[Computed tomographic volumetry of the pneumatic system of the ear. Comparison of normal subjects and patients with ear diseases].

The volume of the pneumatised portion of the ear was determined by computed tomography in 235 patients. Amongst the 470 ears examined, 320 had no disease in the ear, nose or throat. Normal pneumatisation of the ear can be quantified by CT and strict correlation has been demonstrated between the air content and age from ten to 17 years. Chronic inflammatory processes of the middle ear occurring during childhood interfere with pneumatisation on one or both sides. The most severe failure of pneumatisation occurs with congenital abnormalities of the ear, most cases never showing significant pneumatisation. Chronic infection of the tonsils or adenoids causes much less interference with pneumatisation.