Role of color Doppler in differentiation of Graves' disease and thyroiditis in thyrotoxicosis.

AIM: To evaluate the role of thyroid blood flow assessment by color-flow Doppler ultrasonography in the differential diagnosis of thyrotoxicosis and compare it to technetium pertechnetate thyroid scanning.

METHODS: Twenty-six patients with thyrotoxicosis were included in the study. Clinical history was taken and physical examination and thyroid function tests were performed for all patients. Thyroid autoantibodies were measured. The thyroid glands of all patients were evaluated by gray scale ultrasonography for size, shape and echotexture. Color-flow Doppler ultrasonography of the thyroid tissue was performed and spectral flow analysis of both inferior thyroid arteries was assessed. Technetium99 pertechnetate scanning of the thyroid gland was done for all patients. According to thyroid scintigraphy, the patients were divided into two groups: 18 cases with Graves' disease and 8 cases with Hashimoto's thyroiditis. All patients had suppressed thyrotropin. The diagnosis of Graves' disease and Hashimoto's thyroiditis was supported by the clinical picture and follow up of patients.

RESULTS: Peak systolic velocities of the inferior thyroid arteries were significantly higher in patients with Graves' disease than in patients with thyroiditis (P = 0.004 in the right inferior thyroid artery and P = 0.001 in left inferior thyroid artery). Color-flow Doppler ultrasonography parameters demonstrated a sensitivity of 88.9% and a specificity of 87.5% in the differential diagnosis of thyrotoxicosis.

CONCLUSION: Color Doppler flow of the inferior thyroid artery can be used in the differential diagnosis of thyrotoxicosis, especially when there is a contraindication of thyroid scintigraphy by radioactive material in some patients.