磁共振脑血管造影MOTSA法成像参数评估

Evaluation of Multiple Overlapping Thin Slab Acquisition (MOTSA) MRA Parameters in the Intracranial Vascular

目的：评价磁共振脑血管造影ＭＯＴＳＡ法成像参数对脑血管结构的显示能力。材料与方法：对１８０例（男１２４例，女５６例，年龄４～７２岁，平均４８岁）患者和怀疑脑血管病的患者用ＧＥＳｉｇｎａ１．５Ｔ磁共振仪进行ＭＯＴＳＡＭＲＡ检查，运用不同的技术参数，所得原始图像用ＭＩＰ处理。分析血管结构的显示与技术参数的关系。结果：磁化转移技术有效的抑制脑组织信号，增强血管的显示能力，使机器所允许的最短ＴＲ增加约１５ｍｓ，延长了扫描时间，可变翻转角射频脉冲（ｒａｍｐｐｕｌｓｅ）技术明显影响了层块（ｓｌａｂ）连接的完整性；当ＴＥ＝６．９ｍｓ，最大程度抑制了脂肪信号，明显降低了背景组织的信号；高分辨率５１２矩阵，减小脑组织的信号，小血管的片段显示能力得以改善。结论：合理准确运用ＭＯＴＳＡＭＲＡ成像的技术参数，能改善血管的显示能力，提高ＭＲＡ的敏感性。

Objective: Assess the ability of MOTSA MRA parameters in demonstrating cerebral vascular structure.Materials and Methods: MOTSA MRA of the intracranial vasculature with different parameters was performed in 180 patients (124 men and 56 women, aged from 4～72 years, mean ages 48 years) with known or suspected cerebravascular disease. MR scanner is GE Signa 1.5T. MR angiograms were reconstructed with maximum intensity projection. The ability to depict the cerebral vascular structure with various MRA parameters was analysed.Results: Magnetization transfer (MT) pulse reduced the signal of the background stationary tissue and improved the depiction of intracranial vessels while examination time is lengthened due to increasment TR to 15ms. Changeable ramp pulse effected markedly the intact connection of slab, when TE=6.9ms , the fat signal was inhibited in greatbest degree, and reduced the signal of background tissue. The ability to depict segment of small vessels was improved by 512 high resolution matrix. Conclusion: The depiction of intracranial vessels and sensitivity of MRA was improved through the appropriate selection of MOSTA MRA acquisition parameters.