Quantitative 3.0T MRI Evaluation of Eustachian Tube Structures in Patulous Eustachian Tube.d

Objectives: The purpose of this study was to quantitatively evaluate the mucosa, cartilage, Ostmann’s fatty tissue (OF), and important surrounding muscles of the eustachian tube (ET) using 3 Tesla magnetic resonance imaging (MRI), and then to compare the results between healthy ears and those with a patulous eustachian tube (PET). Study design: Retrospective review. Patients: Sixty-one normal subjects (control group) and 28 patients with patulous ET (patulous group). Methods: We used oblique axial T2-weighted imaging (T2WI), the oblique axial plane T2 spc_short time inversion recovery (T2_spc_stir), the oblique parasagittal T2WI, and the oblique short axis T2WI sequences and localization methods to examine the mucosa and cartilage of the ET, the surrounding muscles, and OF. The measured structures included the following: (1) mucosa and cartilage of the ET, (2) the tensor veli palatini muscle (TVPM), (3) the levator veli palatini muscle (LVPM), and (4) the OF. Results: There were no significant differences between the patient and control groups in terms of age, sex, mucosa, and LVPM ( P > 0.05). In the PET group, bilateral ET cartilage and TVPM thickness of the caudal areas of the ET were significantly smaller than in the control group ( P < 0.05). OF and the narrowest part of the OF were significantly smaller in the PET group ( P < 0.05). Statistically significant differences were found in thickness of the LVPM, OF, and the narrowest part of the OF according to sex ( P < 0.05); it was thicker in the male participants. Conclusions: MRI evaluation of the ET provided detailed anatomic information about its structure and the surrounding tissues. Abnormal thicknesses of the cartilage, TVPM, and OF were specific imaging features of PET patients.