| Background and Objective:With the rapid development of ultrasound technology, more and more thyroid microcarcinoma are checked out. Coupled with a general increase in people’s health awareness, the number of thyroid examination are much more, too. Epidemiology reported, the detection rates of thyroid nodules may be touched by doctors are 5% for women, and 1% for men are. If combing with the high-resolution ultrasound, the detection rate is as high as 19% to 67%. Such a high incidence of thyroid nodules put forward a acid test for us to find a clinical reasonable approach.As a preferred method of examination of the thyroid, ultrasound has become the main method of screening for thyroid nodules for its convenient, economical, and high resolution. However, due to the cross morphological characteristics of benign and malignant thyroid nodules, and the influence of clinical experience, different ultrasound doctors give different judgment of whether a nodule is benign or malignant, especially for thyroid nodules of TI-RADS 4. Given these limitations of conventional ultrasound, we need a new technology to provide a new way to differentiate benign and malignant thyroid nodules, which may improve the diagnostic accuracy of conventional ultrasound and supply more information but for the morphological characteristics.Real-time shear wave elastography technique(SWE) is a new ultrasound imaging technology developed in recent years. It offers the information of weather a nodule is benign of not by reflecting the hardness of nodules, which was showed by Young’s modulus of nodules. It may greatly compensate the information of hardness to morphological diagnostic of conventional ultrasound, which has a very broad practical value and application prospects.Therefore, with the pathological results as the gold standard, we applied SWE for thyroid nodules of TI-RADS 4 and explore the diagnostic efficacy and other values for conventional ultrasound. Materials and Methods:1.Part I: 237 patients were collected from September 2013 to December 2014 in our hospital of with thyroid nodules and 151 patients with single solid thyroid nodules of TI-RADS 4 were selected. SWE was performed on them. Then we explored the diagnostic value of different SWE parameters, such as the mean, the max and the minimum Young’s modulus on thyroid nodules.2.Part II: Select the 151 patients with thyroid nodules of TI-RADS 4 above. By comparing the mean Young’s modulus(Emean)with threshold value, define the nodule higher as 4b and the lower as 4a. Using the Kappa for the interobserver and intraobserver variations. Similarly, two radiologists subdivided the category 4 into 4a and 4b according to conventional TI-RADS criterions, then obtain the interobserver and intraobserver variations too.3.Part III: 151 patients above was distinguished to TI-RADS 4a and 4b according to conventional ultrasound with the diagnostic criteria of Horvath. By comparing Emean with threshold value, 4a nodules with Emean lower than threshold was defined as TI-RADS 3, which means as short-term follow-up nodules. 4b nodules with Emean higher than threshold as TI-RADS 5, means surgical treatment nodules. Diagnositic performances were analysed before and after modulation. Results:1.The Emax, Emin and Emean of benign thyroid nodules were(55.66±16.61) k Pa,(8.42±5.94) k Pa, and(29.45±11.58) k Pa respectively. And the Young’s modules for malignant nodules were(75.23±21.93)k Pa,(9.65±6.41) k Pa and(51.76±19.47) k Pa respectively. The Emean and Emax between benign and malignant thyroid nodues were statistically significant(P = 0.000), while there was no difference for Young’s modulus of the minimum(P = 0.470). AUC of Emax and Emean were 0.767 and 0.864 respectively. And the diagnose value of Emean was higher than Emax(P<0.05).2.For SWE standard, the intraobserver and interobserver variations were good(k=0.839,0.826,0.826 and 0.813,respectively). For conventional TI-RADS standard, experienced radiologists showed a good degree of agreement(k=0.827), but the inexperienced one just substantial(k=0.612).And the interobserver agreements were just moderate(k=0.454 and 0.427).3.The threshold value was 38.37 k Pa. In 72 cases of 4a grade nodules, Emean of 56 cases were lower than the threshold of which 49 were benign and 7 were malignant. In 79 cases of 4b grade nodules, Emean of 46 cases were higher than the threshold, including 5 cases of benign and 41 cases of malignant. Conclusion:1.The Emean and Emax may both help to differentiate the benign and malignant thyroid nodules. And the value of Emean was higher than the Emax.2. SWE, as the criteria to subdivide the TI-RADS 4 into 4a and 4b, may increase the consistency of diagnosis.3. SWE can significantly decrease the rate of biopsy of TI-RADS IV diagnosed by conventional ultrasound by eliminating the benign and malignant nodules. |
PDF Full Text Request