5mAs低剂量多层螺旋CT在上颌前牙埋伏阻生诊断中的应用

目的探讨低剂量多层螺旋计算机体层成像（MSCT）在上颌前部埋伏阻生牙诊断中的应用。方法 172例患者,采用5mAs低剂量16层螺旋CT检查,CTDIw 1.6mGy。患者佩戴铅帽,颈部及以下使用5mmPb铅衣包裹。采用骨算法重建,横断面层厚1mm,窗宽（WW）5000Hu、窗位（WL）1500Hu摄片,并进行多平面重建（MPR）、齿科软件全景重建、三维表面重建（SSD）及最大密度投影重建（MIP）。结果 172例患者共260颗埋伏阻生牙,单发多见（100/172）,大部分位于牙列唇侧（148/260）,尖牙发生率最高（136/260）,中切牙（96/260）、侧切牙（28/260）发生率依次递减。结论 5mAs低剂量MSCT扫描可以清晰显示埋伏阻生牙形态、大小、内部结构及相邻结构关系,满足临床诊断、治疗需要。

Diagnosis of impacted teeth in anterior maxillary by 5mAs Low Dose MSCT

Objective Discuss the application of 5mAs low dose MSCT in diagnosis of impacted teeth. Methods 172 cases with impacted teeth were studied by 16-slices CT scanner in 5 mAs Scan dose. Multiplanar reformation, dental panorama and 3D reconstruction were done in all cases,Pictures were taken at 5000Hu Window Width and 1500Hu Window Level. Results 172 patients had got 260 impacted teeth,100 cases of them only had 1 imp＇acted tooth. The in- cidence of the impacted maxillary canines is the highest（128/260）, the number of the maxillary central incisor is 96 ,sec- ond incisor is 28/148 teeth of them were on the palate side. Conclusion 5mAs low dose MSCT scan display the internalstructures and adjacency relation of the impacted teeth, meet the clinical requirement？ of diagnose.