[Comparative study on the display ability of CBCT and MSCT in vestibular aqueduct]

Objective: To compare the ability and visibility of cone-beam CT and MSCT in showing vestibular aqueduct. Methods: An experimental anatomical study which from June 2017 to August 2017 was performed on 76 temporal bones from 38 human cadavers with unknown clinical history. They all underwent CBCT and MSCT and all images were unified and standardized. The standard position was oblique sagital reconstruction.The length of the vestibular aqueduct, the midpoint and the external aperture width were measured on the standard position. The internal aperture, isthmus and proximal portion of the vestibular aqueduct on the images of the two kinds of equipment were evaluated. The measurement results of the two devices and image quality of the vestibular aqueduct were compared. Results: There was no significant statistical difference between the results of the measurement of CBCT and MSCT(P>0.05). In CBCT images, the total display rate of internal aperture was 77.6%(59/76), and the clearly display rate was 81.4%(48/59). The total display rate of the proximal portion of vestibular aqueduct was 57.0%(45/79), and the clearly display rate was 60.0%(27/45). The total display rate of isthmus of vestibular aqueduct was 59.2%(45/76), and the clearly display rate was 60.0%(27/45). In MSCT images, the total display rate of was 46.1%(35/76), and the clearly display rate was 60.0%(21/35). The total display rate of 5 of the proximal portion of vestibular aqueduct was 56.6%(43/76), the clearly display rate was 46.5%(20/43). The total display rate of isthmus of vestibular aqueduct was 68.4%(52/76), and the clear display rate 36.5%(19/52). There was significant statistical difference between the CBCT and the MSCT (P<0.05) in displaying of internal aperture of vestibular aqueduct. Conclusion: Compared with MSCT, the image of vestibular aqueduct obtained by CBCT can meet the diagnostic requirements and CBCT have better visibility in showing some subtle structures of vestibular aqueduct than MSCT.