Comparison of planar bone scintigraphy and single photon emission computed tomography for diagnosis of active...

The aim of this study was to compare the reliability and correlations with age and gender of two nuclear medicine tests used for diagnosis of active condylar hyperplasia, namely, planar bone scintigraphy versus single photon emission computed tomography (SPECT).

This was a descriptive observational study carried out in 61 patients (38 women and 23 men) clinically diagnosed as having facial asymmetry and suspected unilateral condylar hyperplasia. The patients had both planar bone scintigraphy and SPECT diagnostic imaging as well as reference data of the percentage of (99)Tc(m) MDP (methylenediphosphonate) uptake in the 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 13-50 years (mean ± standard deviation = 21.16 ± 8.75). The two groups were compared by a nonparametric (Mann-Whitney U test. Uptake percentage and delta values had normal distribution and consequently were compared by a Student t test.

A total of 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 uptake with SPECT. The prevalence of condylar hyperactivity was higher in women than in men both for right condyle (ratio 4:3) and for left condyle (10:1) and the prevalence was significantly higher for the right condyle.

The study indicates that SPECT is more sensitive to identify condylar hyperactivity as compared to planar bone scintigraphy in patients with clinical presumptive diagnostic of condylar hyperplasia.