Radiological investigation

Radiological investigation

Computed tomography (CT) scanning of the temporal bones is commonly performed before mastoid surgery to show detailed individual anatomy , as well as alerting the surgeon to anatomical variants. Pus, bone and air are shown well on high-resolution CT ( Figure 51.8 ). Magnetic resonance imaging (MRI) is better than CT at imaging soft tissue (e.g. facial and auditory nerve) and is the best method for imaging tumours of the acoustic nerves ( Figure 51.9 ). Di ff usion-weighted MRI is also commonly used to detect recurrent cholesteatoma.

Figure 51.7 Audiometry. The patient sits in a soundproof room and the audiologist presents sounds at different thresholds and records the responses. Figure 51.8 Computed tomography scan showing a normal left ear. The air- /f_i lled middle ear and the incus and stapes, the semicircular canals and internal acoustic meatus can be seen. In the right ear the entire middle ear and mastoid are opaque and /f_i lled with soft tissue. This is the typical appearance of a cholesteatoma.

Radiological investigation

Computed tomography (CT) scanning of the temporal bones is commonly performed before mastoid surgery to show detailed individual anatomy , as well as alerting the surgeon to anatomical variants. Pus, bone and air are shown well on high-resolution CT ( Figure 51.8 ). Magnetic resonance imaging (MRI) is better than CT at imaging soft tissue (e.g. facial and auditory nerve) and is the best method for imaging tumours of the acoustic nerves ( Figure 51.9 ). Di ff usion-weighted MRI is also commonly used to detect recurrent cholesteatoma.

Figure 51.7 Audiometry. The patient sits in a soundproof room and the audiologist presents sounds at different thresholds and records the responses. Figure 51.8 Computed tomography scan showing a normal left ear. The air- /f_i lled middle ear and the incus and stapes, the semicircular canals and internal acoustic meatus can be seen. In the right ear the entire middle ear and mastoid are opaque and /f_i lled with soft tissue. This is the typical appearance of a cholesteatoma.