64排螺旋CT双下肢血管成像低电压扫描的初步研究

Study of 64 Slice Detector CT with Low Tube Voltage in Lower Extremity

目的探讨低管电压(100 kV)扫描下肢CT血管成像(CTA)的辐射剂量、图像质量。方法将60例行双下肢CTA检查的患者,按随机分配原则分为A、B两组(A组30例,B组30例),管电压分别采用100 kV、120kV,管电流均采用300 mA,采用配对t检验统计分析两组下肢CTA的辐射剂量及图像质量。结果扫描结束后记录A组CT容积剂量指数(CTDIvol)、剂量长度乘积(DLP)分别为20.85 mGy、(2342.78±202.49)mGy·cm,B组分别为33.63 mGy、(3478.72±197.34)mGy·cm。A组CTDIvol、DLP较B组分别降低38%;32.6%,两组辐射剂量指标CTDIvol、DLP差异有统计学意义。两组图像质量均能满足诊断要求,两组图像质量评分差异无统计学意义(t=0.521,P=0.604)。结论 64排螺旋CT下肢血管成像采用低管电压可降低辐射剂量的同时获得符合临床诊断要求的图像。

Objective To evaluate the feasibility of lower extremity CT angiography using a low tube voltage （ 100 kV） and the effects of low tube voltage on radiation dose and image quality. Methods 60 patients received lower extremity CT angiography and were randomly assigned to two protocol groups： protocol A （30/60, scanning with 100 kV and 300 mA ） ; protocol B （30/60, scanning with 120 kV and 300 mA ） , CT image quality and radiation does were compared between two groups, T test was performed to analyze the quality. Results CT dose index（group A ： 20.85 mGy group B ： 33.63 mGy ） and DLP（group A： （2342.78 ± 202. 49 ） mGy · cm group B： （3478.72 ± 197.34）mGy · cm ） were recorded. Compared with protocol B, the CTDIvol and DLP of protocol A were reduced by 38% , 32.6% respectively. There was no significant difference in noise levels among the groups （ P 〉 0.05 ）. Conclusion Lower extremity 64 slice CT angiography with 100 KV can reduce radiation dose and obtain a good image quality.