Department of Radiology, Wayne State University, Detroit, Michigan, USA.
J Magn Reson Imaging. 2013 Dec;38(6):1539-48. doi: 10.1002/jmri.24128. Epub 2013 Apr 4.
To achieve simultaneous high-resolution magnetic resonance angiography and venography (MRAV) imaging in terms of enhanced time-of-flight (TOF) angiography and susceptibility-weighted imaging (SWI), with a clear separation of arteries and veins.
A new flow rephase/dephase interleaved double-echo sequence was introduced that facilitates multiple types of imaging contrast, i.e., TOF, SWI, and dark blood, in a single acquisition. A nonlinear subtraction (NLS) method is proposed and assessed to maximally enhance angiography contrast with minimum venous contamination.
Fully flow rephased TOF MRA and SWI MRV data were acquired simultaneously, along with an extra flow dephased dark blood image for angiography enhancement calculation. Compared to linear subtraction methods, the proposed NLS method was able to enhance angiography contrast while effectively eliminating vein-tissue contrast. The NLS method even outperformed low-dose contrast-enhanced MRA for a clean, enhanced angiography map.
Using the proposed interleaved double-echo sequence along with the NLS postprocessing method, one can simultaneously obtain both high-quality SWI and significantly enhanced TOF MRA with clear separation of arterial and venous maps.
实现基于增强时间飞跃（TOF）血管造影和磁化率加权成像（SWI）的同时高分辨率磁共振血管造影和静脉造影（MRAV）成像，清晰分离动脉和静脉。
引入了一种新的流重相位/去相位交错双回波序列，可在单次采集中实现多种成像对比，即 TOF、SWI 和黑血。提出并评估了一种非线性减影（NLS）方法，以最大程度地增强血管造影对比度，同时最小化静脉污染。
同时获得了完全流重相位 TOF MRA 和 SWI MRV 数据，以及用于血管造影增强计算的额外的流去相位黑血图像。与线性减影方法相比，所提出的 NLS 方法能够增强血管造影对比度，同时有效消除静脉-组织对比度。NLS 方法甚至优于低剂量对比增强 MRA，可获得干净、增强的血管造影图。
使用所提出的交错双回波序列和 NLS 后处理方法，可以同时获得高质量的 SWI 和明显增强的 TOF MRA，清晰分离动脉和静脉图。
