健康儿童前颅底骨化年龄的CT研究

Study on CT appearance of ossification age of the normal anterior skull base in healthy children

目的 探讨健康儿童前颅底在影像上的骨化规律及完全骨化的初始年龄,为临床评估儿童前颅底病变提供帮助.方法2014年2月至2016年3月间回顾性搜集于天津市儿童医院行螺旋CT检查的204例患儿的临床及影像学资料,年龄0-16岁,中位年龄2岁2个月.在Philips ISPSERVER工作站对CT轴面原始数据分别进行矢状和冠状面重建.2名高年资影像科医师分别对重建图像进行径线测量,测量指标包括前颅底的长度、宽度,未骨化区的长度、宽度并计算未骨化率.正态分布资料以x^ˉ± s表示,偏态分布资料以中位数（四分位数间距）表示,采用Spearman相关对符合线性分布的测量指标和年龄进行相关分析,对于不符合线性分布的测量指标,首先进行log转换使其符合线性分布,再与年龄进行Spearman相关分析.结果 所有儿童前颅底平均长度为（58.7±15.6） mm,平均宽度为（15.2±6.8）mm;前颅底未骨化区域长度为2.2（10.8）mm,宽度为2.5（7.5）mm;矢状面和冠状面前颅底平均未骨化率分别为0.04（0.22）、0.17（0.60）.点线图显示前颅底长度、宽度和年龄均呈明显正相关（r值分别为0.935、0.896,P〈0.001）,而前颅底未骨化长度和宽度及相应未骨化率与年龄均呈明显负相关（r值分别为-0.840、-0.729、-0.887、-0.833,P〈0.001）.前颅底未骨化区在出生后6个月内迅速骨化：出生后1个月时,矢状面平均未骨化率为0.58,至出生后6个月时,矢状面平均未骨化率已降至0.15.出生后5个月时,所有儿童的前颅底至少达到50%骨化;1岁4个月时,所有儿童的前颅底至少达到80%骨化;在3岁9个月时,所有儿童前颅底完全骨化.结论 儿童前颅底骨化年龄具有一定规律可循,3岁9个月可能是CT影像上前颅底完全骨化的初始年龄.

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.