MAGNETIC-RESONANCE ASSESSMENT OF AGE-RELATED DEVELOPMENT OF THE SPHENOID SINUS

Magnetic resonance images of the sphenoid sinus in 401 patients under 15 years old were reviewed to establish normal age-related standards. T-1-weighted sagittal and T-1-weighted axial scans were evaluated for bone marrow conversion, development of pneumatization, spatial enlarge ment and septation of the sphenoid sinus. The sphenoid sinus had a uni formly low signal intensity (red bone marrow) on T-1-weighted images i n all children less than 4 months old. Signal intensity changes from h ypointense to hyperintense (bone marrow conversion) started at the age of 4 months. Onset of pneumatization was observed in 12% of the patie nts at age 13-15 months. By age 43-48 months, 85% of the patients show ed pneumatization of the anterior part of the sphenoid bone. Pneumatiz ation was complete in all patients older than 10 years. Enlargement of the sinus showed a characteristic profile in each dimension. Median s eptation was observed irregularly with age, with a maximum of 77%. Sep tum variants were noticed between 4.5% and 20%. Because paediatric sin us disease is a challenging problem in children, these results may be useful as baseline standards of normal age-related development of the sphenoid sinus during childhood.