Efficacy of apparent diffusion coefficient values for normal submandibular glands and acute submandibular sialadenitis

Objective: This study aimed to assess the apparent diffusion coefficient (ADC) values of normal salivary glands and acute submandibular sialadenitis (SS). Methods: This retrospective study included 22 patients who underwent magnetic resonance imaging (MRI) at the Nihon University School of Dentistry between February 2018 and May 2022. ADC values were compared between the acute SS and control group. Data with non-normality confirmed by Shapiro–Wilk test was analyzed using the Mann–Whitney U test, Spearman's correlation coefficient, and a receiver operating characteristic (ROC) curve. Statistical significance was set at p < 0.05. Results: The mean ADC values were 1.03 ± 0. 09 × 10⁻³ and 1.22 ± 0.17 × 10⁻³ mm²/s in the normal and acute SS groups, respectively (p < 0.001). ROC analysis revealed a cutoff ADC value of 1.1 for distinguishing acute SS from the normal. Conclusion: These findings suggest that ADC values are useful for the quantitative assessment of acute SS.