ABSTRACT
OBJECTIVE: To assess the condylar bone metabolic activity in patients with temporomandibular joint health by measuring 99m Tc-MDP uptake using a single-photon emission computed tomography (SPECT) to establish reference values of the uptake difference between condyles and the ratio with respect to the clivus. SETTING AND SAMPLE POPULATION: Eighty consecutive patients of both sexes who were admitted to a Nuclear Medicine Centre between 2017 and 2019 were included in the study. METHOD: This was an observational cross-sectional study in patients with SPECT indications to evaluate pathologies other than those of the temporomandibular joint. The values of the total and normalized counts in a fixed region of interest of five trans-axial slides were obtained to assess the percentage difference between the sides and the uptake ratio. The reference values are expressed as median and 5th and 95th percentiles. RESULTS: The sample included 53 women (66.25%) and 27 men (33.75%) aged 15-55 years. The percentage of uptake difference between condyles was 5.04% (0.46-14.78) for men and 5.17% (0.27-13.21) for women (difference not significant, P = .9). The uptake difference was below 10% in 85% of the subjects (n = 68). The ratio values for total counts in women (0.87, 0.46-1.33) were significantly different (P = .0030) from those in men (1.08, 0.61-2.09). No significant correlation with age was found. CONCLUSIONS: These new reference ranges are applicable to the diagnosis of unilateral and bilateral condylar hyperplasia.
