Metastatic adenopathy from nasopharyngeal carcinoma: Successful response to radiation therapy assessed by color duplex sonography

BACKGROUND AND PURPOSE: Although the role of gray-scale sonography for neck nodes is well documented, it plays a limited role in the evaluation of nod al response to treatment. This preliminary limited study sought to determin e color duplex sonographic changes in successfully treated metastatic nodes from nasopharyngeal carcinoma. METHODS: Fourteen patients with nodal metastases from nasopharyngeal carcin oma were studied. A pretreatment sonogram was obtained for all patients. Pa tients were divided into two groups of seven: in one group, repeat sonogram s were obtained 8 weeks after completion of treatment; in the second group, sonograms were obtained 16 weeks after treatment, The features studied inc luded distribution of intranodal vascularity, resistive and pulsatility ind exes, and peak systolic velocity. In 11 patients, follow-up sonograms were obtained 1 year after treatment. RESULTS: The majority (90%) of malignant nodes from nasopharyngeal carcinom a have an increased central and peripheral vascularity, a high resistive in dex (0.8), and a high pulsatility index (1,8), After radiation therapy to t he nodes, a reduction in intranodal vascularity and a statistically signifi cant reduction in the resistive index (0.58 to 0.59) and pulsatility index (0.91 to 0.93) are found. Although a similar reduction in the peak systolic velocity is observed, it is not statistically significant. CONCLUSION: Our preliminary findings suggest that after radiation therapy f or malignant nodes in nasopharyngeal carcinoma, a reduction in intranodal v ascularity is found, and the resistive and pulsatility indexes may return t o benign parameters as early as 8 weeks after completion of treatment.