Aim: This study investigated the enhancement patterns observed on contrast-enhanced ultrasound (CEUS) images for differentiating thyroid nodules.Material and methods: A retrospective review was conducted of CEUS cine loops of 252 nodules by two independent readers. Seven categories of enhancement patterns were identified: concentric hypoenhancement; heterogeneous hypoenhancement; hypoenhancement with sharp margin; homogeneous hyper/isoenhancement; hyper/isoenhancement with ring-like vascularity; island-like enhancement; and no perfusion. Associations between these patterns and the confirmed pathological/cytological outcomes (178 malignant, 74 benign) were analyzed and the sensitivity, specificity and positive predictive values (PPVs) determined. The agreement of the readers’ assessments was evaluated by Kappa value.Results: For malignant nodules, the predominant 3 patterns were: concentric hypoenhancement, heterogeneous hypoenhancement and homogeneous hyper/isoenhancement. For each of these, the diagnostic specificity was above 87% and the PPV more than 85%. Combining these patterns for malignancy the rates of sensitivity, specificity and PPV for reader 1 (reader 2) were 96.1% (98.9%), 71.6% (71.6%), and 89.1% (89.3%), respectively. For benign nodules, the predominant 4 patterns were: hypoenhancement with sharp margin; hyper/isoenhancement with ring-like vascularity; island-like enhancement; and no perfusion. The specificity for each was above 98% and the PPV more than 70%. Combining these patterns for benignity, the rates of sensitivity, specificity and PPV for reader 1 (reader 2) were 71.6% (71.6%), 96.1% (98.9%) and 88.3% (96.3%), respectively. The inter-reviewers agreement for classifying enhancement patterns was excellent (κ = 0.84, 95% CI: 0.79-0.89).Conclusions: Enhancement patterns of thyroid nodules on CEUS investigation, enable differentiation between malignant and benign lesions with good diagnostic sensitivity, specificity and PPV.

The present study aimed to establish a decision tree (DT) model by combining the parameters of conventional gray-scale ultrasonography (US), elastosonography (ES), color Doppler US (CDUS) and contrast-enhanced US (CEUS) for the differential diagnosis of thyroid nodules. A single-center, retrospective study of 321 thyroid nodules was conducted. For 222 nodules, parameters of conventional gray-scale US, CDUS, ES and CEUS were evaluated using univariate logistic regression. Factors for with P<0.10 were further assessed using multivariate logistic regression. Significant factors (P<0.05) were used to establish a DT. The diagnostic accuracy of this DT was then evaluated by its application to the other 99 nodules. After univariate logistic analysis, factors including gender, number of nodules and diffuse disease were excluded, due to P>0.10. The results of multivariate logistic analysis determined that the following factors were required for the DT: Extent of blood flow determined by CDUS (P= 0.002), area ratio determined by ES (P= 0.033), peak phase patterns determined by CEUS (P<0.001) and micro-calcification determined by conventional gray-scale US (P=0.015). When compared to the pathological or cytological results of 99 nodules, the resulting DT had a sensitivity of 98.6%, specificity of 80.1%, positive predictive value of 93.5% and negative predictive value of 95.5%. These results suggested that a DT combining conventional gray-scale US, ES, CDUS and CEUS may be helpful for differentiating between types of thyroid nodules.

Background: This study aims to compare the contrast-enhanced ultrasound (CEUS) characteristics of inflammatory thyroid nodules with those of papillary thyroid carcinomas using time-intensity curve (TIC) analysis.Methods: This was a retrospective cohort study. Among the thyroid nodules in 2161 patients who underwent CEUS from July 2014 to April 2018, 44 nodules in 44 patients ultimately diagnosed as inflammatory nodules and 44 nodules in 44 patients confirmed as papillary carcinomas (enrolled from July 2016 to April 2018) were included after propensity score matching analysis (1:1). The average diameters of lesions in the inflammatory and malignant groups (n=44 each) were 0.92±0.34 cm and 0.89±0.42 cm, respectively. CEUS patterns were evaluated and classified into four types, namely concentric hypo-enhancement, heterogeneous hypoenhancement, hypo-enhancement with a sharp margin, and homogeneous hyper/iso-enhancement. The measured TIC parameters included peak intensity (PI), rise time (RT), time to peak (TTP), maximum slope rate of the ascending curve (AS), and maximum slope rate of the descending curve (DS). The CEUS patterns and TIC parameters were compared between the inflammatory nodules and papillary carcinomas. Results:The heterogeneous hypo-enhancement CEUS pattern was predominantly present in the inflammatory nodules. The concentric hypo-enhancement pattern was identified as a valuable predictive pattern for papillary carcinomas. For the TIC, inflammatory nodules had a lower PI [55.42 (45.41, 76.91) vs. 84.43 (74.93, 90.92)] [median (interquartile range)] and a smaller AS [22.39 (13.37, 29.93) vs. 29.54 (19.37, 44.77)], compared with papillary carcinomas (P<0.05).Conclusions: CEUS patterns with TIC parameters could provide effective and quantitative information for characterizing microvascular perfusion of inflammatory thyroid nodules and papillary carcinomas.

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