Value of magnetic resonance sialography in evaluation of salivary gland function in patients with nasopharyngeal carcinoma treated with radiotherapy

Abstract

Objective To investigate the feasibility of magnetic resonance sialography (MRS) in the evaluation of salivary gland function in patients with nasopharyngeal carcinoma treated with intensity-modulated radiotherapy. Methods The MRS images of parotid and submandibular glands were collected in resting and stimulated states among 32 patients with nasopharyngeal carcinoma before and after radiotherapy. The visibility of the salivary ducts and radiation-induced xerostomia were evaluated, and the relationship between radiation-induced acute xerostomia grade and MRS score was analyzed. Comparison of the visibility and score between two groups was made by paired t test, and the correlation between acute xerostomia grade and MRS score was determined using the Spearman rank correlation method. Results Both the visibility of salivary duct and MRS score were significantly reduced after radiotherapy (P=0.000, P=0.000). There were significant differences in the variation of MRS scores of the parotid (DPS) and submandibular glands (DSS) from the resting state to the stimulated state between patients with severe and non-severe acute xerostomia (P=0.009; P=0.005). There were no significant differences in MRS scores of the parotid and submandibular glands in resting and stimulated states between patients with severe and non-severe acute xerostomia (P=0.881, P=0.305, P=0.327, P=0.229). The Spearman correlation analysis showed that the acute xerostomia grade was negatively correlated with DPS and DSS (R=-0.472, P=0.006; R=-0.482, P=0.005). Conclusions MRS score is correlated with xerostomia grade. MRS can be used to evaluate the salivary gland function in patients with nasopharyngeal carcinoma treated with radiotherapy. Key words: Xerostomia; Magnetic resonance sialography; Salivary gland; Nasopharyngeal neoplasms/radiotherapy