CT and MRI in the Preoperative Planning of Balloon Dilation of the Eustachian Tube: Literature Review.

Balloon dilatation of the Eustachian tube (BET) is a surgical treatment method for Eustachian tube dysfunction (ETD), which relieves the symptoms in the majority of cases. However, there are potential intraoperative risks associated with BET; the decision-making process with regard to indications for BET is not standardized up to date. The objective of this study was to review the role of computed tomography (CT) and magnetic resonance imaging (MRI) in the preoperative planning of BET. The literature review is based on a database search performed in August 2022. BET is classified into transtympanic and nasopharyngeal. CT of the temporal bone provides good visualization of the site of obstruction, which allows to choose the adequate approach. Transtympanic approach is associated with risks of internal carotid artery damage due to possible carotid canal anomalies. This risk can be prevented with preoperative CT scan of the temporal bone. In case of nasopharyngeal BET, there is no sufficient data considering risks of possible artery damage, although CT can provide accurate measurements of ET. MRI is useful for differential diagnosis of conditions imitating ETD, such as endolymphatic hydrops and nasopharyngeal carcinoma. Thus, it is feasible to perform CT and MRI before BET to personalize the management of ETD patients.