双通道联合注射法在下肢CT血管造影、CT静脉造影同时成像中的应用价值

Study on the Application Value of Dual-Channel Combined Injection in the Simultaneous Imaging of Lower Limb CT Angiography and CT Venography

目的探讨经肘、足背静脉联合注射对比剂行下肢CT血管造影(CTA)、CT静脉造影(CTV)同时成像的应用价值。方法将临床怀疑有下肢血管性疾病或下肢肿瘤性疾病需要行下肢血管CT的60例患者纳入研究,60例患者随机分为对照组(A组)和实验组(B组)各30例,A组采用经肘静脉注射适量对比剂先行双侧下肢CTA,经过180 s后再行单侧下肢间接法CTV;B组采用经肘静脉注射适量对比剂和经足背静脉注射适量稀释对比剂混合液的联合注射方法,一次扫描完成双侧下肢CTA、单侧CTV同时成像。将A、B两组图像进行多平面重组(MPR)、最大密度投影(MIP)、容积再现(VR)图像后处理重组,由两名放射科医师以节段为单位分别对动脉和静脉血管图像质量进行主观评分,以节段为单位测量两组图像的CT值,并计算信噪比(SNR)和对比噪声比(CNR)。比较两组图像主观评分和客观质量评价(CT值、SNR、CNR)的差异性,比较两组患者CT剂量长度乘积(DLP)的差异性。结果A、B两组动脉血管各节段主观评分和客观质量评价均无显著性差异(P均>0.05);静脉血管各节段主观评分和客观质量评价,B组均显著高于A组(P均<0.05);B组DLP低于A组(P<0.05)。结论双通道联合注射法行下肢CTA、CTV同时成像,图像质量高,辐射剂量小,可实现CTA和CTV在下肢血管中的同时高质量成像,值得推广。

Objective To explore the value of simultaneous CT angiography(CTA)and CT venography(CTV)of lower limbs by injection of contrast agent through elbow vein and foot dorsal vein.Methods 60 patients who were clinically suspected to have vascular diseases or tumor diseases of lower extremity and needed the lower extremity CT angiography were included in this study.The 60 patients were randomly divided into the control group A and the experimental group B,with 30 cases in each group.In group A,a bilateral lower extremity CTA imaging was performed by injecting appropriate amount of contrast agent through elbow vein firstly,and then a unilateral lower extremity indirect CTV imaging was performed after 180 seconds;In group B,the combined injection method of appropriate amount of contrast agent injected through elbow vein and appropriate amount of diluted contrast agent mixed solution injected through foot dorsal vein was adopted,CTA and unilateral CTV of both lower limbs were simultaneously imaged in one scan.Images of A,B groups were reconstructed by MPR,MIP and VR image post processing reconstruction,and two radiologists rated the image quality subjectively in arterial and venous vessels.The CT values of the two groups of images were measured in segments,and the signal to noise ratio(SNR)and the contrast to noise ratio(CNR)were calculated.The differences of the subjective scores and the objective quality evaluations(CT value,SNR and CNR)between the two groups were compared,and the difference of CT dose length product(DLP)between the two groups was compared.Results There was no significant difference between the subjective scores and the objective quality evaluations of each segment of the artery between group A and B(P>0.05);the subjective scores and objective quality evaluations of each segment of the vein were higher in group B than those in group A(P<0.05);DLP in group B was lower than that in group A(P<0.05).Conclusion The dual channel combined injection method of CTA and CTV for simultaneous imaging of lower limbs has high image quality and low radiation dose.It can realize simultaneous high quality imaging of CTA and CTV in lower limb vessels and is worthy of promotion.