THE SPHENOID SINUS DURING CHILDHOOD - ESTABLISHMENT OF NORMAL DEVELOPMENTAL STANDARDS BY MRI

To obtain baseline standards of normal age-related development of the sphenoid sinus during childhood magnetic resonance images of the sphen oid sinus in 401 patients less than 15 years old were reviewed. T1-wei ghted sagittal and T2-weighted axial scans were evaluated for bone mar row conversion, development of pneumatization, spatial enlargement and septation of the sphenoid sinus. The sphenoid sinus had a uniformely low signal intensity (red bone marrow) on T1-weighted images in all ch ildren less than 4 months old.-Signal intensity changes from hypo- to hyperintense (bone marrow conversion) started at age of 4 months. Onse t of pneumatization was observed in 12% of the patients at age 13-15 m onths. By age 43-48 months, 85% of the patients showed pneumatization of the anterior part of the sphenoid bone. Pneumatization was complete in all patients older than 10 years. Enlargement of the sinus showed a characteristic profile in each dimension. Median septation was obser ved irregularly with age, with a maximum of 77%. Septum variants were noticed between 4.5% and 20%. The recognition of this phenomenon may s erve as a reference for evaluating normal and abnormal development of the sphenoid sinus and may be of great value for diagnostic and therap eutic management of pathologic conditions of the child's sphenoid sinu s and its surrounds.