| Background and objective In recent years, as people emphasis on their own health and the improvement of high frequency ultrasonic diagnosis technology, more and more thyroid nodule was detected. In general population, the detection rate was 3%- 7% by palpation, while the detection rate was 20%-67% by high resolution ultrasound, in which thyroid cancer accounts for 5%-10%, most of them were found in women and the elderly. Ultrasound has become the preferred imaging examination method of thyroid disease for its simplicity of operator, no radioactive damage, repeatable inspection, low cost and so on. However, the ultrasound diagnose is based on the morphological characteristics to identify benign or malignant nodules, but due to the examiner’s subjective factors, as well as lacking in standardization and normalization of terminology assessment of thyroid nodules, resulting in that the assessment of thyroid nodules in the same period, the same case, the same physician may draw a different conclusions, or the same image in the same case, different doctors may have different diagnosis, this will cause problems in patients and thyroid surgeon, and influence the communication between ultrasound and clinical departments, affecting diagnostic quality. As the preferred imaging examination method of thyroid disease, unified and standard of ultrasound diagnosis in thyroid disease, not only can it provide valuable reference information for clinicians, but also it can avoid unnecessary surgery, bringing huge economic benefits to society. In 2009, foreign scholars Horvath first proposed the thyroid nodules imaging reporting and data system(TI-RADS) on the basis of United States of radiology breast imaging reporting and data system(BI-RADS).This level of assessment intends to help standardize the ultrasound diagnosis of thyroid nodules, but its’ application in our country is ambiguous, and the authenticity of the malignant risk in each level has not been confirmed. In recent years, there are different domestic and foreign researchers attempt to establish the thyroid nodule TI-RADS assessment level, although these evaluation methods is very practical, but it was not widely spread in our country, because of its’ relatively complicated application process, not suitable for China’s national conditions of large population and significant amount of ultrasound doctors’ workload. Although the ultrasonic features of thyroid nodules is complex, and there are some overlap between benign and malignant nodules features, the ultrasonographic performance of different thyroid nodules still has certain rules to follow. In order to make the ultrasound assessment of thyroid nodule more simple and quickly, in this study, we divided thyroid nodules into different types based on the regularity of ultrasonographic features and how much the suspicious malignancy features in different thyroid nodules, and assessed the malignant risk of each type, to achieve the purpose of rapid and accurate diagnosis of thyroid nodules.Materials and methods 1 Research object We randomly collected patients with thyroid nodules from January 2014 to September 2015 at the Affiliated Cancer Hospital of Zhengzhou University, 461 cases in total, 103 cases of male, 358 cases of female, ages rangs from 2 to 80 years old, the average age at(49.2 ± 12.1) years, single nodules 107 cases, multiple nodules 354 cases, with a total of 785 nodules. Thyroid ultrasound examination of all patients were proceeded within two weeks before operation in our department. Clinical information is complete. The pathologic types of all nodules were confirmed by surgery pathology. 2 Apparatus and method The philips IU- Elite, IU- 22 color doppler ultrasonic diagnostic apparatus was used, then select the high frequency probe with the frequency at 5-12 MHZ. Patient lied supine without the pillow, and multiple slice scanning was used. Two-dimensional color-Doppler ultrasonic performance were carefully observed in each patient, such as nodule number, size, shape, aspect ratio, border, margin, internal echo level, internal echo structure, internal echo uniformity, echo of surrounding tissue, halo, calcification,rear echo and so on. Then color doppler flow imaging(CDFI)was used to observe the distribution of blood flow in the interior and peripheral of thyroid nodules. Afterwards switching to the ultrasound elastography(UE) condition to assess the softness of thyroid nodules, using the surrounding normal thyroid tissue as a reference. 3 Statistical analysis(1) SPSS17.0 software packages was used. The postoperative pathological was used as the gold standard, and chi-square test was employed to analysis the characters in thyroid nodule. It is statistically significance different when P < 0.05. Select malignant thyroid nodule indicator in ultrasound diagnosis preliminaryly.(2)Multiariable logistic regression analysis was used in the selected indicator, then ultrasound diagnostic indicator highly correlated with malignant nodules was selected.(3) The main indicators of ultrasound diagnosis of malignant thyroid nodules, such as sensitivity, specificity, accuracy, positive predictive value, negative predictive value, was calculated.(4) Thyroid nodules were classified, according to different sonographic features regularity and how many suspected malignant ultrasound findings in thyroid nodules, and then assess the risk degree of malignant nodules in various types.Results 1 The main ultrasound diagnosis index of the malignant thyroid nodules According to logistic regression analysis, nodules with irregular shape, A/T≥1, edges unsmooth, very low internal echo levels, with micro-calcifications or simultaneously with coarse calcifications and micro-calcification, rear attenuation, capsular invasion, flexible rates above 4, the above eight variables entered into the model. They were main ultrasound diagnostic criteria for diagnosis of malignant thyroid nodule. 2 The ultrasound classification of thyroid nodules Thyroid nodules can be divided into the following six types: typeⅠ- cystic nodules; Type Ⅱ- no suspicious signs of malignant mixed nodules, mainly including cystic(cystic component ≥50%) and solid-based(cystic component <50%) of the nodules;Type Ⅲ-follicular tumor-like nodules; Type Ⅳ- tiny cancerous nodules; Type Ⅴ- Fuzzy malignant nodules border with no suspicious signs; Type Ⅵ- highly suspected malignant nodules. 3 The risk degree of malignant nodules in various types Type Ⅰ- malignant risk is 0%; Type Ⅱ- malignancy risk is 4.2%; Type Ⅲ-malignancy risk is 19.8%; Type Ⅳ- malignancy risk is 79%; Type ⅴ-malignancy risk is 8.53%; Type Ⅵ- malignancy risk is 100%.Conclusions 1.According to the sonographic features of benign and malignant thyroid nodules, the main diagnostic indexes for the diagnosis of malignant thyroid nodules were screened out. 2.According to how many suspected malignant ultrasound findings in thyroid nodules and different sonographic features regularity, the thyroid nodules can be classified into six types, the risk degree of each type is different. 3. The ultrasound classification of thyroid nodule, can achieve the purposes of fast, accurate diagnosis the thyroid nodules. |
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