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Objective We analysed the correlation between magnetic resonance images of the parotid and submandibular glands and the salivary flow rate in patients with Sjogren's syndrome. Methods We retrospectively reviewed magnetic resonance images (heterogeneous signal-intensity distribution and gland volume on T1- and fat-suppressed T2-weighted images, and multiple high-signal-intensity spots on magnetic resonance sialograms in the parotid and submandibular glands) obtained from 66 patients who were diagnosed with Sjogren's syndrome. We evaluated the relationship between these imaging features and their salivary flow rates in stimulated and unstimulated conditions. Results We found that as the disease progressed, both the heterogeneous signal-intensity distribution and the volumes of the parotid and the submandibular glands were significantly related to the stimulated and the unstimulated salivary flow rate. These imaging features were more highly correlated in assessments of the submandibular gland than in those of the parotid gland for both stimulated and unstimulated salivary flow rates. Conclusions Magnetic resonance image features of heterogeneity and smaller volume in the submandibular gland are reliable for predicting hyposalivation related to the progression of Sjogren's syndrome.

Objective We experimentally compared the effects of compressive and tractional mechanical stress on the temporomandibular joint (TMJ) of rabbits to assess the etiology of progressive condylar resorption. Materials and methods We performed a cortical osteotomy using custom-made devices that were lengthened by 0.25 mm every 12 h for 1 week after surgery. During this time, the rabbit TMJ was under compressive or tractional mechanical stress. The samples in each group were examined using micro-computed tomography and histological staining. Results Scores for the area of bone resorption were higher in the compressive group than in the tractional group. Moreover, scores for the depth of bone resorption were higher in the compressive group than those in the tractional group. We observed a significantly higher prevalence of resorption in the subcondylar bone in the compressive group than in the tractional group. There were substantially more cells that were positive for tartrate-resistant acid phosphatase in the compressive group than in the control and tractional groups. Conclusions The outcomes here suggest that excessive mechanical stress, particularly compressive mechanical stress, may significantly affect morphological bone change findings in the TMJ.

Objective We analyzed the diagnostic performance of the MR imaging findings of the parotid, submandibular, and sublingual glands to discriminate between patients with and without Sjogren's syndrome. Methods We retrospectively analyzed the correlation between the MR imaging and histopathological findings obtained from 69 patients with clinically suspected Sjogren's syndrome. We evaluated the heterogeneous signal intensity distribution on T1- and T2-weighted images, the multiple high-signal-intensity spots on MR sialograms, and the volume of the parotid, submandibular, and sublingual salivary glands. Results The multiple high-signal-intensity spots in the parotid gland showed the highest sensitivity and diagnostic accuracy (82% and 83%, respectively). In addition, the multiple high-signal-intensity spots and the heterogeneous signal intensity distribution in the submandibular gland showed high specificity (100% and 88%, respectively). The volume of the submandibular gland, but not that of the parotid or sublingual gland, was smaller in patients with Sjogren's syndrome. Conclusions The presence of multiple high-signal-intensity spots on an MR sialogram in the parotid gland should be considered the best diagnostic indicator for Sjogren's syndrome. The presence of spots, heterogeneity, and the change to smaller volumes in the submandibular gland were also helpful because of their high specificity, particularly in advanced cases. This article is protected by copyright. All rights reserved.