Diffusion-weighted MRI for differentiation between sialadenitis and pleomorphic adenoma.

OBJECTIVES

The aim of this study was to compare apparent diffusion coefficient (ADC) values from diffusion-weighted MRI (DWI) among normal salivary glands, cases with sialadenitis and cases with pleomorphic adenoma of major salivary glands.

METHODS

22 patients (totalling 44 major salivary glands) diagnosed with either unilateral sialadenitis (on either parotid or submandibular gland) or parotid gland pleomorphic adenoma were selected. Contralateral non-affected glands (normal) were also analyzed. DW images were achieved using a spin-echo pulse sequence with a 1.5-T MRI device. Mean ADC values were compared among the three groups analyzed (contralateral normal glands, sialadenitis and pleomorphic adenoma).

RESULTS

The mean ADC values were significantly higher in cases of parotid sialadenitis (p = 0.001), but not in cases of submandibular sialadenitis (p = 0.466), as compared with the contralateral non-affected glands. Cases of pleomorphic adenoma presented the highest ADC values of the study. In addition, one-way ANOVA test revealed a significant difference among the three groups of parotid glands analyzed.

CONCLUSIONS

Within the limitations of this study, the present results suggest that DWI allows for differentiation between parotid sialadenitis and pleomorphic adenoma.