快速与标准三维时间飞跃法MRA在颅内动脉成像的对比研究

目的评价快速三维时间飞跃法(3D fast time of flight，3D Fast-TOF)磁共振血管成像(magnetic resonance angiography，MRA)在颅内动脉成像中的临床应用价值。材料与方法对34例临床怀疑脑血管病变的患者同时进行标准3D TOF MRA和3D Fast-TOF MRA序列进行脑部动脉成像，其中，2例不能同时顺利完成3D Fast-TOF MRA和标准3D TOF MRA扫描，1例由于运动伪影、图像质量较差，未纳入统计。共31例检查者(男15例，女16例)顺利完成扫描，采用MIP进行三维重建。分别测得原始横断位基底动脉中段和同层脑桥信号并计算图像的信噪比和对比噪声比，对颈内动脉的各级分支显示和图像质量进行评分，对二者的图像质量、血管分支、信噪比(signal to noise ratio，SNR)和对比噪声比(contrast to noise ratio，CNR)进行评分。结果3D Fast-TOF MRA组的颈内动脉分支显示评分为(3.21±0.86)分，标准3D TOF MRA组为(2.51±0.64)分，两组间具有统计学差异(P＜0.01)，3D Fast-TOF MRA组显示血管分支优于标准序列。3D Fast-TOF MRA组图像质量为(4.84±0.58)分，标准3D TOF组图像质量为(4.87±0.56)分，3D Fast-TOF MRA组的SNR、CNR分别为161.17±11.72、124.13±11.28；标准3D TOF组的SNR、CNR分别为149.39±39.91、113.04±29.90；两组间图像质量、SNR、CNR无显著性差异(P＞0.05)，3D Fast-TOF MRA序列扫描时间3.31 min，标准扫描序列扫描时间5.28 min。结论3D Fast-TOF MRA成像技术具有良好的图像质量、较高的空间分辨率，与标准3D TOF序列相比，扫描时间明显缩短，可以作为一种新的磁共振颅内动脉成像技术。

Comparison of three dimensional Fast Time-of-lfight and standard time-of-lfight MR angiography in intracranial arteries

Objective:To investigate the value of 3D Fast-TOF MRA in intracranial arteries.Materials and Methods:3D Fast-TOF and 3D standard TOF sequences were performed in 31 patients. MIP images of intracranial arteries were reconstructed. The image quality (including artifacts), carotid artery branches were compared between the two groups. Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of the source images of both groups were compared.Results:The acquisition time of 3D Fast-TOF group and 3D standard TOF group were 3.31 min and 5.28 min. The image score of carotid artery branches in 3D Fast-TOF group and 3D standard TOF group was 3.21±0.86 and 2.51±0.64 respectively. Signiifcant statistical difference was existed (P<0.01). Demonstration of the carotid artery branches on 3D Fast-TOF group was superior to that of 3D standard TOF group. The image quality scores of the 3D Fast-TOF group and 3D standard TOF group were 4.84±0.58, 4.87±0.56. SNR of 3D Fast-TOF MRA group and 3D Standard TOF group was 161.17, 3D Fast-TOF MRA group; CNR was 124.13±11.28,113.04±29.90. No statistical difference of image quality, SNR and CNR was existed between these tow groups (P>0.05).Conclusion:We demonstrated that 3D Fast-TOF group is a new intracranial MRA technique which could shorten acquisition time, and preserve good imaging quality and high spatial resolution.