Age-related changes in the parotid gland: a computed tomography-based radiomics study

Age-related degeneration of parotid glands impacts oral and systemic health, yet non-invasive assessment remains limited. This study characterizes parotid gland aging using computed tomography (CT)-based radiomics for the early detection of glandular dysfunction or diseases.

This retrospective study included 320 healthy individuals (aged 12-84 years), stratified into four age groups (adolescent: <25, young adult: 25-44, middle-aged: 45-59, elderly: >59 years) with balanced sex distribution. Axial medial-lateral diameter (AMLD) and mean Hounsfield unit (HU) attenuation were manually measured on axial CT slices. Three-dimensional (3D) radiomic features were extracted from automatically segmented glands via PyRadiomics platform. Dimensionality reduction was performed by probabilistic principal component analysis (PCA) and unsupervised K-means clustering was applied to shape-, first-order-, and texture-related features to identify age-associated patterns.

AMLD increased significantly with age from 32.1±3.5 mm in the adolescent group to 40.3±4.1 mm in the elderly group (P<0.05). Similarly, gland volume enlarged significantly, with males exhibiting larger volumes than females across all groups (P<0.05). In contrast, mean HU declined with age from -2.5±6.8 to -15.7±10.2 HU (P<0.05), indicating reduced tissue density and homogeneity. Radiomic uniformity also decreased significantly in adults compared to adolescents (P<0.05). Unsupervised clustering revealed a marked age-dependent shift: Cluster 1 (small, spherical glands) comprised 55.6% of adolescent glands but only 8.8% of elderly glands (P<0.05), whereas Clusters 3 and 4 (large, irregular glands) increased from 10.9% to 48.8% (P<0.05).

CT-based radiomics captured age-related morphological and structural changes in parotid glands. These findings support the application of CT as a non-invasive tool for monitoring parotid gland aging and may inform the early detection of age-associated glandular dysfunction.