Magnetic resonance imaging patterns of the development of the sphenoid sinus: a review of 800 patients.

Accurate knowledge of age-related development and pneumatisation of the paranasal sinuses has become an important issue in diagnosing paranasal sinus diseases in infants and young adults. Magnetic resonance imaging (MRI) has the potential to assess bone marrow conversion and pneumatisation of the paranasal sinuses. We retrospectively reviewed 800 children aged 0-14 years undergoing brain MRI for various indications. T1-weighted sagittal and T2-weighted axial scans were evaluated for bone marrow conversion and development of pneumatisation of the sphenoid sinus. The sphenoid sinus had a uniformly low signal intensity on T1-weighted images in all children less than four months old. Signal intensity began to change to hyperintense marrow at the age of four months. Onset of pneumatisation was observed in 19% at the age of 12-15 months. Pneumatisation was complete in all patients older than 10 years. In conclusion, these data can be used as baseline standards of normal age-related development of the sphenoid sinus and can be of great value for the diagnostic and therapeutic management of pathologic conditions of the child's sphenoid sinus and its surrounds.