sensitivity. However, the diagnostic value of bone scintigraphy may be compromised when applied to patients in an age range with high bone metabolism rates. The aim of this study was to investigate the validity of bone scintigraphy as an appropriate diagnostic modality for TMJ OA. A total of 406 subjects (145 male, 261 female; age range 14-87 years) were selected, and all subjects underwent both bone scintigraphy and computed tomography (CT). The diagnosis of TMJ OA was confirmed with CT. Images obtained with bone scintigraphy were analyzed by visual and quantitative methods using the TMJ-to-skull ratio. The TMJ-to-skull ratio was significantly higher during adolescence and elderly adulthood, but differences between the sexes were not significant. The diagnostic value of the TMJ-to-skull ratio was lower in elderly adulthood in both males and females. The diagnostic utility of visual assessment was also compromised during late adulthood in both males and females. Thus bone scintigraphy has little value in the detection of TMJ OA, because the results could be influenced by age-related bone metabolism rates.