自动管电压联合自动管电流在冠状动脉CT血管成像中的应用

Application of Automatic Tube Voltage Combined with Automatic Tube Current Techniques in Coronary CT Angiography

目的探讨自动管电压联合自动管电流在冠状动脉CT血管成像(Coronary Computed Tomography Angiography,CCTA)中的应用价值。方法回顾性收集90例于我院行CCTA的受检者,按照扫描参数分为A组(n=43)和B组(n=47)。A组、B组分别采用固定管电压联合自动管电流(固定管电压100kV,参考管电流370mAs)、自动管电压联合自动管电流(参考管电压100 kV,参考管电流370 mAs)。对比两组的图像质量主观评分、冠状动脉CT值、噪声值、对比噪声比(Contrast to Noise Ratio,CNR)、管电压、管电流、容积CT剂量指数(Volume CT Dose Index,CTDI_(vol))、剂量长度乘积(Dose Length Product,DLP)和有效剂量(Effective Dose,ED)。结果在图像质量方面,两组图像质量主观评分均≤3分,能满足临床诊断要求;两组图像主观评分、CNR差异无统计学意义(P>0.05);B组冠状动脉CT值、噪声值高于A组,差异均有统计学意义(P<0.05)。在辐射剂量方面,B组管电流高于A组,而管电压、CTDI_(vol)、DLP、ED低于A组,差异均有统计学意义(P<0.05);B组的ED较A组明显降低[(1.9±0.7)mSv vs.(2.9±0.9)mSv]。结论自动管电压联合自动管电流在CCTA中可以在保证图像质量的同时,明显降低辐射剂量。

Objective To investigate the application of automatic tube voltage combined with automatic tube current techniques in coronary CT angiography(CCTA).Methods A total of 90 patients who underwent CCTA in our hospital were retrospectively collected and divided into group A(n=43)and group B(n=47)according to scanning parameters.Fixed tube voltage combined with automatic tube current(tube voltage 100 kV,reference tube current 370 mAs)and automatic tube voltage combined with automatic tube current(tube voltage 100 kV,reference tube current 370 mAs)were used in group A and group B,respectively.The subjective score of image quality,coronary attenuation,noise,contrast to noise ratio(CNR),tube voltage,tube current,volume CT dose index(CTDI_(vol)),dose length product(DLP),and effective dose(ED)were compared.Results The subjective scores of image quality of two groups were all≤3 scores,which could meet the requirements of clinical diagnosis.There were no significant differences in subjective score and CNR between two groups(P>0.05).The coronary CT value and noise of group B were higher than those of group A,and the differences were statistically significant(P<0.05).In terms of radiation dose,the tube current of group B was higher than those of group A,while the tube voltage,CTDI_(vol),DLP,and ED of group B were lower than those of group A,the differences were statistically significant(P<0.05).ED of group B was significantly reduced compared with group A[(1.9±0.7)mSv vs.(2.9±0.9)mSv].Conclusion Automatic tube voltage combined with automatic tube current can ensure image quality and at the same time significantly reduce radiation dose in CCTA.