Establishment Of Diagnostic System For Benign And Malignant Thyroid Nodules With Gray-scale And Contrast-enhanced Ultrasound

Objective To evaluate the value of diagnostic ultrasound indicators, and to obtain rankings of valuable indicators in the diagnosis of thyroid nodules; to investigate the model of conventional ultrasound combined contrast-enhanced ultrasound (CEUS) in the diagnosis of thyroid nodules, and to analyze the optimal diagnostic points and clinical values; to discuss the rankings of ultrasound indicators in the diagnosis of thyroid nodules in different sizes, and to explore the value of CEUS in the diagnosis of thyroid nodules in different sizes.Methods Three hundred and seventy-five patients with 403 thyroid nodules including 135 benign nodules (67 follicular nodules,48 follicular adenoma,7 granulomatous thyroiditis,7 collagen fiber nodules and 6 fiber necrosis tubercles) and 268 malignant nodules (263 papillary carcinoma,2 follicular adenocarcinoma,2 medullary carcinoma,1 metastatic carcinoma) underwent preoperative ultrasound examinations including gray-scale ultrasound (GSUS), color Doppler ultrasound (CDUS) and contrast-enhanced ultrasound (CEUS). Twenty-four indicators of thyroid nodules including shape(BW1), orientation(BW2), boundary(BW3), halo(BW4), echogenicity(BW5), echo uniformity of the solid(BW6), interior structure(BW7), calcification(BW8), metastatic lymph nodes in the neck(BW9) and thyroid echogenicity (BW10) ten indicators on GSUS; vascular distribution(CD1), perforating branches(CD2), grades of vascularisation(CD3) and resistance index (CD4) four indicators on CDUS; relative arrival time of periphery and interior(CE1, CE2), peak peripheral and interior echogenicity(CE3, CE4), peripheral and interior washout echogenicity(CE5, CE6), homogeneity of enhancement(CE7), ring-enhancement(CE8), filling defect(CE9) and non-enhanced ring (CE10) ten indicators on CEUS were selected to evaluate all thyroid nodules. The differences between the benign and malignant thyroid nodules in all indicators were analyzed to screening indicators which were valuable in the differential diagnosis of thyroid nodules, and the rankings of the valuable indicators in terms of importance were obtained by principal component analysis. The model of valuable indicators in the diagnosis of thyroid nodules were investigated by logistic regression; and the optimal diagnostic points and clinical values of the model were explored by receiver operator curve (ROC) analysis. The included thyroid nodules were divided by size into group a (<10mm) and group b (≥10mm), and the rankings in group a and b of ultrasound indicators in the diagnosis of thyroid nodules were discussed.Results Nine indicators of gray-scale ultrasound (GSUS) and nine indicators of CEUS showed significant differences between the benign and malignant nodules (P<0.05), whereas four CDUS indicators had no value. The rankings of the valuable indicators were as follows:BW1,CE7, BW5, BW2, CE8, BW3, BW7, BW4, BW8, CE3, CE4, CE5, CE6, BW6, CE1,CE2, CE9, and BW9. The diagnostic model of the combination of GSUS and CEUS were y1= b1BW1+b4BW4+b7BW7+b8BW8+ b9BW9+C1CE1+c4CE4+c6CE6+c9CE9 (R2=0.857,P=0.00<0.05) and y2= 1.359BW1-1.386BW5-1.070BW6+1.545BW8+19.965BW9+2.004CE2+ 1.304CE4+1.181CE5 (R2=0.695, P=0.00<0.05). The area under the ROC curve for the model in the diagnosis of thyroid nodules were 0.964 and 0.934 (P=0.00<0.05), and the cut-off point for the diagnosis of thyroid nodules were y1=1.24, with a sensitivity of 92.9%, specificity of 88.9%; and y2=1.57, with a sensitivity of 79.8%, specificity of 95.6%. The CEUS indicators including CE3, CE5 and CE7 were important both in the<10mm thyroid nodules and in the≥10mm thyroid nodules; the CEUS indicators including CE9 and CE8 were more important in the≥10mm thyroid nodules than in the<10mm thyroid nodules; the CEUS indicators including CE4 and CE6 were more important in the<10mm thyroid nodules than in the≥10mm thyroid nodules.Conclusions Conjoint analysis of specific features of thyroid nodules on GSUS and CEUS could distinctly enhance the diagnostic value of thyroid nodules. Nine GSUS indicators and 9 CEUS indicators are ranging valuable in the differential diagnosis of thyroid benign and malignant lesions. The values of 9 CEUS indicators in the differential diagnosis of thyroid benign and malignant lesions vary with the size of nodules.