Utility of colour Doppler sonography in patients with Graves' disease

Assessment of thyroid blood flow gives valuable information about underlying functional status. Colour Flow Doppler Sonography (CFDS) is a powerful tool which displays tissue blood flow and vascularity. Colour Flow Doppler Sonography of the thyroid gland in different subsets of patients with Graves' disease was studied to define its role in initial diagnosis and management.

Eighty consecutive patients with Graves' disease (both treated and untreated) presented to hospital between August 2007 and February 2008. All patients were evaluated with CFDS of the thyroid for size, vascularity and peak systolic velocity (PSV) of the Inferior Thyroid Artery (ITA). Pertechnate scan and thyroidal autoantibody levels were done in selected cases. The patients were divided into Untreated Graves' disease (n = 31), Graves' disease on treatment but hyperthyroid (n = 26) and euthyroid Graves' disease on therapy (n = 23). Mann-Whitney U-test was used for statistical analysis and a p-value of less than 0.05 was considered significant.

Thyroid blood flow, as assessed by PSV of ITA, was significantly higher in untreated Graves' disease than in Graves disease on treatment but hyperthyroid and euthyroid Graves respectively (61.5 +/- 19.5 versus 42.9 +/- 24.7 versus 32.2 +/- 12.9 cm/s, p < 0.05). Parenchymal vascularity of the thyroid gland was higher in hyperthyroid patients than in euthyroid patients irrespective of therapy. In both groups on therapy, the dose of carbimazole correlated with the vascularity of the gland (r = 0.492 versus 0.564, p < 0.05). Colour Flow Doppler Sonography parameters correlated significantly with pertechnate scan results giving comparable sensitivity and specificity.

Assessment of thyroid blood flow by CFDS is an effective marker in the initial diagnosis of Graves' disease. Vascularity of the gland can predict long term disease course while on medical therapy.