Application of Thin Layer Computed Tomography Scan and Image Reconstruction for Sternal End of Clavicle in Bone Age Estimation

Background The main method of living person's age determination is bone age estimation, which is evaluated by X-ray according to the time sequence of secondary ossification center appearance and epiphyseal closure. Comparing traditional X-ray imaging technique, the CT imaging is more sensitive and clear to show the growth states of ossification centers and epiphyseal. The purpose of the study is to investigate thin layer CT scan and image reconstruction in analyzing the time sequence of secondary ossification center appearance and epiphyseal closure of sternal end of clavicle and to explore its application value in bone age identification. Method 100 Chinese Han teenagers aged from 16 to 26 years old and with normal physical developing, 50 persons for male and female respectively. After CT scanning for the sternal end of clavicle, then, grouping the samples in accordance with bone developing grading method proposed by Schmeling, sternal end of clavicle epiphyseal growth was divided into 4 grades. Results The Max age, Min age, Median age and the 95% reference value range of different grades were calculated by statistical analysis(Table). Mann-Whitney's U-test with P<0.05 revealed that bone age in different developing stages of sternal end of clavicle showed significant difference between the sexes, and the bone developing of the female teenagers is earlier about 1 similar to 2 years than that of male teenagers. Meanwhile, empirical distribution function displayed that 100% of the teenagers with stage 1 for classification of the sternal end of clavicle were under 18 years old, 75% of the teenagers with stage 2 were under 18 years old, 94.5% of the teenagers with stage 3 were over 18 years old, 100% of the teenagers with stage 4 were over 20 years. Conclusion Thin layer CT scan and image reconstruction may be expected to become more sensitive and reliable technology in bone age identification.