Age-related expansion and reduction in aeration of the sphenoid sinus: Volume assessment by helical CT scanning

BACKGROUND AND PURPOSE: Aeration of the sphenoid sinus expands with the dev elopment of the sphenoid bone, but scant detailed volumetric data regarding this process, as it evolves from childhood to old age, exist, Using helica l CT scanning, we assessed age-related volumetric changes of the sphenoid s inus, METHODS: We used CT data obtained from 214 patients (age range, 1 to 80 yea rs; 111 male and 103 female subjects) with middle or inner ear disease to a ssess the extent of sphenoid aeration, We also determined volumes of the sp henoid sinuses on 1.0- or 1.5-mm reformatted images by integrating the sinu s air (less than or equal to-900 HU) area. RESULTS: Sphenoid sinus aeration began as a doublet in the anterior boundar y of the sphenoid bone by the age of 5 years, with patients more than 6 yea rs old exhibiting varying degrees of aeration, The aeration on both sides c ontinued to expand until the third decade of life. The maximum average volu me was 8.2 +/- 0.5 cm(3). Thereafter, the volume decreased gradually, with the average volume in the seventh decade of life being 71% of the maximum l evel. The aeration of the peripheral portions of the sphenoid bone, such as the pterygoid process, anterior clinoid process, and dorsum sella, occurre d predominantly after closure of the spheno-occipital suture, and showed a tendency to recede during aging. CONCLUSION: Volumetric assessment of the sphenoid sinus by helical CT scann ing revealed age-related expansion and reduction in aeration.