NEOPLASTIC FIXATION TO THE PREVERTEBRAL COMPARTMENT BY SQUAMOUS-CELL CARCINOMA OF THE HEAD AND NECK

OBJECTIVE. The purpose of this study was to determine the accuracy of MR imaging in determining fixation of squamous cell carcinomas to the prevertebral space. MATERIALS AND METHODS. MR images of 15 patients wi th large pharyngeal carcinoma (n = 13) or laryngeal carcinomas with ph aryngeal extension (n = 2) were retrospectively reviewed independently by two head and neck radiologists who were unaware of the surgical fi ndings. MR images were evaluated for four criteria in the prevertebral longus muscle complex: muscle concavity, irregular tumor-muscle inter face, T2 hyperintensity, and enhancement. All patients underwent panen doscopy where fixation or mobility of the tumor relative to the prever tebral fascia was assessed by manual manipulation. Tumors in six patie nts were fixed to the prevertebral space and inoperable. In nine patie nts whose tumors were not fixed, open neck explorations were performed ant tumors were resected in seven patients. MR findings were compared with panendoscopy in all patients and with intraoperative assessment in nine patients. RESULTS. Eleven of 15 patients had at least two of t he MR imaging criteria present. None of the MR findings were both sens itive and specific for tumor fixation. Although muscle concavity and e nhancement each had a sensitivity of 88%, both criteria suffered from low specificity (14% and 29%, respectively). An irregular tumor-muscle interface and muscle T2 hyperintensity were criteria that suffered fr om both low sensitivity and specificity. Accuracy of the imaging crite ria independently ranged from 53% to 60%. CONCLUSION. Although abnorma l muscle contour, T2 hyperintensity, and enhancement are frequently pr esent in neck carcinomas that are fixed to the prevertebral space, the se findings may also be present in patients in whom the tumor is mobil e and resectable. MR imaging may not be able to differentiate between neoplastic fixation and nonneoplastic changes in the prevertebral spac e.