Volume quantification of healthy paranasal cavity by three-dimensional CT imaging

The volume of the air cavities in the paranasal sinuses is, even at present , not only the simplest but also the most important index employed in the e valuation of the paranasal sinus. We have measured the size of the paranasa l cavities in 20 healthy Japanese subjects by reconstructing three-dimensio nal (3-D) computed tomography (CT) images. To avoid any bias in determining the cavity margin, we first measured bilateral maxillary sinuses of a maca que both by silicone injection and by 3-D reconstruction. Then the CT value for 3-D reconstruction was determined by comparison with the volume measur ed by direct injection. Each sinus of the healthy volunteers was then measu red by 3-D reconstruction imaging. Paranasal sinuses were, individually and on the whole, apparently larger than previously reported: 90.1 mi in males and 72.5 mi in females, on average. Comparing with other body size indices , the increment of the size was quite apparent and the lower prevalence of sinusitis was assumed to play a role in this increased volume of paranasal sinuses in the modern Japanese population.