Superb microvascular imaging compared with contrast-enhanced ultrasound to assess microvessels in thyroid nodules

Purpose Contrast-enhanced ultrasound (CEUS) and superb microvascular imaging (SMI) can detect microvessels in thyroid nodules. Here, SMI and CEUS were compared for differentiating thyroid nodules. Methods Seventy-six patients (102 nodules) underwent SMI and CEUS. The SMI blood flow (BF) grade and CEUS enhanced intensity (EI) were recorded for the periphery and center of each nodule, and evaluated relative to pathological findings. Results SMI of malignant nodules showed abundant BF in the periphery but lack of BF in the center, while CEUS showed hypoenhancement in the center and periphery. Large and small vessels had greater saliency on SMI-BF grade and CEUS-EI, respectively. Analysis of SMI-BF as diagnostic of thyroid carcinoma specifically at the nodule periphery indicated rates of 82.2%, 79.3%, and 81.3% for sensitivity, specificity, and accuracy, respectively. The corresponding rates for CEUS hypoenhancement were 80.8%, 86.2%, and 82.3%, respectively. Thus, SMI and CEUS rates were similar. Conclusion SMI-BF grade was more affected by vessels of larger inner diameter, while CEUS-EI was more affected by vessels of smaller inner diameter. SMI alone is sufficient for evaluation of blood flow in thyroid nodules, and the diagnostic value of SMI-BF of the periphery is comparable to CEUS hypoenhancement to differentiate thyroid cancer.