多个薄层扫描块重叠采集与移行饱和组合技术在颅外段脑动脉磁共振血流成像中的应用研究

目的：采用多个薄层扫描块重迭采集（MOTSA）与移行饱和组合序列（TSC）对颈部动脉行MRA前瞻性研究，选择颅外段脑动脉MRA的优化序列组合。材料与方法：正常人组40例，疾病组4例。均同时行MOTSA、TSCMRA。疾病组1例同时行DSA。结果：MOTSA技术MRA空间分辨率高。血管、背景对比好，病变显示清晰，但检查时间长，块间连接较繁琐；TSC血流信号强度高，块间连续简便，无明显饱和伪影，缺点是对涡流敏感，血管迂曲处信号丢失。结论：以2DTSC观察血管全长，3DTOF－TONE观察血管局部是颅外段脑动脉TOF法MRA较好的序列组合。

Prospective Evaluation of Extracranial Cerebral Artery: Correlation between MR Angiography with MOTSA and MR Angiography with TSC

PURPOSE To campare multiple overlapping thin slab acquisition(MOTSA)with travelling sat combine(TSC) in MR angiography of the extracranial cerebral artery. MATERIALS AND METHODS The extracranial arteries in forty volunteers and four cases with occlusive disease of cerebral artery were studied with MOTSA MRA and TSC MRA prospectively.MOTSA studies were performed using 3D TOF TONE axial aquisition.Four slabs were acquired sequentially with twenty slices(1mm thick)overlap.TSC technique with two sequences was acquired combined together with an MIP algorithm.Preseturation regions were positioned just above each successive slice,travelling inferiorly as the slice position moved caudally. RESULTS MOTSA was better resolution and less sensitive to turbulence than was TSC technique.MOTSA provided better delineation of vassel margin of the extracranial artery but aquired scan times were longer and differences in saturation between different slabs led to saturation artifact.TSC provided maximal flow related enhancement and gave the entire course of extracranial cerebral artery easier than MOTSA.Problems with TSC included thicker slices,decreased spatical resolution,and increased sensitivity to turbulence (in plane saturation). CONCLUSION 2D TOF TSC is an ideal technique for the entire course of the extracranial cerebal artery.3D TOF TONE is of benefit to defined region of interest.