Decreased thyroid uptake of Tc-99m pertechnetate in patients with advanced-stage Sjögren syndrome: evaluation using salivary gland scintigraphy.

Abstract

The authors assessed the uptake of Tc-99m pertechnetate in the thyroid using salivary gland scintigraphy in patients with Sjögren syndrome and in healthy controls. Salivary gland scintigraphy and a labial biopsy were performed in 73 patients with Sjögren syndrome. Based on the labial biopsy findings, 32 patients with a histopathologic grade of 1 or 2 were regarded as having early-stage Sjögren syndrome and 41 patients with a grade of 3 or 4 were regarded as having an advanced stage. After the administration of 370 MBq (10 mCi) Tc-99m pertechnetate, dynamic salivary gland scintigraphy was performed for 50 minutes. Lemon juice was used to stimulate the salivary glands, and the thyroid gland was included in the imaging area. Scintigraphy was also performed in an age- and sex-matched control group of 25 healthy persons. The thyroid uptake ratio was calculated for the scintigraphic images and compared among the three groups: healthy controls, patients with early-stage Sjögren syndrome, and those with advanced-stage Sjögren syndrome. When compared with the control group, the thyroid uptake ratio of the early-stage Sjögren syndrome group was not significantly different, whereas that of the advanced-stage group was significantly lower. Thyroid uptake of Tc-99m pertechnetate was less in patients with advanced-stage Sjögren syndrome than in patients with early-stage Sjögren syndrome or in healthy controls. Measuring the thyroid uptake of Tc-99m pertechnetate using salivary gland scintigraphy is an easy and useful method for assessing thyroid disorders in Sjögren syndrome and thus should be performed routinely.