Biomedical Engineering, Northwestern University, Chicago, Illinois, USA.
Magn Reson Med. 2010 Jun;63(6):1520-8. doi: 10.1002/mrm.22373.
A new four-dimensional magnetic resonance angiography (MRA) technique called contrast-enhanced angiography with multiecho and radial k-space is introduced, which accelerates the acquisition using multiecho while maintaining a high spatial resolution and increasing the signal-to-noise ratio (SNR). An acceleration factor of approximately 2 is achieved without parallel imaging or undersampling by multiecho (i.e., echo-planar imaging) acquisition. SNR is gained from (1) longer pulse repetition times, which allow more time for T(1) regrowth; (2) decreased specific absorption rate, which allows use of flip angles that maximize contrast at high field; and (3) minimized effects of a transient contrast bolus signal with a shorter temporal footprint. Simulations, phantom studies, and in vivo scans were performed. Contrast-enhanced angiography with multiecho and radial k-space can be combined with parallel imaging techniques such as Generalized Autocalibrating Partially Parallel Acquisitions (GRAPPA) to provide additional 2-fold acceleration in addition to higher SNR to trade off for parallel imaging. This technique can be useful in diagnosing vascular lesions where accurate dynamic information is necessary.
介绍一种新的四维磁共振血管造影（MRA）技术，称为对比增强血管造影多回波和径向 k 空间，它使用多回波加速采集，同时保持高空间分辨率并提高信噪比（SNR）。通过多回波（即：回波平面成像）采集，在不使用并行成像或欠采样的情况下实现约 2 倍的加速因子。SNR 来自于：（1）更长的脉冲重复时间，允许更多的 T1 再生长时间；（2）降低的特定吸收率，允许在高场下使用最大化对比度的翻转角；（3）通过缩短瞬态对比团注信号的时间足迹来最小化其影响。进行了模拟、体模研究和体内扫描。对比增强血管造影多回波和径向 k 空间可以与并行成像技术（如广义自动校准部分并行采集（GRAPPA））相结合，除了更高的 SNR 之外，还提供额外的 2 倍加速，以平衡并行成像。该技术在诊断需要准确动态信息的血管病变时非常有用。
