Changes of visualised Eustachian tube lengths by age and position: Radiologic study in sitting and supine positions using cone beam and conventional CT

• DOI: 10.1111/coa.13342
• Publication Date: 2019-04-20T12:04:31Z
• Authors: Seung Cheol Ha; Jin Baik; Hyo Jung Park; Hyun Moon; Byung Chul Kang; Jun Woo Park; Woo Seok Kang; Hong Ju Park
• Keywords: Adult; Aged, 80 and over; Male; Sitting Position; Eustachian Tube; Age Factors; Cone-Beam Computed Tomography; Middle Aged; 03 medical and health sciences; 0302 clinical medicine; Supine Position; Humans; Female; Tomography, X-Ray Computed; Aged; Retrospective Studies

AbstractObjectivesPatulous eustachian tube (ET) has been characterised by the visualisation of full‐length ET on computed tomography (CT) results. We wanted to investigate the changes of visualised ET lengths by age in supine and sitting positions.DesignRetrospective study.SettingTertiary care academic referral centre.ParticipantsOne hundred subjects who underwent cone beam CT (CBCT) in a sitting position and conventional CT in a supine position for non‐otitis‐related or dental complaints.Main outcome measuresVisualised ET lengths from the nasopharyngeal orifice measured by different positions and ages.ResultsSubjects did not show visualisation of full‐length ET throughout the study. The visualised ET lengths (9.0 ± 2.5 mm) of the CBCT group were significantly larger than those (6.8 ± 2.3 mm) of the conventional CT group (P < 0.0001).Women showed longer visualised ET lengths than men in CBCT group (P < 0.001). The visualised ET lengths of the CBCT group were consistent or slightly increasing as a function of age (P = 0.06); however, the visualised ET lengths of the conventional CT group decreased as a function of age (P = 0.001). The slopes of regression lines of the two groups were significantly different.ConclusionsWhen in the supine position, the ET lengths gradually shortened as the subjects got older, most likely due to venous engorgement and the collapse of surrounding tissues; this finding thus suggests that CT in a supine position is an inappropriate method to diagnose patulous ET. The visualised ET lengths by CBCT in a sitting position were consistent throughout the different ages of the subjects and may be used as a diagnostic test for patulous ET.