Petrous Apex Pneumatization on Computed Tomography

Park, Ki Young; Han, Kwang Sik; Park, Myoung Geun; Lee, Jong Sun; Park, Young Min; Yang, Ik

Abstract

BACKGROUND AND OBJECTIVES: The mastoid air cell system has been recognized as an important contributor to the function of middle ear ventilation. And, mastoid pneumatization is thought to be correlated with the petrous apex pneumatization. We attempted a comparative analysis of petrous apex pneumatization and the mastoid portion by using target imaging CT. MATERIALS AND MEDTHOD: Pneumatization of the petrous apex v as investigated in 100 subjects without middle ear disease by computer-assisted digital processing of CT images of' the hone.
RESULTS
The rate of pneumatization of the petrous apex in all subjects was 22% (44/200 ears), and there was no difference in the degree of pneumatization between the left and the right ears or between sexes. In 44 ears that showed pneumatization of the petrous apex, a higher degree of pneumatization was found in larger mastoid cavities, suggesting a correlation between pneumatization of the petrous apex and the pneumatized air cells in other parts of the temporal bone. Pneumatization in all parts of the petrous apex was found in about 5% (2/44 ears), and pneumatization in some parts of the petrous apex eas about 95% (42/44 ears). In the latter cases, there was no difference in the degree of pneumatization between the lower portions of the CT slices and the higher ones. SUMMARY: These results indicate that the effects of pneumatization of the petrous apex must be taken into consideration in studies measuring the gas composition and volume of the middle ear, and in temporal bone peumatization which acts as a pressure buffer in middle ear diseases.