双源CT小肠造影双能量虚拟平扫与常规平扫对比研究

目的对比研究双源CT小肠造影双能量虚拟平扫与常规平扫图像,探讨虚拟平扫临床应用的可行性。方法采用第三代双源CT对42例患者进行小肠造影检查,行常规CT平扫及动、静脉期对比增强双能量扫描(100 kV和sn150 kV)。利用肝脏VNC软件进行后处理,获得动、静脉期虚拟平扫CT图像。选择基本相同的层面测定常规CT平扫及动、静脉期虚拟平扫正常回肠壁及竖脊肌的CT值和噪声并计算信噪比、对比噪声比;采用5级(0~4分)标准评价三者的图像质量并比较病变检出情况;记录辐射剂量。结果常规平扫和动、静脉期虚拟平扫正常回肠壁及竖脊肌的CT值、SNR、CNR及图像质量评分无统计学差异(P>0.05),虚拟平扫可以显示常规平扫所有病变。常规平扫和动、静脉期增强双能量CT扫描有效辐射剂量分别为(6.23±1.79)、(5.35±1.39)、(5.33±1.37)mSv,常规CT平扫有效辐射剂量高于动、静脉期增强双能量CT扫描(P<0.05),动静脉增强扫描之间差异无统计学意义(P>0.05)。结论双源CT双能量小肠造影虚拟平扫成像有可能代替传统常规平扫,降低患者接受的辐射剂量。

Comparative Study of Virtual and Conventional Non-Contrast CT Enterography Using Dual-Source and Energy CT

Objective To compare dual-energy virtual non-contrast(VNC)and conventional non-contrast CT enterography using dual-source CT,and investigate the clinical feasibility of VNC.Methods 42 patients received the third-generation dual-source CT enterography which included conventional non-contrast CT,arterial and venous phase contrast enhanced dual-energy scan(100 kV and sn150 kV).VNC CT images were reformatted by“Liver VNC”software.The mean CT values,noise of normal ileum wall and erector spinae,signal to noise ratio(SNR)and contrast to noise ratio(CNR)were measured and calculated in the same location.The imaging quality of conventional non-contrast and VNC images were evaluated by 5 grade(0-4 points)standard,and the diagnostic consistency was compared.The radiation doses were recorded.Results There was no significant difference in mean CT value,SNR,CNR and imaging quality between conventional non-contrast and VNC images(P>0.05).Compared with conventional non-contrast CT images,all lesions were also detected by VNC CT images.The effective radiation dose of conventional non-contrast,dynamic and venous phase enhanced dual energy CT scanning were(6.23+1.79),(5.35+1.39),(5.33+1.37)mSv respectively.The effective radiation dose(ED)of conventional non-contrast CT was higher than that of contrast enhanced dual-energy scan in arterial and venous phase(P<0.05),and there was no significant difference between them(P>0.05).Conclusion Dual-source and energy VNC CT enterography requires less radiation dose and has a potential to replace the conventional non-contrast CT.