Ultrasound characteristics of Hashimoto’s thyroiditis in the subclinical stages of the disease

Objective

To investigate the prognostic value of indicators from b-mode ultrasound, color Doppler ultrasound, and strain elastography of the thyroid gland in the diagnosis of Hashimoto's thyroiditis (HT).

Methods

In 70 euthyroidal patients with HT, demographic characteristics, serum thyroid profile and ultrasound parameters, including thyroid gland size, vascularity and stiffness (elastography strain index) of the parenchyma, and flow indices of the superior and inferior thyroid artery were recorded. The control group consisted of 70 age and weight matched euthyroid individuals with negative anti-thyroid antibodies (anti-TPO and anti-Tg).

Results

A significant difference was observed between the two groups in total thyroid size (ml, median ± standard deviation, SD) 7.86 ± 2.9 in HT vs. 6.35 ± 2.7 ml in controls, p = 0.003) and parenchymal vascularity which was increased in patients with HT (p < 0.001). Tissue strain index was higher in the HT group but without reaching statistical significance In logistic regression, thyroid size (odds ratio 1.20, 95% confidence interval: 1.02–1.41, p = 0.022) demonstrated significant prognostic value for the presence of HT. No differences were found between the two groups, regarding the peak systolic velocity (PSV), end-diastolic volume (EDV), pulsatility index (PI) and resistive index (RI) values of the thyroid arteries. In the ROC analysis (AUC 0.653, p = 0.002), a thyroid size >7.3 ml exhibited sensitivity of 61.43% and specificity of 72.6% for the diagnosis of HT.

Conclusion

Patients with HT exhibit larger thyroid size and increased intrathyroidal vascularity on ultrasound prior to the manifestation of hypothyroidism compared to the healthy population. Flow indices of the superior thyroid artery do not have prognostic value in the diagnosis of HT.