低剂量对比剂在256层CT头颈血管成像中的应用

Application of Low-dose Contrast Agent in 256-slice CT Angiography for Head-and-neck

目的探讨低剂量(30 ml)对比剂在256层CT头颈部血管成像(CTA)中的可行性,在减少静脉对比剂聚集的同时保证动脉足够强化。资料与方法前瞻性选取头颈部CTA的患者60例,随机分为A、B组。两组扫描参数相同,对比剂注射方案不同。其中A组对比剂总量为60 ml,注射流速为4.0 ml/s,随后以相同速度注射30 ml生理盐水;B组对比剂总量为30 ml,注射流速5.0 ml/s,随后以相同速度注射50 ml生理盐水。分别测量两组图像颈动脉、上腔静脉、头臂静脉、锁骨下静脉及颈静脉的CT值,并对图像质量进行分析。结果 A、B两组上腔静脉、右头臂静脉及右锁骨下静脉CT值比较,差异有统计学意义(P<0.05)。A、B两组左头臂静脉、左锁骨下静脉、左右颈内静脉CT值比较,差异无统计学意义(P>0.05)。A、B两组主动脉弓、左右颈总动脉、左右锁骨下动脉及左右大脑中动脉CT值比较,差异有统计学意义(P<0.05)。A、B两组图像质量评分比较,差异有统计学意义(P<0.05)。结论在头颈部CTA检查中采用30 ml低剂量对比剂图像质量能够满足临床诊断需要,降低了对比剂的用量,并减少上腔静脉、右头臂静脉及右锁骨下静脉的对比剂聚集,减少硬化伪影,同时不影响动脉强化。

Purpose To investigate the feasibility of 30 ml low-dose contrast medium in reducing the accumulation of contrast medium in venous system while maintaining enough artery enhancement in 256-slice CT angiography（CTA） of intracranial and cervical arteries. Materials and Methods Sixty patients with head and neck CTA were recruited prospectively, and they were randomly divided into group A and group B. The scan parameters of the two groups were identical, but the protocol of contrast medium injection was different. Group A was injected 60 ml contrast medium and 30 ml saline successively with the rate of 4.0 ml/s. Group B was injected 30 ml contrast medium and 50 ml saline successively with the rate of 5.0 ml/s. CT attenuation values of aortic arch, common carotid artery, subclavian artery, cerebral middle artery, superior vena cava, innominate vein, subclavian vein, internal jugular vein were measured, and the image quality was evaluated. Results The average CT values of superior vena cava, right innominate vein, right subclavian vein in two groups had significant differences（P〈0.05）. The average CT values of left brachial vein, left subclavian vein, left and right internal jugular vein in two groups had no significant differences（P〉0.05）. The average CT values of aortic arch, left and right common carotid artery, left and right subclavian artery, left and right cerebral middle artery in two groups had significant differences（P〈0.05）. The scores of image quality in two groups also had significant difference（P〈0.05）. Conclusion Head-and-neck CTA with 30 ml low-dose contrast medium is feasible and the images are satisfactory for diagnosis, which can reduce the dose of contrast medium and accumulation of contrast medium in venous system, while maintaining enough artery enhancement.