Comparison of arfi findings and the fine needle aspiration biopsy results in the discrimination of benign and malignant thyroid nodules

Aim: The aim of this prospective study is to compare the ARFI, a non-invasive method, (Acoustic radiation force impulse, virtual touch quantification (VTQ)) elastography measurements, together with the B-mode ultrasound, with the results by taking the histopathological findings as reference standard in the discrimination of benign and malignant thyroid nodules and in the prediction of malignancy. Materials and Methods: 93 thyroid nodules from 82 patients were included in our study. All patients underwent conventional US examination and elastography examination using virtual touch quantification (VTQ) prior to histopathological sampling. Thyroid nodule localization, size, echogenicity of thyroid nodule, presence or absence of calcification, blood pattern, marginal arrangement and presence or absence of halo were evaluated by conventional examination. An average of 5 measurements were made from each nodule and SWVaverage values were calculated. Diagnostic performance was evaluated by receiver operating characteristic (ROC) analysis. The best cut-off values were determined by Youden index. Histopathological diagnosis was determined as the reference standard in the discrimination of benign and malignant thyroid nodules. Findings: Histopathologically, 64 thyroid nodules were reported as benign and 29 thyroid nodules as malignant. In the benign thyroid nodules, the average of SWVaverage values were 2.14 ± 0.59 m/s and the average of SWVaverage values were 3.63 ± 0.66 in the malignant thyroid nodules. SWVaverage values were significantly higher in malignant thyroid nodules compared to benign thyroid nodules statistically (p<0.001). Using the ROC curve, the best cut-off value for SWVaverage was found to be 2.77 m/s, and for differentiating benign and malignant thyroid nodules for SWVaverage, respectively the sensitivity, specificity, positive and negative predictive value and accuracy rates were calculated as 96.55%, 90.62%, 80.78%, 98.46%. Conclusion: It is thought that ARFI measurements, applying together with B-mode and color doppler ultrasound imaging, will contribute to the differential diagnosis in the discrimination of benign-malignant thyroid nodules, and that in terms of reducing the unnecessary biopsy and surgery applied to nodules, the shear wave technique of US-elastography will be able to take its place among the traditional methods in the following years with its quantitative values. Key words: Thyroid nodule, shear wave elastography, ultrasound, VTQ