The Value Of Color Doppler Flow Imaging In Differentiation For Benign From Malignant Thyroid Solid Nodules

Objective To evaluate the value of Color Doppler Flow Imaging(CDFI) in differentiating benign from malignant thyroid solid nodules(TSN) by studying the characteristic of CDFI and artery-to-vein ratio of the TSN.Materials and Methods112patients(a total of131nodules) with thyroid solid nodules or mainly solid nodules who were to undergo surgery were examined by two-dimensional gray-scale ultrasound (2DU) and CDFI.2DU evaluated the shape, margin, internal echogenicity, halo sign, microcalcification and posterior echo attenuation of the nodules. The flow pattern and blood supply were evaluated with CDFI. The differences between benign nodules and malignancy were assessed according to size(≤lcm in size and>1cm in size). Pulsed wave doppler (PW) observed artery flow spectrum form in nodules and compared peak systolic velocity (PSV), end diastolic velocity (EDV) and resistive index (RI) between benign and malignant nodules. Measured the different parts of the flow spectrum in the nodules on the most abundant blood flow cross-section and distinguished whether it was arterial or venous flow then calculate artery-to-vein ratio. Analyzed differences of the ratio between benign and malignant nodules and evaluated the differential diagnostic value of artery-to-vein ratio in nodules.Results (1)2DU evaluated the margin, halo sign, Anteroposterior/Transv-erse(A/T), internal echogenicity, microcalcification and posterior echo attenuation of the benign and malignant thyroid nodules and showed statistical significance (P<0.05).(2) CDFI with blood flow patterns showed statistical significance(P<0.05) between benign and malignant thyroid nodules. Mixed and peripheral flow patterns were observed in the majority of benign nodules, while internal oriented flow pattern in the malignant thyroid nodules.There was no significant difference(P>0.05) in blood supply of all nodules. By using Spearman rank correlation, blood supply within nodules was positively related with the size of nodules (r=0.423, P<0.05).(3) Malignant thyroid nodules had higher RI than benign ones,but there was no statistical significance in PSV and EDV.(4) The blood flow in artery-to-vein ratio of malignant nodules had the artery type of the majority while benign nodules with vein type or mixed type were in the majority, and these two groups were markedly different(P<0.05). The diagnostic sensitivity, specificity, positive predictive value, negative predictive value, agreement rate of malignant thyroid nodules respectively were75.0%.91.2%.78.9%.89.2%.86.3%, as a diagnostic criterion, more accurate than flow distribution model of type Ⅲ.Conclusion Internal oriented flow pattern was available for differential diagnosis of benign and malignant TSN. The artery type of the blood flow in nodules provided a supplemental valuable information for predicting thyroid malignancy.