颈部CT动静脉同时增强法对影像质量和辐射剂量的影响

Effect of neck CT arteriovenous simultaneous enhancement methods on image quality and radiation dose

目的探讨颈部CT两段式注射对比剂动静脉同时增强扫描的可行性,及其对影像质量和辐射剂量的影响。方法前瞻性纳入2022年2月至4月在首都医科大学附属北京同仁医院因颈部占位性病变行颈部CT增强检查的30例患者为试验组,颈部CT增强采用两段式注射对比剂动静脉同时增强法。对比剂用量按照患者体质量计算,采用两段注射的方法,第一段对比剂用量为0.7 ml/kg,中间注射生理盐水,第35秒注射第二段对比剂,用量为0.3 ml/kg。回顾性收集2021年12月至2022年1月间性别、年龄与试验组匹配的30例患者为对照组,对照组采用传统动脉期和静脉期双期扫描方法,对比剂用量为1.0 ml/kg,第30秒扫描动脉期,第60秒扫描静脉期。测量试验组双侧颈动脉和颈静脉的CT值,测量对照组动脉期双侧颈动脉CT值,测量静脉期双侧颈动脉和颈静脉CT值,并对试验组图像和对照组动脉期、静脉期图像进行颈动脉强化评分,对试验组和对照组静脉期图像进行颈静脉和病变强化评分。计算两组患者的有效剂量。图像间颈动脉CT值差异的比较采用单因素方差分析,两两比较采用LSD法;颈静脉CT值的比较采用独立样本t检验。颈动脉强化评分的比较采用Kruskal-Wallis检验,两两比较采用Nemenyi法;颈静脉和病变强化评分和有效剂量比较采用Mann-Whitney U检验。结果试验组颈动脉CT值[左侧(276±24)HU,右侧(273±25)HU],低于对照组动脉期[左侧(329±33)HU,右侧(327±32)HU],高于对照组静脉期[左侧(147±15)HU,右侧(148±16)HU],差异均有统计学意义(P<0.001)。试验组颈静脉CT值[左侧(206±18)HU,右侧(203±19)HU]高于对照组静脉期[左侧(154±15)HU,右侧(151±15)HU],差异有统计学意义(t=11.88、11.76,P均<0.001)。试验组与对照组动脉期颈动脉强化评分差异无统计学意义(P=0.624),试验组颈动脉强化评分高于对照组静脉期,差异有统计学意义(P<0.001);试验组颈静脉和病变强化评分高于对照组静脉期,差异有统计学意义(Z=5.01,P<0.001)。试验组辐射有效剂量[2.41(2.04,2.72)mSv]较对照组[5.04(4.18,5.44)mSv]下降52.2%,差异有统计学意义(Z=-6.24,P<0.001)。结论两段式注射对比剂动静脉同时增强法进行颈部CT增强扫描可以得到动脉期和静脉期的综合图像,实现颈动脉、颈静脉和病变的同时强化,并降低辐射剂量。

Objective To investigate the feasibility of simultaneous arteriovenous enhancement of neck CT with two-stage injection of contrast agent and its effect on image quality and radiation dose.Methods A total of 30 patients undergoing neck CT enhancement scan due to space-occupying lesions in Beijing Tongren Hospital,Capital Medical University from February to April 2022 were prospectively included as the experimental group.The neck CT enhancement scan was performed with two-stage injection of contrast agent and arteriovenous simultaneous enhancement.The dosage of contrast agent was calculated according to the patient′s body weight,and the method of two-stage injection was adopted.The dosage of contrast agent in the first stage was 0.7 ml/kg,with normal saline in the middle stage,and the second stage(began at 35 s)was 0.3 ml/kg.A total of 30 patients with gender and age matching with the experimental group from December 2021 to January 2022 were retrospectively collected as the control group.The control group was treated with the traditional arterial phase and venous phase scanning method with the dosage of 1.0 ml/kg contrast agent.The arterial phase was scanned at the 30 s and the venous phase was scanned at the 60 s.The CT values of bilateral carotid arteries and jugular veins in the experimental group were measured,the CT values of bilateral carotid arteries in the arterial phase were measured in the control group,and the CT values of bilateral carotid arteries and jugular veins in the venous phase were measured.Carotid artery enhancement score was performed for images of experimental group and control group in arterial and venous phase,and jugular vein and lesion enhancement score was performed for images of experimental group and control group in venous phase.The effective dose was calculated for both groups.The difference of carotid artery CT values between images was compared by one-way analysis of variance,and LSD method was used for pairwise comparison.The CT values of jugular vein were compared using independent sample t test.Kruskal-Wallis test was used to compare carotid artery enhancement scores,and Nemenyi method was used for pairwise comparison.Jugular vein and lesion enhancement scores and effective dose were compared by Mann-Whitney U test.Results The CT value of carotid artery of experimental group[left(276±24)HU,right(273±25)HU]was lower than that of control group in arterial phase[left(329±33)HU,right(327±32)HU],and higher than that in the venous phase[left(147±15)HU,right(148±16)HU].All the differences were statistically significant(P<0.001).The CT value of jugular vein of experimental group[left(206±18)HU,right(203±19)]was higher than that of control group in the venous phase[left(154±15)HU,right(151±15)],the difference was statistically significant(t=11.88,11.76,both P<0.001).There was no significant difference in carotid artery enhancement score between experimental group and control group in arterial phase(P=0.624),but the carotid artery enhancement score of the experimental group was higher than that of the control group in the venous phase,and the difference was statistically significant(P<0.001).The scores of jugular vein and lesion enhancement in experimental group were higher than those of control group in venous phase,and the difference was statistically significant(Z=5.01,P<0.001).The effective dose of the experimental group[2.41(2.04,2.72)mSv]was decreased by 52.2%compared with the control group[5.04(4.18,5.44)mSv],and the difference was statistically significant(Z=-6.24,P<0.001).Conclusions The neck CT enhanced scan with two-stage injection of contrast agent and arteriovenous simultaneous enhancement method can obtain comprehensive images of arterial and venous phases,and realize simultaneous enhancement of carotid artery,jugular vein and lesions,and reduce radiation dose.