AIDR 3D联合低管电压低对比剂用量在上腹部CT扫描中的应用研究

An application research on AIDR 3D combined with low tube voltage and low contrast agent dose in enhanced CT scan of upper abdomen

目的:探讨三维自适应迭代剂量降低(adaptive iterative dose reduction 3D,AIDR 3D)联合低管电压、低对比剂用量在上腹部CT扫描中的可行性。方法:将60例患者随机分为常规组和低剂量组两组(每组30例)。常规组管电压120 kV,滤波反投影法(filtered back projection,FBP)重建,对比剂用量1.5 mL/kg;低剂量组管电压100 kV,AIDR 3D重建,对比剂用量1.0 mL/kg。测量两组图像肝实质、主动脉、右侧竖脊肌、前腹壁皮下脂肪的CT值及标准差,计算主动脉和肝实质的对比噪声比(contrast-to-noise ratio,CNR)、信噪比(signal-to-noise ratio,SNR),记录容积CT剂量指数(volume CT dose index,CTDIvol)及剂量长度乘积(dose length product,DLP),计算辐射有效辐射剂量(effective dose,ED),并对图像质量进行主观评分。结果:两组图像之间主动脉和肝实质CT值、CNR,SNR,图像噪声差异均无统计学意义(P>0.05);两组图像主观评价差异无统计学意义(P>0.05);低剂量组CTDIvol及ED均低于常规组,差异有统计学意义(P<0.05)。结论:在上腹部CT检查中,AIDR 3D技术联合低管电压(100 kV)、低对比剂用量可在降低辐射剂量和对比剂用量的同时获得满足诊断要求的图像。

Objective:To evaluate the feasibility of adaptive iterative dose reduction 3D (AIDR 3D) combined with low tube voltage andlow contrast agent in CT scan of the upper abdomen.Methods:A total of 60 patients were randomly divided into the conventional group [tube voltage 120 kV, iflter back projection (FBP) reconstruction, contrast agent 1.5 mL/kg] and the low dose group (tube voltage 100 kV, AIDR 3D reconstruction, contrast agent 1.0 mL/kg). Each group had 30 cases. CT values of the liver, aorta, right erector spinae and abdominal subcutaneous fat were measured, and the contrast-to-noise ratio (CNR) of the aortic and liver and signal-to-noise ratio (SNR) were calculated. The volume CT dose index (CTDIvol) and the dose length product (DLP) were recorded, and the effective radiation dose (ED) was calculated. Images were evaluated for rating.Results:The differences in CT values of the aorta and liver, CNR, SNR and image noise between the two groups were not statistically signiifcant (P>0.05). There was no signiifcant difference in subjective score between the two groups (P>0.05). The CTDIvol and ED values in the low dose group were lower than those in the conventional group (P<0.05).Conclusion:AIDR 3D combined with low tube voltage (100 kV) and low contrast agent can not only reduce the radiation dose and contrast agent, but also obtain the images that meet the requirement of diagnosis in CT scan of the upper abdomen.