CAN COLOUR FLOW DOPPLER REPLACE RADIO-ISOTOPE SCANNING IN THE DIFFERENTIAL DIAGNOSIS OF THYROTOXICOSIS?

Abstract

Objective: 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.
Patients and Methods: Twenty-six patients with thyrotoxicosis were included in the study. History, clinical examination and thyroid function tests including autoantibodies were done for all patients. Thyroid glands of all patients were evaluated by color-flow Doppler ultrasonography for size, vascularity, echotexture and blood flow in the inferior thyroid arteries. Technetium99 pertechnetate scanning of the thyroid was done for all patients.
Results: All patients had suppressed thyrotropin. According to Technecium pertechnetate scanning the 26 patients were divided into 18 cases with Graves' disease and 8 cases with thyroiditis. Thyroid blood flow, as measured by peak systolic velocity of the inferior thyroid arteries, was significantly higher in patients with Graves' disease than in patients with thyroiditis (P value=0.004 in the right inferior thyroid artery & P value=0.001 in left inferior thyroid artery). Diagnosis of Graves' disease and thyroiditis was supported by clinical picture and follow up of patients. 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 scanning of the thyroid by radioactive material cannot be done for any reason.