MR imaging of Sjögren syndrome : correlation with sialography and pathology

Magnetic resonance (MR) imaging of the parotid glands were performed in 13 cases of Sjögren syndrome to assess if there are any typical MR features. The MR findings were compared with sialography and pathology results. Signal intensity ratios of parotid (minus background noise) to skeletal muscle (minus background noise) were measured in these 13 cases as well as in 10 normal controls. Both T1- and T2-weighted images showed multiple hypointense mixed with hyperintense foci (salt-and-pepper appearance) throughout the glands in the six Sjögren cases of intermediate severity (46%), inhomogeneous glands in five cases with early or advanced disease, and homogeneous glands in the remaining two cases with the earliest stage of disease. Mean intensity ratios in T2-weighted pulse sequences in patients with salt-and-pepper appearance and inhomogeneous glands were significantly smaller than those in normal controls (p less than 0.05 and p less than 0.001, respectively). Pathologic studies tend to indicate that focal lymphocytic aggregates associated with increased interlobular fibrosis are probably responsible for the hypointense foci and the decrease in intensity ratios. We think that the salt-and-pepper appearance is suggestive of Sjögren syndrome and that the decreased intensity ratios combined with a typical clinical picture may lead to a highly probable diagnosis of this disorder.