Study on CT appearance of ossification age of the normal anterior skull base in healthy children / 中华放射学杂志

ABSTRACT

Objective To explore the age at which the anterior skull base is fully ossified as assessed on CT examinations in healthy children and it may be helpful for clinical assessment of anterior cranial lesions. Methods This was a retrospective review of the CT examinations of 204 patients (age range 0-16 years old, median age 2 years and 2 months) from February 2014 to March 2016 at Tianjin Children's Hospital. The raw images were reformatted as the sagittal and coronal images at Philips ISPSERVER workstation.Measurements of the length and width of the anterior skull base and the presence and rate of the anterior unossified portion were determined by 2 radiologists.Skewed distribution data were indicated with median (interquartile range). Spearman correlation test was used to analyze the correlation between the measurements and age, respectively. If data were not normally distributed, they were first converted by log transformation.The linear graph was used to evaluate the ossified pattern of anterior skull base in healthy children.Results The average length and width of anterior skull base was(58.7±15.6)mm and (15.2±6.8) mm, respectively. The length and width of unossified portion and corresponding unossified rate were 2.2(10.8)mm,2.5(7.5)mm,0.04(0.22)and 0.17(0.60).The linear graph showed that the length and width of the anterior skull base were positively correlated with age(r=0.935,0.896,P<0.001),while the length,width and corresponding unossified rate of unossified portion were negatively correlated with age(r=-0.840,-0.729,-0.887,-0.833,P<0.001).The unossified portion ossified progressively and rapidly at the first 6 months after birth.The average unossified rate of length was 0.58 and 0.15 in the 1stand 6thmonth, respectively.All children had at least 50% and 80% ossification of anterior skull base at the age of 5 months and 16 months, respectively. The anterior skull base was fully ossified at 45 months in all of our cases. Conclusions There is a certain rule of ossification in anterior skull base for healthy children.The anterior skull base may be fully ossified by 45 months after birth on CT imaging.