[Comparative studies of diagnosis with US or CT of the cervical lymph node metastases in head and neck cancer].

ABSTRACT

Correct assessment of lymph node metastasis in the head-neck region is very important for management of head and neck cancer. 233 lymph nodes were removed by radical neck dissection from 12 cases with cancer in the head and neck region, who did not undergo any preoperative treatment, and the materials were histopathologically examined. The histopathological findings were compared with preoperative US and CT findings. Histopathologically, 26 lymph nodes were found positive for metastasis and the remaining 207 lymph nodes, negative. US detected 45 (19%) of 233 lymph nodes before operation, and 40 of the 45 lymph nodes (89% 40/45) were qualitatively correctly diagnosed. CT detected 21 lymph nodes (19%), 16 of which were qualitatively correctly diagnosed (76% 16/21). Of 26 lymph nodes which were histopathologically involved, 19 lymph nodes were correctly diagnosed by US and 11 by CT. Possible reasons explaining the superiority of US to CT in terms of diagnostic reliability are the following 1) US demonstrates more clearly the existence of lymph nodes than CT. 2) US is more reliable for measuring sizes of lymph nodes than CT. In literature, CT has been often reported to be useful to diagnose cervical lymph node involvement in individual cases. However, we insist that it is necessary to diagnose individual lymph nodes strictly for correct assessment of the reliability of image diagnosis.