CT Appearance Of The Normal Appendix

Objective:To study the MSCT appearance of the normal appendix with various post-procession techniques. Observe the size, wall thickness, location and contents, and investigate the differences in sex, age, body mass index and abdomen fat volume.Materials and Methods:172 cases were included in our study. All the cases were acquired with plain CT scan and three-phase contrast enhancement CT scan. The scanning slice thickness was 5mm, the reformat slice thickness was 1.25mm, and the interval was 1.25mm. The post-procession techniques of multi-planar reformat and curved planar reformat were performed. Measure the diameter, wall thickness and contents of normal appendix and compare the influence of scanning techniques. slice thickness, sex and age on the detection rate of normal appendix. Abdomen fat volume and BMI were both calculated and analyzed. Results:The detection rates of normal appendix showing in slice thickness of 1.25mm and 5 mm are 93.02% and 81.98%, 93.02% and 95.93% in plain scan and three-phase contrast enhancement,92.16% and 94.29% in female and male,86.67% and 87.88% aged below 30 and above 60. Abdomen fat volume was corrected with BMI (r=0.54,p=0.000).age influences the fat volume and BMI affects the detection rate. The normal appendix diameter is 5.71±1.21) mm, and appendix wall thickness is (2.48±0.69) mm. About 25% of all normal appendix contain contents. Conclusion:The detection of appendix is much better in thinner slice thickness during scanning and post-procession of MSCT. The detection rates of plain scan and contrast enhancement are not statistically significant.But MPR and CPR post-processions aid in it. The detection rate is same in different sexes but different from ages.Fat volume which can be inferred by BMI index is different in ages, which is lower aged below 30 and above 60 and the difference is same as appendix display. The diameter, wall-thickness and location are not influenced by ages and sexes. Some contents including gas, fluid and stone are observed in the normal appendix.