Clinical Research Of Contrast-enhanced Ultrasound Sonography In Evaluation The Effects On Irradiation Radiation To Residual Cervical Lymph Nodes To Patients With Nasopharyngeal Carcinoma

Objective The advantage of contrast-enhanced Ultrasound/ sonography was taken to reveal the microcirculation of lymph nodes and to detect the characteristics of residual lymph nodes in morphology and dynamic microcirculation of angioarchitecture. After compared with pathologic results, the clinical value of high-frequecy ultrasonography and the technique of gray-scale contrast-enhanced sonography were evaluated in the effects of radiotheraphy to metastasis of cervical lymph nodes in patients with nasopharyngeal carcinoma and provided theory recording for future treatment.Methods Among 78 consecutive patients with nasopharyngeal carcinomas, 27 cases with 68 enlarged cervical lymph nodes that clinically suspected to be malignant were prospectively examined by ultrasound after irradiation. According to the examination of conventional high-frequency sonography, the gray-scale contrast-enhanced sonography and comparison with the results of pathologic biopsy, the patients were divided into 2 groups, residual group with there were still malignant in residual lymph nodes and no residual group with there were no malignant left in residual lymph nodes. Morphology and angioarchitecture such as the longitudinal diameter, the distributional pattern of vascular perfusion and the location of the hilus were used as parameters. According to the incidence of vascular patterns, lymphomatous nodes were described as 4 types: Type I was no vascularity could be identified. Type II vascular signal was located at central part for symmetric vessel in hilus or vessel was aligned along longitudinal diameters when hilus couldn't be recognized. Type III was vascular signal distributed in peripheral range and not related with the echogenic hilus. Type IV was vascular signal concentrated in the echogenic hilus and peripheral range in network. The gray-scale contrast-enhanced sonography was performed after intravenous injection, the lymph nodes were classified into 3 types: type A was scarce intranodal enhancement, only capsular was the mild intensified in whole node and the perfusion was in asymmetric. Type B was significantly intensified in the nodal parenchyma and there was not local-low or perfusion defects except middle part of the echogenic hilus presented in irregular image. Type C was intensified in whole nodal parenchyma and it was difficult to differentiated node with the echogenic hilus.The results were analyzed by statistics software of SPSS13.0.χ~2 test was used in vascular pattern of lymph nodes. In the quantitative analysis, the results were expressed as means±standard (s) and analyzed between groups with non-paired t-test. Significance was declared at the P<0.05.Results Examination of high-frequency ultrasonography showed the longitudinal diameters in residual group were higher and the shrink rates were lower than that of no residual group. The vascular speed in the residual nodes was much more quickly and the percent of absent or aberrant hilus were significant higher. There was statistical difference between two groups. The residual nodes were identified as malignancy if vascular pattern was in Type III and IV. Comparison with the results of pathologic biopsy, the accuracy of conventional techniques of high-frequency ultrasound in differentiation between two groups were 87.0% in evaluation of irradiational effects on metastasis of cervical lymph nodes in patients with nasopharyngeal carcinoma.In contrast-enhanced sonography showed enhancement of type C was occupied in 46%, type B in 39% and type A in 15% in residual group. But in no residual group, type C was only in 5%, type B in 25% and type A in 70%. Then, the residual malignant nodes were identified with type B or type C. Comparison with the results of pathologic biopsy, the accuracy of gray-scale contrast-enhanced sonography in differentiation between two groups were 91.2% for in evaluation of irradiation effects on metastasis of cervical lymph nodes in patients with nasopharyngeal carcinoma.Time-intensity curve analysis could reflect dynamic perfusion of lymph nodes. In the curve image, the ascent part was presented in quick-up, then slow down gradually after arrived peak in the two group. Quantitative parameters in time-intensity curve were analyzed, the results indicated there were no difference in (3 value , arrived time(AT) of contrast and time to peak(TTP) between residual group and no residual group. However, the peak intensity (PI) in residual group was significant higher than those of the no resident group (P<0.05).Conclusions With contrast-enhanced ultrasound, it is higher in accurate rate than that of conventional sonography in differentiations of cervical residual lymph nodes in patients with nasopharyngeal carcinoma after irradiation. It can be one of practice examination and have important value in differentiating diagnosis by detecting the characteristics of morphology and angioarchitecture such as the longitudinal diameter, intranodal echogenicity, echogenic hilus and vascular pattern.