Endocrine Abstracts

Introduction: The prevalence of thyroid nodules detected by ultrasound (US) is up to 50% in general population and approximately 5−10% of them is malignant. Diagnostic assessment includes laboratory tests thyroid US and thyroid scintigraphy, where suspicious nodules are characteristically cold when using^99m Tc-pertechnetate as a tracer. A useful tool for US-based risk stratification of thyroid nodules is Thyroid Imaging Reporting and Data System (TIRADS). Recently, a complementary role of elastography was shown. Our aim was to evaluate a diagnostic value of elastography using carotid artery pulsation in the assessment of cold solid thyroid nodules.

Methods: In 39 patients 31 females and 8 males (mean age 51.9±16.8 years), we evaluated solitary or dominant solid thyroid nodule that was cold on scintigraphy with^99m Tc-pertechnetate. In every patient, thyrotropin (TSH) was measured, thyroid and nodule volume were calculated using standard formula and TIRADS score was estimated on the basis of US characteristics. Elastography using carotid artery pulsation was performed and elasticity contrast index (ECI) of thyroid nodule and paranodular tissue was assessed. In every nodule, fine needle biopsy was performed and cytology was reported using Bethesda classification system. Patient and nodule characteristics were compared according to cytology result.

Results: Mean TSH level was 1.73±1.13 mIU/l. Mean thyroid volume was 29.6±18.9 ml and mean nodule volume was 13.4±14.9 ml. Males had significantly larger nodule volume than females (28.4±22.7 vs 9.6±9.3 ml, P = 0.05). Mean ECI of thyroid nodules was significantly higher compared with mean ECI of paranodular tissue (1.81±0.84 vs 1.09±0.34, P < 0.001). Suspicious Bethesda category (4 or 6) was confirmed in 20.5% (8/39) of patients. Compared with unsuspicious nodules, nodules with suspicious Bethesda category were confirmed in significantly younger patients (38.6±18.8 vs 55.4±14.6 years, P = 0.01), their proportion was significantly higher in males than in females (P = 0.02) and their TIRADS score was significantly higher (P < 0.001). Patients with suspicious or unsuspicious cytology did not differ with respect to mean ECI of thyroid nodule (2.2±1.3 and 1.7±0.6, P = 0.33), nodule volume (P = 0.71) or TSH concentration (P = 0.87).

Conclusion: Our results show a significantly higher ECI in cold solid thyroid nodules than in surrounding thyroid tissue. However, elastography with ECI evaluation does not seem to contribute significantly to the assessment of malignant potential of those nodules. Data based on larger number of nodules is needed to further evaluate the value of elastography.