Sonographic Findings of the Neopharynx after Total Laryngectomy: Comparison with CT

Abstract

BACKGROUND AND PURPOSE: To our knowledge, sonographic findings in the neopharynx have not been well characterized. We describe our results and assess the role of sonography versus CT in patients who have undergone total laryngectomy.

METHODS: We examined 25 patients (24 men and one woman; 44–78 years old) who had had a total laryngectomy. Sonography (with a 10-MHz transducer) and contrast-enhanced CT were performed in all patients. We evaluated the normal shape of the neopharynx and assessed the accuracy of sonography versus CT in detecting tumor recurrence in the neck.

RESULTS: The neopharynx appears as a round or ovoid structure on imaging studies. On sonograms, the neopharyngeal wall has five layers of alternating echogenicity: an innermost hyperechoic layer of superficial mucosa, an inner hypoechoic layer of deep mucosa, a middle hyperechoic layer of submucosa, an outer hypoechoic layer of muscle, and an outermost hyperechoic layer of adventitia. On CT scans, the neopharynx appears as a three-layered structure, with an inner hyperdense layer of mucosa, a middle hypodense layer of submucosa, and an outer isodense layer of pharyngeal constrictor muscles. Nine pathologically proved recurrences were found: three local recurrences, one local recurrence with lymph node metastasis, and five cases of lymph node metastasis only. One instance of false-negative lymph node metastasis was seen at sonography and one case of false-positive local recurrence was seen at CT.

CONCLUSION: The neopharynx has a unique sonographic appearance, and this imaging technique is useful for detecting local tumor recurrence in the neopharynx in patients who have had a total laryngectomy.