低管电压联合低浓度对比剂对下肢动脉CT血管成像质量与辐射剂量的研究

Effect of Low Tube Voltage Combined with Low Concentration Contrast Agent on the Image Quality and Radiation Dose of Lower Extremity CT Angiography

目的探讨低管电压联合低浓度对比剂对下肢动脉CT血管成像(CTA)图像质量、辐射剂量和碘摄入量的影响。方法连续收集2015年1月至2016年12月四川省肿瘤医院因股前外侧穿支皮瓣(ALTPF)移植术前评估需要拟行下肢动脉CTA检查的32例患者,按随机数字表法分为试验组和对照组,每组各16例。试验组的管电压、对比剂浓度和重建算法分别为100kV、含碘300mg/mL、iDose4迭代算法;对照组分别为120kV、含碘370mg/mL、滤波反投影法。对图像质量进行主观评分和客观评价,记录有效剂量(E)、碘摄入量和穿支动脉吻合率。两组间客观评价指标、E和碘摄入量的比较采用t检验,主观评分比较采用Mann-whitney U检验,穿支动脉吻合率的比较采用X^2检验。结果试验组和对照组图像质量均满足ALTPF移植术前评估要求,两组间主观评分比较,差异无统计学意义(P>0.05)。两组间旋股外侧动脉降支信噪比(SNR)比较,差异无统计学意义(P>0.05)。两组间穿支动脉吻合率比较,差异无统计学意义(P>0.05)。试验组的E和碘摄入量低于对照组,差异有统计学意义(P<0.05)。结论采用低管电压联合低浓度对比剂行下肢动脉CTA可保证图像质量,满足ALTPF移植术前评估要求,且能有效降低辐射剂量和碘摄入量。

Objective To explore the effect of low tube voltage combined with low concentration contrast agent on the image quality,radiation dose and iodine intake of lower extremity CT angiography(CTA).Methods Thirty-two patients undergoing lower extremity CAT for preoperative assessment of anterolateral thigh perforator flap(ALTPF)transplantation in Sichuan Cancer Hospital from January of 2015 to December of 2016 were selected consecutively and randomized into the test group and control group,and each group included 16 cases.The test group was given the tube voltage of 100kV,iodine of 300mg/ml,and iterative algorithm of iDose4,while the control group received the tube voltage of 120kV,iodine of 370mg/ml,and filtered-back projection.The image quality was scored subjectively and evaluated objectively,and the effective dose,iodine intake and anastomosis rate of perforating artery were also recorded.The t test analysis was performed to compare the objective evaluation index,effective dose and iodine intake between two groups,the Mann-whitney U test analysis was made to compare the subjective scores,and theχ2 test analysis was conducted to compare the anastomosis rate of perforating artery.Results The image quality of both groups met the preoperative evaluation requirement of ALTPF transplantation,and there was no significant difference in the subjective scoring between the two groups(P>0.05).There were no significant differences in anastomosis rate of perforating artery and SNR of the descending branch of lateral circumflex femoral artery respectively between the two groups(P>0.05).The effective dose and iodine intake in the test group were significantly lower than those in the control group(P<0.05).Conclusion The low tube voltage combined with low concentration contrast agent in lower extremity CTA can ensure that the image quality meets the preoperative assessment requirement of ALTPF transplantation and it can also effectively reduce the radiation dose and iodine intake.