Functional MR imaging of the eustachian tube in patients with clinically proven dysfunction: correlation with lesions detected on MR images.

Objectives: To visualise the function of the Eustachian tube by MRI and assess the effect of surrounding lesions.

Methods: Using 1.5 T MRI, 32 Eustachian tubes of 16 patients with clinically proven dysfunction (clinical symptoms, such as autophonia and fullness and non-opening at tympanometry) were investigated. For depiction of the anatomy and associated abnormalities, coronal and axial T2-weighted turbo spin echo sequences and a T1-weighted-2D-gradient echo sequences were acquired. Eustachian tube opening was analysed with real time turbo-gradient echo sequences during a Valsalva manoeuvre.

Results: Dysfunction, that is, failure of opening of the Eustachian tube as shown by MRI, correlated in all patients with tympanometry. Lesions detected included nasopharyngeal carcinoma in 4 patients. Mucosal swelling in the paranasal sinus was present in 9 patients. One patient had postoperative defects. In two patients both pharyngotympanic tubes did not open although no structural abnormalities could be depicted.

Conclusions: The opening of the Eustachian tubes during the Valsalva manoeuvre is assessable on MRI. Failure of opening may be due to swelling of the mucosa and may be also associated with tumours. MRI assessment may be helpful in patients with chronic otitis media, where the information about tubal function is important in preoperative planning.

Key Points: •Eustachian tube opening during Valsalva manoeuvre can be visualised with MRI •Lesions hampering tubal opening can be delineated at the same MRI examination •Functional MRI of the Eustachian tubes might determine the cause of dysfunction.