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 development of the sphenoid bone, but scant detailed volumetric data regarding this process, as it evolves from childhood to old age, exist, Using helical CT scanning, we assessed age-related volumetric changes of the sphenoid sinus, METHODS: We used CT data obtained from 214 patients (age range, 1 to 80 years; 111 male and 103 female subjects) with middle or inner ear disease to assess the extent of sphenoid aeration, We also determined volumes of the sphenoid sinuses on 1.0- or 1.5-mm reformatted images by integrating the sinus air (less than or equal to-900 HU) area. RESULTS: Sphenoid sinus aeration began as a doublet in the anterior boundary of the sphenoid bone by the age of 5 years, with patients more than 6 years old exhibiting varying degrees of aeration, The aeration on both sides continued to expand until the third decade of life. The maximum average volume 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 level. The aeration of the peripheral portions of the sphenoid bone, such as the pterygoid process, anterior clinoid process, and dorsum sella, occurred 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 scanning revealed age-related expansion and reduction in aeration.