Determination of perineural invasion preoperatively on radiographic images.

OBJECTIVE: Perineural invasion in head and neck cancers has important prognostic implications, and even if clinically silent, can be radiographically evident. This study analyzed the frequency of preoperative diagnosis, radiographic features, and importance of the preoperative diagnosis in treatment planning. STUDY DESIGN: Radiographic studies of 38 patients with histopathologically proven perineural spread from head and neck cancer were retrospectively reviewed and compared with preoperative reports. SUBJECTS AND METHODS: The percent agreement with pathology, kappa values, and 95 percent confidence intervals were determined for relevant nerves. Salient radiographic findings were compared with the contralateral normal side. RESULTS: Preoperative agreement was less than 10 percent for all nerves, and retrospectively was 56 percent for the trigeminal nerve and 40 percent for the facial nerve. Radiographic features included neural thickening and enhancement, and foraminal widening. CONCLUSION: Cancers of the head and neck can spread perineurally. Preoperative radiographic determination, although underreported, is imperative, because diagnosis impacts management and prognosis.