COMPARISON OF PLANAR BONE SCINTIGRAPHY AND SINGLE PHOTON EMISSION COMPUTED TOMOGRAPHY FOR DIAGNOSTIC OF ACTIVE CONDYLAR HYPERPLASIA IN PATIENTS WITH CLINICAL MANDIBULAR ASYMMETRY.

Objectives: To compare the reliability and correlations with age and gender of two nuclear medicine tests used for diagnostic of active condylar hyperplasia: Planar bone scintigraphy versus Single photon emission computed Tomography (SPECT).
Methods: Descriptive observational study carried out in 61 patients (38 women and 23 men) clinically diagnosed as having facial asymmetry, and suspected unilateral condylar hyperplasia. They had both Planar bone scintigraphy and SPECT diagnostic images as well as reference data of the percentage of ⁹⁹Tc^m MDP (methylen diphosphonate) uptake in condyle, clivus and fourth lumbar vertebra (L4), respectively for SPECT and planar scintigraphy calculations. Radioactive counts were measured per region of interest and the respective ratios were calculated. The age range of the patients was 13 – 57 year-old. (average ± standard deviation: 21,16 ± 8,75)
Results: 61 anterior planar images and 61 SPECT images were compared. Eight patients presented high uptake in planar bone scintigraphy images (13.11%), while 32 patients (52.46%) had high up take with SPECT. The prevalence of condylar hyperplasia was higher in women than in men both for the right condyle (ratio 4:3) and for the left condyle (10:1) and the prevalence was significantly higher for the left condyle.
Conclusions: The study indicates that SPECT is highly more sensitive to identify condylar hyperactivity as compared to planar bone scintigraphy in patients with clinical presumptive diagnostic of facial asymmetry.