低体质量指数人群门静脉血管成像的低剂量扫描研究

CT Portal Venography with Low Concentration Contrast Agent and Low Tube Voltage Combined with Adaptive Statistical Iterative Reconstruction in Low Body Mass Index Patients

目的探讨低浓度对比剂、低管电压结合自适应统计迭代重组算法(ASIR)用于低体质量指数(BMI)患者门静脉血管成像(CTPV)的可行性。方法搜集拟接受CTPV检查、BMI<22的患者164例,分为双低扫描组(对比剂浓度270 mg I/ml,管电压80 k Vp,加50%ASIR进行图像重组)、常规扫描组(对比剂浓度350 mg I/ml,管电压120 k Vp)。比较两组图像质量评分、门静脉及肝实质CT值、肝实质噪声值(SD值)、门静脉对比噪声比(CNR)、CT剂量指数(CTDIvol)、有效辐射剂量(ED)及总碘含量差异。结果双低扫描组门静脉左支图像质量评分高于常规扫描组(Z=-4.581,P<0.05),门静脉右支图像质量评分两组差异无统计学意义(Z=-0.74,P>0.05);门静脉CT值、肝实质CT值和SD、门静脉CNR双低扫描组均高于常规扫描组(P均<0.01),双低扫描组CTDIvol低于常规扫描组(P<0.01),ED双低扫描组低于常规扫描组,差异无统计学意义(P>0.05)。双低扫描组总碘含量较常规扫描组降低22.86%。结论对低BMI患者行CTPV时采用低浓度对比剂、低管电压结合ASIR可在保证成像质量的同时有效降低辐射剂量和总碘含量,对临床个体化扫描有重要的参考价值。

Objective To investigate the feasibility of CTPV with low concentration contrast and low tube voltage combine with adaptive statistical iterative reconstruction （ASIR） in portal in low body mass index （BMI） patients. Methods Totally 164 patients with BM1 〈 22 were divided into double low scanning group who underwent CTPV with contrast concentration of 270 mgI/ml and tube voltage 80 kVp combined with 50% ASIR, and regular scanning group who underwent CTPV with contrast concentration of 350 mg I/ml and tube voltage 120 kVp. The score of image quality, CT value of the portal veins and the liver, image noise （ SD value） of the liver, CNR of the portal veins, CT dose volume index （ CTDIvol） , effective dose （ED） and the content of iodine were compared between the two groups. Results The image quality score of the left portal venography branches in double low scanning group was significantly higher than that in regular scanning group （Z = -4. 581, P 〈0.05） and there were no difference for the right portal venography branches between the two groups （Z = -0. 74 ,P 〉 0.05 ）. CT value of the portal veins and the liver, SD value of the liver, CNR of the portal veins in double low scanning group were all higher than those in regular scanning group （all P 〈0.01 ）. CTDIvol in double low scanning group was lower than that in regular scanning group （P 〈 0.01 ） , ED was also lower in double low scanning group but with no statistical difference （ P 〉 0.05 ）. The content of iodine in double low group reduced 22.86 %. Conclusion In low BMI patients, CTPV with low concentration contrast and low tube voltage combine with ASIR can effectively reduce the radiation dose without impacting the image quality.