Color Flow Doppler Sonography for the Etiologic Diagnosis of Thyrotoxicosis

Abstract

The objective of this prospective study was to compare the results of color flow Doppler sonography (CFDS) and radioiodine scintigraphy in patients with thyrotoxicosis. A total of 176 patients, 102 with clinical thyrotoxicosis and 74 with subclinical dysfunction, were included. Pregnant and breast-feeding women, patients using amiodarone or recently exposed to iodinated contrast, and patients treated with antithyroid drugs were excluded. Total T3, free T4, TSH, and anti-TSH receptor antibodies were measured before scintigraphy and CFDS. Excluding one patient whose etiology of thyrotoxicosis remained undefined, CFDS showed 100% specificity. In fact, in all 10 cases in which scintigraphy and CFDS provided discordant results, the diagnosis suggested by the latter was correct. In patients with clinical thyrotoxicosis, the sensitivity of CFDS was 96% for diffuse toxic goiter, 95% for the absence of hyperfunction, and 100% for toxic nodular disease. In patients with subclinical dysfunction, the sensitivity of CFDS was 72.7% for diffuse toxic goiter, 90% for toxic adenoma, and 86.6% for toxic multinodular disease. CFDS was inconclusive in patients with parenchymal blood flow with patchy uneven distribution or with macronodules in which nodule vascularity compared to the remaining parenchyma did not permit to establish the diagnosis with certainty. CFDS can be used instead of scintigraphy not only in situations in which the latter is contraindicated or of limited value to define the etiology of thyrotoxicosis.

Thyrotoxicosis associated with the use of amiodarone: the utility of ultrasound in patient management

“…Blood flow changes in thyroid parenchyma or nodules, and systolic blood flow velocities of thyroid arteries can be estimated. In a hyperfunctioning thyroid gland, hypervascularity is observed, and CFDS has been used in the diagnosis of Graves' disease, solitary adenoma and toxic nodular goitre . Peak systolic velocity of the superior thyroid artery has been shown to accurately differentiate Graves' disease from thyroiditis .…”

“…The benefit of this classification is that it allows separate evaluation of parenchymal diseases. Outside the context of amiodarone treatment, CFDS was inconclusive in patients with parenchymal blood flow with uneven distribution, or in the presence of macronodules …”

“…In a hyperfunctioning thyroid gland, hypervascularity is observed, and CFDS has been used in the diagnosis of Graves' disease, solitary adenoma and toxic nodular goitre. [28][29][30] Peak systolic velocity of the superior thyroid artery has been shown to accurately differentiate Graves' disease from thyroiditis. 31 However, it has not been studied in AIT; hence, its usefulness in this context is speculative.…”

“…Outside the context of amiodarone treatment, CFDS was inconclusive in patients with parenchymal blood flow with uneven distribution, or in the presence of macronodules. 30 On occasions, CFDS may show features that do not allow easy separation into different AIT groups, such as enlarged size with reduced vascularity or normal size with normal vascularity. A retrospective UK audit classified 20% of patients with AIT as having an indeterminate AIT type based on ultrasound appearances.…”

The value of ultrasonography for the indication of fine‐needle aspiration in autonomous thyroid nodules

“…In patients with hyperthyroidism, US/Doppler is used to investigate the etiology. When a nodule >1 cm is detected, scintigraphy with radioiodine is performed 17 . This imaging method is also used in patients with nodules >1 cm on US associated with low‐serum TSH.…”