value of magnetic resonance sialography and magnetic resonance imaging versus conventional sialography of the parotid gland in the diagnosis and staging of Sjogren's syndrome

ABSTRACT

The conventional sialography [CS] and minor salivary gland biopsy have been considered the cornerstones of the diagnosis of Sjogren's syndrome [SS]. However, they are invasive and with risk of complications to the patient. Magnetic resonance imaging [MRI] has been widely replacing conventional invasive examinations. They provide insufficient data for diagnosing and staging SS, because while they address the detection and diagnosis of parenchymal salivary gland disease they do not assess duct abnormalities. The introduction of magnetic resonance sialography [MRS] protocol was the first step towards non-ionizing non-invasive technique enables a more accurate assessment of the duct system. Moreover, it is postulated that the combined use of MRI and MRS is useful for the assessment of damaged salivary glands in SS. This preliminary study aimed to assess the role and efficacy of MRS and MRI in imaging the parotid gland in SS patients' and to compare their results with that of CS in the diagnosis and staging of SS. The parotid gland was examined by MRS, MRI and CS in 15 SS patients. Scoring system for overall branching pattern, ductal system staging, sialectasis for both CS and MRS was used. MRI scoring system for glandular parenchymal pattern, size and contour and lymph node was used. This revealed non-significant difference between CS and MRS findings in the diagnosis and staging of SS. Furthermore, no statistically significant correlation was found between the clinical and SS stage in both CS and MRS. On the other hand, a statistically significant positive correlation was found between the clinical findings and the MRI parenchymal stages. Moreover, MRS showed higher sensitivity and diagnostic accuracy values than CS. Combining the MRS and MRI abnormalities, 100% sensitivity diagnostic accuracy values were achieved in the diagnosis and staging of SS. The inter-observer agreement was higher in MRS than in CS and was perfect in MRI. In this preliminary study, MRS showed a higher sensitivity and accuracy in diagnosing and staging SS and may safely and securely replace CS. MRI and MRS give information on different aspects of glandular and duct pathology; therefore, both should be performed when examining the parotid glands in SS patients