Utility Of Grayscale Contrast-enhanced Ultrasound In The Differential Diagnosis Of Thyroid Nodules

Objective To investigate the feasibility of contrast-enhanced ultrasound in the diagnosis of thyroid nodules and to evaluate the diagnostic value of conventional and contrast-enhanced ultrasound in the thyroid nodules.Materials and Methods From July 2007 to September 2009,85 pathologic proven thyroid nodules were studied using conventional ultrasound and contrast-enhanced ultrasound according our study protocol.52 nodules are benign including 39 hyperplasia nodules,9 follicular adenomas,2 Hashimoto disease,1 thyroid tuberculosis and 1 thyroid inflammation.33 nodules are malignant including 26 papillary carcionomas,6 follicular carcinomas and 1 medullar carcinoma. The size, shape, border, taller than wide, echo-texture, echogenicity, microcalcifications and blood flow of the nodules were investigated on conventional ultrasound. Comparison of above sonographic criteria were done between benign thyroid nodules and malignant nodules. Criteria that showed significant differences between benign nodules and malignant nodules were further evaluated for their differential diagnostic value between benign and malignant nodules. Contrast-enhanced ultrasound also was conducted on above nodules. Enhanced patterns were studied and compared between benign and malignant thyroid nodules.Results Statistically differences were revealed for lesion's shape, border, taller than wide, echogenicity and microcalcifications between benign and malignant nodules (P<0.05). Malignant nodules more likely demonstrated irregular in shape, ill-defined in border, taller than wide, marked hypoechogenicity and microcalcifications. Benign nodules showed more cystic texture and less blood flow than malignant nodules, but no significant differences were found. Taller than wide and microcalcification had higher specificity for the diagnosis of malignant nodules while marked hypoechogenicity has a high sensitivity for the diagnosis of malignant nodules. The criteria of ill-defined border has a high value in differentiating malignant from benign nodule with sensitivity, specificity and accuracy 72.7%,80.8%,77.6%。Contrast-enhanced ultrasound were conducted in 85 nodules, successful sonogram were achieved in 97.6% cases. Five enhanced pattern were showed in 83 nodules. For 37 hyperplasia nodules,16 (43.2%) demonstrated diffused hypo enhancement,11 (29.7%) diffused is-enhancement,3 (8.1%) hyper-echoic, 5(13.5%) ring-enhancement and 2(5.4%) hetero-enhancement. For 9 follicular adenomas,2 demonstrated diffused hypo enhancement,1 diffused is-enhancement, 66.7% (6/9)follicular adenomas showed diffused hyper-enhancement. Of 26 papillary carcinomas,8(30.8%)showed diffused hypoenhancement,1 is-enhancement,2 hyper-enhancement and 15(57.7%) hetero-enhancement.4 of 6 follicular carcinomas showed hetero-enhancement. The sensitivity, specificity and accuracy for the hetero-enhancement pattern in the diagnosis of malignant nodules were 57.5%,94.0% and 79.5% respectively. Ring-enhancement pattern has a high specificity for the diagnosis of hyperplasia nodules and diffused hyper-enhancement for the diagnosis of follicular adenomas.Conclusions Shape, border, echogenicity presence of microcalcification and taller than wide on conventional ultrasound are helpful criteria for the discrimination of malignant form benign nodules. Contrast enhanced US enhancement patterns were different in benign and malignant thyroid nodules. Hetero-enhancement pattern was helpful for detection malignant thyroid lesions.