Usefulness of MR imaging of the parotid glands in patients with secondary Sjögren's syndrome associated with rheumatoid arthritis.

OBJECTIVE

To assess the correlation between MR imaging (MRI) of parotid glands with X-ray sialography, histopathology of the labial salivary glands, and salivary secretion, in patients with secondary Sjögren's syndrome (SS) associated with rheumatoid arthritis (RA).

METHODS

Non-contrast MRI of the parotid glands was performed in 13 secondary SS patients associated with RA who satisfied the revised Japanese diagnostic criteria for SS (1999), and the ACR/EULAR classification criteria for RA (2010). The MRI findings were classified according to the degree of high-intensity signal on T1-weighted images (T1WI) and short inversion time inversion recovery (STIR) images into five grades (0-4), using the modified Nagasaki University grading method. The results of MRI grading were compared with the Rubin and Holt staging of X-ray sialography (0-4), the Greenspan grading of labial salivary gland histopathology (0-4), and salivary secretion by the gum test (ml/10 min).

RESULTS

All 13 patients were females, with a mean age of 50.2 ± 11.3 years. According to the MRI grading, 3 patients were Grade 1, 5 were Grade 2, 5 were Grade 3, and none was Grade 0 or Grade 4. The mean stage by X-ray sialography was 1.7 ± 1.0, the mean grade by histopathology was 2.4 ± 1.2, and the mean volume of salivary secretion was 9.7 ± 3.9 ml. The MRI grading correlated significantly with the Rubin and Holt staging and Greenspan grading (P < 0.01 each, Spearman's rank correlation), and significantly and inversely with the results of the gum test (P < 0.05).

CONCLUSION

The results suggest that MRI of the parotid glands is a useful noninvasive tool for evaluating destruction and inflammation in the salivary glands.