The usefulness of Valsalva computed tomography as an assessment tool for the Eustachian tube

Abstract

To determine the usefulness of 'computed tomography (CT) with Valsalva maneuver (VM)' (Valsalva CT) for localizing lesions of the eustachian tube (ET) and identifying characteristics of ET dysfunction (ETD). In this case-control study, 12, 17, and 25 patients with obstructive ETD (OETD), patulous eustachian tube (PET), and conductive hearing loss (control), respectively, underwent Valsalva CT in the supine position. The visualized length to total length ratio of the cartilaginous ET (VTRET) with and without VM were compared in the three groups. In the OETD group, obstructed areas of the ET were identified on multiplanar reconstructed images. VTRET without VM in the PET group was significantly higher than that in the control and OETD groups (p-values, 0.003 and 0.007, respectively). However, there was no significant difference between the control and OETD groups (p=0.053). VTRET with VM in the PET group was significantly higher than that in the other two groups (p<0.001), whereas that in the control group was significantly higher than that in the OETD group (p<0.001). In the OETD group, the obstructed area was clearly identified, and there were one, one, six, and eight patients in the isthmus; bony portion and isthmus; bony portion, isthmus, and cartilaginous portion; and isthmus and cartilaginous portion subgroups, respectively. Valsalva CT is particularly valuable as a visualization assessment tool for identifying obstructed areas in the OETD. It may help future research of disease-specific mechanical characteristics of the ET on controlling pressure variables.