Sonographic Appearance Of Metastatic Cervical Lymph Nodes From NPC And Predicting Short-term Effect Of Chemoradiotherapy Of These Malignant Nodes By Ultrasonography

Objective:1.To decect the characteristic of metastatic cervical lymph nodes from nasopharyngeal carcinoma(NPC)by ultrasonography and color Doppler flow imaging.2.To observe the changes of these malignant nodes follow-up during therapy period,and to investigate the value of ultrasonography in predicting short-term effect of chemoradiotherapy of metastatic cervical lymph nodes from NPC.Method:36 patients confirmed as nesopharyngeal poorly differentiated squamous-cell carcinoma pathologically by biopsy were included,and their 69 metastatic cervical lymph nodes were studied by tow-dimensional ultrasonography and color Doppler flow imaging with a 5-12 MHz high-resolution linear transducer(Philips iU 22,Netherlands). The characteristic of malignant nodes,such as position,shape,size, long/short axis ratio(L/S),inner echo,vascular distribution,blood supply grading,peak systolic velocity(PS)and resistivity index(RI),were recorded before treatment.In 25 patients,all of whom underwent chemoradiotherapy,their 43 lymph nodes were examined repeatedly after chemotherapy and approximately every 2 weeks during radiotherapy.And these follow-up malignant nodes were divided into groups according to the size and the pattern of blood flow change respectively,then the regression rate of metastatic nodes of different groups was compared. Results:1.Before treatment,the majority of malignant nodes(61/69) from NPC were hypoechoic,round or elliptical,and the minority(8/69) with illdefined borders.The mean L/S was 1.95±0.54,and 41(59.4%)of 69 malignant nodes had an L/S less than 2.In most malignant nodes,the central echogenic hilum was absent.But displaced echogenic hilum, intranodal demarcated echogenic focus which suggested coagulation necrosis and intranodal cystic necrosis was observed in partial malignant nodes.Color Doppler flow signals were scored asⅡ～Ⅲin 57(85.5%) of 69 malignant nodes,and the malignant nodes of size-more-than 4cm group had more abundant blood supply.The mean PS was 25.3±15.4 cm/s,and the mean RI was 0.715±0.142.2.During treatment,the regression rate of short axis was bigger than that of long axis.After radiotherapy,the blood supply decreased and the mean RI was 0.440±0.272(0.711±0.142 before treatment).12(80%)of 15 malignant nodes in size-bigger-than 4cm group showed good regression, while 13(46.4%)of 28 in size-shorter-than 4cm group showed good regression.But no statistical significance was observed in regression rate of different blood flow grades.The regression rate in the blood-flow-decreasing group was bigger than that in the blood-flow-increasing group and the same-blood-supply group.Conclusion:1.On graspable sonography,metastatic cervical lymph nodes from NPC are usually hypoechoic with various apperences.On color Doppler,metastatic nodes usually show abundant blood supply and tend to have high RI and PS value.During treatment,the regression rate of short axis was bigger than that of long axis,and an increase in blood flow 2 weeks after irradiation(20Gy)was observed in partial malignant nodes,but after radiation therapy a reduction in intranodal vascularity was found in all metastatic nodes.2.These malignant nodes,in which blood flow markedly decreased 2 weeks after irradiation,has quicker regression rate.This study suggests that ultrasonography maybe have a role in the follow-up of metastatic nodes from NPC receiving chemoradiotherapy.The size and the blood flow of metastatic nodes before therapy and the changes of blood flow in the therapy period may play a role in the evaluation of nodal short-term response to chemoradiotherapy.