摘要
目的探讨多层螺旋 CT 颅颈联合动脉成像追踪触发技术的应用,以及准直与螺距的最佳匹配方案。方法 (1)19名志愿者进行同层动态增强扫描,以时间密度曲线峰值之前4 s 处对应CT 值的平均值作为触发技术的理论阈值。(2)40名志愿者按随机数字表随机分为 A 组(准直1.0mm,螺距1.750)和 B 组(准直2.5 mm,螺距0.625),评价三维血管质量,探讨准直与螺距的恰当匹配。统计方法采用成组设计的两样本均数 t 检验(双侧,α=0.05)。结果 (1)19例时间密度曲线峰值之前4 s处对应 CT 值的平均值为75 HU。(2)按照三维动脉质量评分标准,B 组对颈总动脉、颈内动脉、大脑中动脉、额顶升动脉、终末支的评分分别为(2.85±0.37)、(2.64±0.49)、(2.29±0.72)、(1.70±0.98)、(1.07±0.94)分,A 组分别为(2.40±0.50)、(2.31±0.47)、(2.70±0.57)、(2.35±0.75)、(1.96±0.89);B 组对颈总动脉和颈内动脉等大动脉的成像质量较佳,血管边缘光滑、锐利,A 组对大脑中动脉、额顶升动脉及终末支动脉等小动脉的细节显示清晰。A、B 两组间的三维动脉质量差异有统计学意义(P 值均<0.05)。结论 (1)追踪触发技术可更好地显示头颈部血管。对比剂注射流率3.5 ml/s 时,触发阈值为75 HU 的图像质量较佳。(2)颅颈联合 CT 血管造影采用准直1.0mm、螺距1.750优于准直2.5 mm、螺距0.625,这种匹配方式对小血管显示较佳。
Objective To explore application of the bolus-triggered technique and optimal match between collimation and pitch of MSCTA in intracranial and cervical arteries. Methods （ 1 ） The small-dose tests were performed in 19 healthy volunteers and the theoretical threshold was obtained by the time-density curve. （2） forty healthy volunteers were divided randomly into two groups and the scanning parameters were as follows. Group A： collimation 1.0 mm, pitch 1.750, Group B： collimation 2.5 mm, pitch 0.625, Statistical significance was determined with the χ^2 test and t test （α = 0. 05 ） . Results （ 1 ） In 19 volunteers, CT value 4 seconds before the peak was 75 HU, the CT value at the beginning segment of the carotid artery and the C1 segment of internal carotid artery was in accordance with the standard. （2） Image quality of Ⅰ, Ⅱ grades artery structures of group B was superior to that of group A. Image quality of Ⅲ, Ⅴ grades artery structures of group A was superior to that of group B. Conclusions （ 1 ） MSCTA in intracranial and cervical arteries can display systematically the cerebral and carotid arteries. （ 2 ） The bolus-triggered technique can improve the image quality of the target vessels. The image quality of the MSCTA of intracranial and cervical arteries is better with the threshold of 75 HU on the basis of 3. 5 ml/s injection rate. （3） On the basis of the same other parameters, the optimal scanning parameters are a collimation of 1.0 mm with a pitch of 1. 750.
出处
《中华放射学杂志》
CAS
CSCD
北大核心
2006年第9期970-973,共4页
Chinese Journal of Radiology
