RESUMO
PURPOSE: To assess the lacrimal glands in patients with thyroid eye disease with diffusion-weighted magnetic resonance (MR) imaging. MATERIAL AND METHODS: This study was carried out on 44 consecutive patients (17 males, 27 females, with mean age 36 years) with thyroid eye disease and 20 age- and sex-matched volunteers. They underwent diffusion-weighted MR imaging of the orbit. The apparent diffusion coefficient (ADC) values of the lacrimal glands were calculated and correlated with the clinical activity score (CAS). RESULTS: The mean ADC of lacrimal glands in thyroid eye disease (1.73 × 10-3 mm2/s) was significantly higher (p = 0.001) than that of volunteers (1.52 × 10-3 mm2/s). The cutoff ADC value of lacrimal gland used for differentiation of thyroid eye disease from volunteers was 1.62 × 10-3 mm2/s with an area under the curve value of 0.95 and an accuracy of 96%. There was significant difference (p = 0.03) in the ADC of the lacrimal glands in patients with active (n = 24) and inactive (n = 20) disease. The cutoff ADC value of the lacrimal gland used to suspect active disease was 1.76 × 10-3 mm2/s with an area under the curve value of 0.80 and an accuracy of 82%. There was positive correlation between the ADC value of the lacrimal glands and CAS (r = 0.73, p = 0.001). CONCLUSIONS: The ADC of the lacrimal glands is a non-invasive imaging parameter that can be used for diagnosis of thyroid eye disease and to predict the active form of the disease.
RESUMO
BACKGROUND: To assess the role of diffusion-weighted MR imaging in differentiation between Graves' disease and painless thyroiditis. MATERIAL/METHODS: A prospective study was conducted among 37 consecutive patients with untreated thyrotoxicosis (25 female and 12 male; mean age of 44 years) and 15 ageand sex-matched controls. Diffusion-weighted MR imaging of the thyroid gland was performed in patients and controls. The apparent diffusion coefficient (ADC) value of the thyroid gland was calculated and correlated with Tc-99m uptake and thyroid function tests of the patients. RESULTS: There was a significant difference in the ADC value of the thyroid gland between patients and the control group (P=0.001). The mean ADC value of the thyroid gland in Graves' disease was 2.03±0.28×10-3 mm2/sec, and in patients with painless thyroiditis 1.46±0.22×10-3 mm2/sec, respectively. There was a significant difference in the ADC values between Graves' disease and painless thyroiditis (P=0.001). When the ADC value of 1.45×10-3 mm2/sec was used as a threshold value for differentiating Graves' disease from painless thyroiditis, the best result was obtained with area under the curve of 0.934, accuracy of 83.8%, sensitivity of 95.8%, and specificity of 61.5%. The mean ADC value of the thyroid gland in patients positively correlated with serum TRAb and Tc-99m uptake (r=0.57, P=0.001 and r=0.74, P=0.001, respectively). CONCLUSIONS: We concluded that ADC values of the thyroid gland can be used to differentiate Graves' disease from painless thyroiditis in patients with untreated thyrotoxicosis.
