Salivary gland function evaluated by diffusion-weighted MR imaging with gustatory stimulation: preliminary results

Abstract

Purpose: To evaluate the usefulness of diffusion-weighted MR imaging using a transient gustatory stimulation method in patients with xerostomia.

Materials and methods: Ten consecutive patients complaining of xerostomia and 10 healthy volunteers were examined with a 1.5 Tesla (T) MR unit. All study subjects completed a questionnaire, and patients underwent salivary gland scintigraphy and Saxon test. T1-, T2-, and diffusion-weighted MR images were obtained before stimulation. One minute after gustatory stimulation with lemon juice, diffusion-weighted sequence was repeated 9 times. A radiologist evaluated signal intensities and apparent diffusion coefficients (ADCs) in parotid and submandibular glands. ADC increase rate (IR) and times to maximum ADC (Tmax) were assessed.

Results: IRs showed a moderate positive correlation with washout rates by scintigraphy for parotid (r = 0.554, P < 0.05) and submandibular (r = 0.617, P < 0.01) glands. Furthermore, Tmax values of parotid and submandibular glands were significantly higher in patients (420 ± 226 and 357 ± 232 s, respectively) than in volunteers (181 ± 68 and 200 ± 75 s, respectively) (P < 0.01).

Conclusion: Our preliminary results indicate that diffusion-weighted MR imaging using a transient gustatory stimulation method is potentially useful for evaluating patients with xerostomia.