不同体位对双上肢CTA图像质量的影响

The Effect of Different Position on The Image Quality of Upper Extremity CT Angiography

目的探讨CT血管造影(CTA)在观察透析患者动静脉内瘘中的作用,以及成像过程中双上肢上举或自然下垂于腹部两种不同体位对图像质量的影响。方法回顾性分析20例上肢动静脉内瘘患者的CTA图像,10例在检查时双上肢上举,10例自然下垂置于腹部。在内瘘的动脉流入、动静脉吻合口、前臂和上臂静脉流出以及中心静脉分别设置感兴趣区(ROI),测量ROI的信噪比(SNR)和对比噪声比(CNR),评价图像质量。结果在流入动脉及动静脉瘘口处,不同体位下两组的SNR及CNR存在显著性差异。结论不同体位下两组图像均可用于临床诊断。如在患者可耐受范围内,推荐采用双上肢上举体位进行CTA检查,对流入动脉及动静脉瘘口显示更好。

Objective The purpose of our study was to discuss the utilization of CTA to evaluation hemodialysis arteriovenousfistulas(AVFs), and compare the effect of arm position on image quality. Methods Our study retrospectively analyzed the data of 20 patients with hemodialysis fistula who underwent MDCT angiography with arms raised above the shoulder region(n=10) or both arms were down(n=10).The regions of interests(ROIs) were set on distal arterial inflow, arteriovenous anastomosis, forearm, distal half of upper arm, proximal half of upper arm, and central veins. Subjective image quality was assessed with two parameters: signal-to-noise ratio and contrast to noise ratio. Results The arm raised group displayed better image quality on distal arterial inflow,arteriovenous anastomosis regions than both arms down group(P<0.05). Conclusion We recommended arms raised up as the first choice position when a patient with hemodialysis fistula underwent a upper extremity CTA examination.