PurposeTo investigate the growth pattern of temporal bone pneumatization (TBP) in consecutive age groups from birth to 18years old using 3D air-density reconstruction of high-resolution CT (HRCT).MethodsA total of 570 patients under 18years old who performed temporal bone HRCT and with no structural abnormalities on both sides were included. Nineteen groups were created to represent consecutive ages, with 15 males and 15 females in each group. Volume rendering of air density was performed using a segmentation threshold of -200 HU to obtain TBP volume of each side. The differences in TBP between the sides, sexes, and ages were statistically analyzed.ResultsThe mean volume of TBP was measured as 1.170.44ml in patients less than 1 year old and 6.81 +/- 1.93ml as adult size. High consistencies of TBP volume between different sides or sexes were found in most of age groups. Significant differences were shown between sides only in 9- and 11-year-old female groups (p(9)=0.031, p(11)=0.016) while between sexes only in 6- and 16-year-old groups (p(6)=0.001, p(16)=0.043), although the volume was larger in all the male groups older than 6years. The curve drawn by the mean volume in consecutive age groups showed that TBP continued to grow linearly in both males and females until they reached 14years old. The corresponding linear regression equations were as follows: y(m)=1.553+0.370x, (x14 years, R-2=0.596); y(f)=1.561+0.304x, (x14 years, R-2=0.565).Conclusion The TBP volume shows a linear growth pattern from birth until reaching adult size after 14years old.