Article Figures & Data
Figures
- Fig 1.
Reformatted image of a CT of the temporal bone in the 45° oblique plane, demonstrating the position of the vestibular aqueduct.
- Fig 2.
Planning of the axial reformats based on the sagittal scout image. Axial reformats were obtained parallel to the axis of the cochlea (A). The obtained axial reformat demonstrates the vestibular aqueduct (arrow) (B).
- Fig 3.
Planning of the 45° oblique reformats based on the axial scout image. The 45° oblique reformats were obtained parallel to the plane of the SSC (A). The obtained reformat demonstrates the vestibular aqueduct (arrow) (B).
- Fig 4.
Grading of the aqueductal visibility. In 1 patient, there is a grade 3 well-visualized aqueduct in both 45° oblique (A) and axial (B) reformats. In another patient, the vestibular aqueduct is judged to be grade 2 (thin but visible) in 45° oblique formats (C), and grade 1 (difficult to see/very thin) on axial reformats (D).
- Fig 5.
Measurement of the aqueducts: positioning of the measurement bars at the 2 described levels (midportion of the postisthmic segment and external aperture) in (A) and in axial (B, C) reformats.
- Fig 6.
Diagram demonstrating the plane of the axial image across the vestibular aqueduct on the 45° oblique reformat. A line is drawn connecting 2 points of the lateral semicircular canal. This line demonstrates the obliquity of the axial reformat to the axis of the vestibular aqueduct.
Tables
Subjects Age (y)/Gender Indication for CT Patient 1 11/M Mastoiditis Patient 2 16/M Cholesteatoma Patient 3 9/M Cholesteatoma Patient 4 45/M Cholesteatoma Patient 5 33/F Cholesteatoma Patient 6 19 months/M Cholesteatoma Patient 7 7/F Cholesteatoma Patient 8 10/F Cholesteatoma Patient 9 50/M Conductive hearing loss Patient 10 53/F Rule out semicircular canal dehiscence Patient 11 49/F Rule out semicircular canal dehiscence Patient 12 73/M Malignant otitis externa Patient 13 73/M External auditory canal osteoma Patient 14 45/F Conductive hearing loss Patient 15 20 months/F Cholesteatoma - Table 2:
Visibility grade of 30 vestibular aqueducts viewed by 2 readers on 45° oblique and axial reformats
Visibility Grade Observer 1 Observer 1 Observer 2 Observer 2 45° Oblique Axial 45° Oblique Axial 1 1 (3%) 3 (10%) 1 (3%) 4 (13%) 2 3 (10%) 9 (30%) 6 (20%) 11 (37%) 3 26 (87%) 18 (60%) 23 (77%) 15 (15%) Measurement (mm) Mean ± SD Minimum Maximum Median Width at midportion of the postisthmic segment 0.482 ± 0.098 0.3 0.73 0.455 Width at the external aperture 0.616 ± 0.133 0.4 0.85 0.6 - Table 4:
Comparison of measurements obtained from vestibular aqueducts in axial views (paired Student t test) for both ears
Measurement (mm) Mean ± SD Axial P External aperture 0.616 ± 0.133 0.741 ± 0.200 .006
