Establishing absolute and vitreous-normalized reference apparent diffusion coefficient values of the lacrimal gland...

To establish normative apparent diffusion coefficient (ADC) values of the lacrimal gland in a large cohort of healthy subjects and to compare the results with previously reported data.

Retrospective cohort study.

Brain magnetic resonance (MR) images of 260 healthy individuals were retrospectively analyzed. ADC measurements were performed bilaterally using a standardized region of interest (ROI) technique. The values were compared according to age and sex. To ensure normalization and standardization, vitreous ADC measurements were performed using the same ROI used for lacrimal gland measurements. Lacrimal gland ADC values were divided by vitreous ADC values.

The lacrimal gland ADCmean value was 1.29 ± 0.14 ×10⁻³ mm²/s. No significant difference was observed in terms of ADC measurements between the right and left glands (p > 0.05). Sex had no statistically significant effect on ADC values (p > 0.05). The mean vitreous ADC value was 3.08 ± 0.20 ×10⁻³ mm²/s. The lacrimal gland/vitreous ADCmean ratio was 0.42 ± 0.05. Correlation analysis revealed weak positive correlations between age and lacrimal gland ADCmean (r = 0.185, p = 0.003) and ADCmax (r = 0.260, p < 0.001).

This study presents a large series on normative ADC values of the lacrimal gland in healthy individuals. The results provide reliable reference data that may assist in the differential diagnosis of inflammatory and neoplastic pathologies.