Diagnostic value of contrast-enhanced ultrasound in solid thyroid nodules with and without enhancement

Abstract

We aimed to investigate different enhancement patterns of solid thyroid nodules on contrast-enhanced ultrasound (CEUS) and then to evaluate the corresponding diagnostic performance in the differentiation of benign and malignant nodules with and without enhancement. 229 solid thyroid nodules in 196 patients who had undergone both conventional ultrasound and CEUS examinations were classified into enhancement and non-enhancement groups. Besides, different enhancement patterns in the enhancement group were characterised with five indicators including arrival time, mode of entrance, echo intensity, homogeneity, and washout time. Then aforementioned indicators were compared between benign and malignant nodules of different sizes (<10 mm and >10 mm), and diagnostic performance of significant enhancement indicators was calculated. As for the enhancement group, there were statistically significant differences of <10 mm subgroup among three CEUS indicators including arrival time, mode of entrance, and washout time between malignant and benign thyroid nodules (p < 0.05), while all CEUS indicators showed statistically significant differences in the total group and ≥10 mm subgroup (p < 0.05). All the five CEUS indicators displayed better diagnostic performance with specificity (92.86, 92.14, 95.71, 90.71, and 90.71 %, respectively) and diagnostic accuracy (80.79, 79.48, 74.67, 75.11, and 81.66 %, respectively), while the sensitivity and negative predictive value of non-enhancement were 95.51 and 95.83 %, respectively, with an accuracy of 77.29 %. CEUS is a very promising diagnostic technique that could improve the diagnostic accuracy of identifying benign thyroid lesions to spare a large number of patients an unnecessary invasive procedure.

The EFSUMB Guidelines and Recommendations for the Clinical Practice of Contrast-Enhanced Ultrasound (CEUS) in Non-Hepatic Applications: Update 2017 (Long Version)

“…The following parameters are evaluated: area of ROI, wash-in slope, time to peak, peak intensity, area under the curve, mean transit time and washout [369,373]. Time-intensity curve patterns of washout may appear as poly-phasic or mono-phasic related to the heterogeneity of the nodule and histology, with a sensitivity, specificity and accuracy of 76.9 %, 84.8 % and 82.6 %, respectively [373,375,376].…”

“…Nodule size affects CEUS examination and interpretation. A nodule < 10 mm shows absent vascularization (incomplete neovascularization), while larger nodules > 10 mm appear hypervascular [369,371,375].…”

“…No single indicator is sufficiently sensitive or specific. Therefore, the results should be interpreted in conjunction with the clinical data, conventional US and other imaging examination findings to improve diagnostic accuracy in the assessment of thyroid nodules [371,372,375].…”

Thyroid Ultrasound: State of the Art. Part 2 – Focal Thyroid Lesions

“…Some authors reported that hypoenhancement is the most accurate US feature of malignancy on CEUS with high sensitivity, specificity and accuracy 82%, 85%, and 84%, respectively [23][24][25][26][27]. Three recent meta-analyses reported high-pooled accuracy of CEUS in diagnosing benign from malignant nodules with sensitivity, specificity, and positive and negative LR ranging 0.85-0.88, 0.87-0.90, 5.8-8.6 and 0.15-19 respectively [27][28][29].…”

Acoustic Characterization and Enhanced Ultrasound Imaging of Long‐Circulating Lipid‐Coated Microbubbles

“…By making use of US contrast agent microbubbles, contrast‐enhanced US represents an important breakthrough in the ability of US imaging by enhancing the returning US signal . Microbubble contrast agents are currently used for several clinical applications, such as identification and characterization of tumors, evaluation of myocardial perfusion, and assessment of vessel patency, and have been proven to be effective agents for drug delivery …”