In ACs manifesting as pGGNs on CT images, nodule size is positively related to size and number of histologically invasive foci. However, invasive foci can be found in pGGNs smaller than 10 mm. Measuring volume and density of pGGNs provides no advantage over two-dimensional size measurements, which appear sufficient for risk estimation in clinical practice.

• Contrast-enhanced ultrasound (CEUS) helps differentiate between benign and malignant thyroid nodules. • Quantitative CEUS analysis yields sensitivity of 76.9% and specificity of 84.8%. • CEUS may be a potentially useful adjunct in assessing thyroid nodules.