Echography of metastatic nodes treated by radiotherapy

The purpose of this study was to evaluate whether the ultrasonographic appe arances of nodal metastases in nasopharyngeal carcinoma (NPC) revert to nor mal after radiotherapy. Serial ultrasonography was performed in 18 patients with palpable nodal met astases in the neck who underwent radiotherapy for NPC. All patients had a pre-radiotherapy baseline and another study at least one year after radioth erapy. The largest node in each patient was evaluated for any change in the ultrasonographic features following radiotherapy. One year after radiotherapy nodes returned to normal size for their respect ive areas, the shape of the node and the echogenic hilus also reverted to n ormal. However, the nodes are more echogenic than nodes in normal subjects. This distinguishes these nodes from nodes not affected by radiotherapy. Th e histological basis for this observation is presumed to be the result of f ibrosis. At first glance the post-radiotherapy nodes may resemble normal nodes, howe ver subtle changes within the node and adjacent soft tissues can be recogni zed on ultrasonography. During long-term follow-up, the appearance of nodes at sites previously uninvolved or any change in the appearance of nodes sh ould alert the sonologist to the possibility of recurrence.