Thyroid vascularization is an important ultrasonographic parameter in untreated Graves' disease patients

Abstract

Graves' disease is characterized by two sonographic features, hypoechogenicity and increased blood flow. The aim of this study was to review retrospectively ultrasound features and biochemical data of a cohort of untreated Graves' disease patients. We reviewed charts of 42 such patients, who were referred to our Endocrinology Unit from January 2013 to May 2018. One operator performed all the thyroid sonographic scans. Serum TSH, FT3, FT4 and TSH-receptor antibodies (TRAb) levels at the time of ultrasound examination were evaluated. Over a mean follow-up of 30.9 months, about one in three patients (38%) experienced at least one recurrence of hyperthyroidism (1.4 ± 0.6 recurrence per patient), either on or off antithyroid drugs. We found that thyroid vascularization correlated directly with thyroid volume and that larger thyroids tended to be more vascularized. We also found that greater vascularization was associated with marked hypoechogenicity, and greater FT4 and TRAb levels. Patients who experienced recurrence(s) had 1.7-fold higher levels of TRAb at onset. In conclusion, thyroid hypervascularization at onset of Graves' disease is an important sonographic feature.

Keywords: Doppler; Echopattern; FT3, triiodothyronine; FT4, thyroxine; Graves disease; Hyperthyroidism; Hypoechoic; TRAb, thyrotropin-receptor antibodies; TSH, thyrotropin; Ultrasonographic pattern; Ultrasonography; Vascularization.

Fig. 1

FT4 fold increase over the upper normal limit in the 42 Graves’ disease patients stratified based on the degree of thyroid vascularization. No patient had normal vascularization (score = 0).

Fig. 2

Correlation between age at onset and FT4 fold increase over the upper normal limit.