Stehning C, Börnert P, Nehrke K, Dössel O
Institute of Biomedical Engineering, Kaiserstrasse 12, D-76128 Karlsruhe, Germany.
Magn Reson Med. 2005 Mar;53(3):719-23. doi: 10.1002/mrm.20397.
A shortcoming of today's coronary magnetic resonance angiography (MRA) is its low total scan efficiency (<5%), as only small well-defined fractions of the respiratory (50%) and cardiac (10%) cycle are used for data acquisition. These precautions are necessary to prevent blurring and artifacts related to respiratory and cardiac motion. Hence, scan times range from 4 to 9 min, which may not be tolerated by patients. To overcome this drawback, an ECG-triggered, navigator-gated free breathing radial 3D balanced FFE sequence with intra-RR motion correction is investigated in this study. Scan efficiency is increased by using a long cardiac acquisition window during the RR interval. This allows the acquisition of a number of independent k-space segments during each cardiac cycle. The intersegment motion is corrected using a self-guided epicardial fat tracking procedure in a postprocessing step. Finally, combining the motion-corrected segments forms a high-resolution image. Experiments on healthy volunteers are presented to show the basic feasibility of this approach.
当今冠状动脉磁共振血管造影（MRA）的一个缺点是其总扫描效率较低（<5%），因为仅使用呼吸周期（50%）和心动周期（10%）中定义明确的小部分来进行数据采集。这些预防措施对于防止与呼吸和心脏运动相关的模糊和伪影是必要的。因此，扫描时间为4至9分钟，这可能是患者无法耐受的。为了克服这一缺点，本研究对一种具有RR间期内运动校正的心电图触发、导航门控自由呼吸径向三维平衡快速场回波序列进行了研究。通过在RR间期使用较长的心电采集窗来提高扫描效率。这使得在每个心动周期内能够采集多个独立的k空间段。在后期处理步骤中，使用自引导的心外膜脂肪追踪程序校正段间运动。最后，将经运动校正的段组合形成高分辨率图像。本文展示了在健康志愿者身上进行的实验，以证明该方法的基本可行性。
