Objective: To study the normal anatomy of aditus of antrum and antrum on the high-resolution CT (HRCT) and the three-dimensional reconstruction, testing the normal range. And comparison was carried out according to the age, sex and side.
Method: Ninety cases were randomly selected without ear lesions. Scanning were taken in sagittal, transverse and coronal planes on HRCT respectively. The structure of aditus and antrum was displayed by three-dimensional reconstruction. The left-right distances and up-down distances, antero-posterior distances were measured and analyzed.
Result: The image of antrum varied with age, while aditus remained constant on the HRCT and the three-dimensional reconstruction. The average of left-right distance of aditus was (5.19 +/- 1.39) mm, and the average of up-down distance of aditus was (5.74 +/- 1.16) mm. The average of left-right distance of antrum was (8.27 +/- 1.41) mm (<6 years old) and (5.41 +/- 1.32) mm (> or = 6 years old). The average of up-down distance of antrum was (11.78 +/- 1.65) mm (<6 years old) and (9.91 +/- 2.04) mm (> or = 6 years old). The average of antero-posterior distance of antrum was (12.25 +/- 1.23) mm (<6 years old) and (10.05 +/- 1.69) mm (> or = 6 years old). No statistically significant differences were seen in left-right distance of aditus by age, sex and side (P > 0.05). Significant differences in up-down distance of aditus was found between male and female, and the distance in male was greater than that in female (P < 0.05). Statistically significant differences were seen in left-right distance and up-down distance, antero-posterior distance of antrum by age (P < 0.05), but no statistically significant differences by sex or side (P > 0.05).
Conclusion: Imaging of aditus ad antrum is relatively constant in the normal persons, while the aditus is more diverse. Significant gender differences were seen in up-down distance. There were significant differences in left-right distance, up-down distance, and antero-posterior distance of aditus among all age groups.