等中心扫描联合AIDR3D重建在降低CCTA成像辐射剂量中的应用价值

The application value of isocenter scanning combined with AIDR-3D reconstruction in reducing the radiation dose of CCTA imaging

目的:探讨等中心320排CT扫描联合AIDR3D重建在降低冠状动脉CT血管成像(CCTA)辐射剂量中的价值。方法:将108例怀疑冠心病行CCTA检查病人随机平均分为A、B、C组,扫描管电压均为120 kV。A组常规扫描体位,管电流为智能毫安;B、C组等中心位置(心脏位于CT机架孔的中心),管电流分别为智能毫安的90%、60%。A组行滤波反投影法重建和AIDR3D重建分别得到Af、Aa组,B、C组行AIDR3D重建,比较Af、Aa、B、C组图像的噪声、信噪比(SNR)、对比信噪比(CNR)、主观图像质量及辐射剂量(ED)。结果:辐射剂量按A、B、C组顺序依次降低(P<0.01);4组主观图像质量评分显示,Af组评分低于其他3组(P<0.01),其他3组评分差异无统计学意义(P>0.05)。4组客观图像质量的比较显示,噪声方面,Af组最高(P<0.01),其次为C组(P<0.01),Aa和B最低(P<0.01);SNR和CNR两指标方面规律一致,均为Aa和B组最高(P<0.01),其次为C组(P<0.01),Af组最低(P<0.01)。结论:在不降低冠状动脉成像质量的情况下,等中心扫描联合AIDR3D能降低CCTA的辐射剂量。

Objective:To explore the application value of 320-detector CT isocenter scan combined with AIDR-3D reconstruction in reducing radiation dose of coronary CT angiography(CCTA).Methods:One hundred and eight patients suspected by coronary heart disease were randomly divided into the A,B and C groups(36 cases each group).The coronary CTA scan with a tube voltage of 120 kV in all patients were implemented.The A group were scanned under traditional position,and the tube current was intelligent milliampere.The B and C groups were scanned under isocenter positions(the heart was set at the center of CT rank hole),and the tube currents were 90%and 60%of the intelligent milliampere,respectively.The Af and Aa groups in A group were obtained using the filtering back projection method and AIDR-3D reconstruction,respectively.The B and C groups were reconstructed using AIDR-3D.The signal-to-noise ratio(SNR),contrast-to-noise ratio(CNR),subjective image quality and radiation dose among Af,Aa,B and C groups were compared.Results:The radiation doses in A,B and C groups gradually decreased in turn(P<0.01).The results of the subjective image quality scores in four groups showed that the score in Af group was lower than that in other three groups,and the differences of which among other three groups were not statistically significant(P>0.05).The results of the objective image quality scores in four groups showed that the noise in Af group was the highest(P<0.01),followed by C group(P<0.01),and which in Aa and B groups were the lowest(P<0.01).The SNR and CNR in Aa and B groups were the highest(P<0.01),followed by C group(P<0.01),and whose in Af group were the lowest(P<0.01).Conclusions:The isocenter CT scan combined with AIDR3D can reduce the radiation dose of CCTA without reducing the quality of coronary imaging.