Functional MRI of the Eustachian Tubes in Patients With Nasopharyngeal Carcinoma: Correlation With Middle Ear Effusion and Tumor Invasion

OBJECTIVE. We sought to combine the Valsalva maneuver with MRI to evaluate eustachian tube function in patients with nasopharyngeal carcinoma (NPC) and to correlate the extent of tumor invasion with the presence of middle ear effusion (MEE) and eustachian tube dysfunction (ETD). SUBJECTS AND METHODS. We performed MRI along the lengths of the eustachian tubes, before and after the Valsalva maneuver was performed, in 53 patients with untreated NPC. The images were reviewed by two radiologists. RESULTS. A total of 106 eustachian tubes and middle ears were studied. There was dysfunction in 37 eustachian tubes, which was always ipsilateral to the NPC. There was MEE in 26 ears of 22 patients. In all cases of MEE, there was ipsilateral ETD. ETD was correlated with tumor invasion of the ipsilateral pharyngeal recess (p < 0.001), pharyngeal opening of the eustachian tube (p < 0.001), the cartilaginous eustachian tube (p < 0.001), the eustachian cartilage (p < 0.001), Ostmann fat pad (p < 0.001), the levator veli palatine muscle (p < 0.001), and the tensor veli palatine muscle (p < 0.001). There was a strong correlation between the grade of parapharyngeal space invasion and ETD (r = 0.809; p < 0.001) and MEE (r = 0.693; p < 0.001). CONCLUSION. Combining the Valsalva maneuver with MRI is helpful in assessing the function of the eustachian tube in patients with NPC. The cause of MEE in patients with NPC is dysfunction of the eustachian tube opening, which is associated with tumor invasion around the eustachian tube.