This study aims to verify the clinical value of thyroid ultrasound with microvascular flow imaging in thyrotoxic patients for differential diagnosis between hyperthyroidism and thyroiditis. We intend to use the RS85 Ultrasound device manufactured by Samsung Medison. Graves' disease and painless thyroiditis/subacute thyroiditis are the main cause of thyrotoxicosis.

Precise discrimination between Graves' disease and painless thyroiditis/subacute thyroiditis is clinically very important in determining treatment methods, such as the prescription of antithyroid drugs. Primary endpoint was to verify the value of vascularity index, defined by Blood pixel in range of image / Total pixel in range of image .Seondary endpoint was to verify the superiority value of Microvascular flow imaging to discriminate thyrotoxicosis patients compared with Color doppler/ Power doppler ultrasound imaging and conventional ultrasound imaging.

Thyrotoxicosis refers to the appearance of various clinical symptoms or signs due to and excessive increase of thyroid hormone in the body. Graves' disease, which causes thyrotoxicosis, is one of the most common autoimmune diseases and is known to account for 0.5% of the population. Precise discrimination between Graves' disease and painless thyroiditis/subacute thyroiditis is clinically very important in determining treatment methods.

The Microvascular flow imaging technology is expected to show higher sensitivity and accuracy than conventional color Doppler images in differentiating patients between Graves' disease and painless thyroiditis/subacute thyroiditis. We enrolled thyrotoxicosis patients in their initial presentation and used RS85 Ultrasound device manufactured by Samsung Medison to discriminate Graves' disease and painless thyroiditis/subacute thyroiditis. Power / Color doppler ultrasound imaging and conventional ultrasound imaging were used. Tranverse and longitudinal plane of the dominant lobe were selected for imaging. Doppler Adler's method was used to asscess vascularization. To assess the vascularity index, which is defined by Blood pixel in range of image / Total pixel in range of image, we selected the total tranverse plane of the thyroid as range of image.

Inclusion Criteria:

• Initial presentation with thyrotoxicosis

Exclusion Criteria:

• Past history of thyroidectomy
• Factitious thyrotoxicosis
• Unable for ultrasound

Patient with thyrotoxicosis initially presented at hospital.