Diagnostic Value of Contrast-Enhanced Ultrasound Evaluation of Malignant and Benign Solitary Thyroid Nodules

The aim of the study was to investigate the diagnostic value of contrast-enhanced ultrasound (CEUS) in differentiating benign and malignant thyroid nodules. Thirty-five patients with morphologically proved thyroid nodules (17 malignant; 18 benign), underwent CEUS examination. Five enhancement patterns were evaluated: vascularisation, homogeneity, presence of peripheral rim type enhancement, wash-out rate of the contrast medium, and enhancement using microvascular imaging application. Time-intensity curves (TIC) were analysed in post-processing and defined as three types: slow versus rapid and stable versus rapid biphasic wash-out. Diagnostic value of the listed CEUS parameters was calculated. The results showed medium strength correlation between morphology (benign versus malignant nodule) and type of TIC curve r_s = 0.38 (p = 0.021), as well as between mode of contrast enhancement r_s = 0.39 (p = 0.022) and wash-out pattern r_s =0.39 (p = 0.024). The overall pooled sensitivity of selected diagnostic parameters was 82%, specificity 57%, and accuracy 70%. Malignant nodules were characterised by iso- or hypovascular contrast enhancement and slow wash-out, while benign nodules showed hypervascular enhancement with rapid wash-out TIC curve and rim-like pattern. The CEUS patterns significantly differed between malignant and benign thyroid nodules with high diagnostic accuracy. Thus, CEUS has important clinical value as an additional tool to ultrasound and fine needle biopsy.