Study On Normal Costal Cartilage By 64-slice Spiral CT

Objective:To prospectively, explore the scanning and post-processing methods of costal cartilage using 64-slice spiral CT, to investigate the differences of the image quality among post-processing methods including VRT, MIP, MPR(CPR), Raysum and SSD, and to analyze the sexual differences and age-correlation of ossified costal cartilage.Materials and Methods:Two hundreds and seventy cases(M135, F135,10-year as a group,9 groups each) without thoracoabdominal trauma, chronic cardiopulmonary disease or tumor were scanned by 64-slice CT using isotropic parameters. All the datas were transported to the workstation for post-processing. (1) The image quality of VRT, MIP, Raysum, MPR(CPR) and SSD displaying cartilaginous part, ossified part, costochondral junction, sternocostal joint and the whole view were compared respectively. (2) Ossification pattern was divided into peripheral(P), central(C), mixed(M) and indifferent(Ind). The mixed pattern included peripheral-dominant(M-P), central-dominant(M-C) and pure-mixed(M-Pp). The differences of ossification pattern between male and female were compared. (3) The correlation between age and ossification occurrence rate of 12 costal cartilage was studied. The extent of ossification was evaluated by ossification score, and correlation between age and ossification score was analyzed.Results:(1) MPR(CPR) was better than VRT, MIP, Raysum, and SSD in displaying cartilaginous part, ossified part, costochondral junction, stemocostal joint(P<0.05). There was no significant difference among VRT, MIP and Raysum in displaying cartilaginous part and the whole view of costal cartilage(p>0.05). MIP was better than VRT and Raysum in displaying ossified part(P<0.05). VRT and Raysum were better than MIP in displaying costochondral junction and sternocostal joint(P<0.05). SSD was worse than MPR(CPR), VRT, MIP and Raysum in displaying the datail and the whole view of costal cartilage(P<0.05). (2) P type and M-P type revealed in male were more than in female(P<0.05). C type, M-C type and M type revealed in female were more than in male(P<0.05). There was no significant difference between male and female in Ind type. (3)Ossification started in the 2nd decade. Ossification occurrence rate of 12 costal cartilages increased with age. High correlation between age and ossification score was shown(r=0.733).Conclusion:(1) The scanning parameters and post-processing parameters influence image quality. (2) MPR(CPR) is the best post-processing method in displaying cartilaginous part, ossified part, costochondral junction, sternocostal joint of costal cartilage. VRT, MIP and Raysum have good image quality in displaying the whole view of costal cartilage. VRT is vivid, and MIP has high sensitivity in revealing ossified part. SSD should be abandoned for its bad image quality. (3) There exists sexual difference in ossification pattern of costal cartilage. The male has more P type and M-P type, and the female has more C type, M-C type and M type. (4)Ossification started in the 2nd decade. Ossification occurrence rate and ossification degree increase with age. (5) The pattern and degree of costal cartilage ossification help to infer sex and age.