Dynamic Salivary Gland Scintigraphy: Establishing Normative Data through a Healthy Cohort.

Abstract

Purpose: The primary objective was to establish the normative data of dynamic salivary gland scintigraphy (dSGS). Secondary objectives included comparing salivary gland function across different glands, examining gender differences, and correlations with age.

Materials and methods: Twenty-nine consecutive healthy adults (19 females) with a mean age of 46.5 ± 11.9 years underwent dSGS. Scintigraphy images were analyzed visually and quantitatively, generating dynamic salivary scintigrams for each gland. Quantitative indices such as maximum percent uptake (MU%) and excretion fraction (EF%) were calculated. Comparisons between the parotid and submandibular glands, as well as between genders, were performed using the Mann-Whitney U-test or Independent Samples t-test. Spearman's rank correlation was used to analyze the relationship between age and the quantitative indices. Reference values for MU% and EF% were determined using the 5^th percentile and the mean - 1.645 × standard deviation, respectively.

Results: On visual analysis, parotid glands showed higher radiotracer uptake than submandibular glands. The dynamic scintigram displayed three distinct phases: accumulation, excretion, and re-accumulation. EF% was significantly higher in parotid than submandibular glands (P < 0.0001). No significant gender differences were found in MU% (P ≥ 0.422), but females had higher EF% in the parotid glands (P = 0.004) and a trend toward higher EF% in submandibular glands (P = 0.058). A weak positive correlation was noted between age and the MU% of the submandibular glands (Spearman's ρ = 0.391, P = 0.036). The reference cutoffs for MU% and EF% were determined to be ≥0.23% and ≥50% for parotid glands and ≥0.18% and ≥32% for submandibular glands, respectively.

Conclusion: This study established normative data of dSGS for evaluating salivary gland function. Further research with larger cohorts is recommended to explore age and gender variations and to validate these findings across diverse populations.