Department of Electrical Engineering, Stanford University, Stanford, California 94305, USA.
Magn Reson Med. 2013 May;69(5):1268-75. doi: 10.1002/mrm.24356. Epub 2012 Jun 18.
Non-contrast-enhanced MR angiography is a promising alternative to the established contrast-enhanced approach as it reduces patient discomfort and examination costs and avoids the risk of nephrogenic systemic fibrosis. Inflow-sensitive slab-selective inversion recovery imaging has been used with great promise, particularly for abdominal applications, but has limited craniocaudal coverage due to inflow time constraints. In this work, a new non-contrast-enhanced MR angiography method using velocity-selective inversion preparation is developed and applied to renal and abdominal angiography. Based on the excitation k-space formalism and Shinnar-Le-Roux transform, a velocity-selective excitation pulse is designed that inverts stationary tissues and venous blood while preserving inferiorly flowing arterial blood. As the magnetization of the arterial blood in the abdominal aorta and iliac arteries is well preserved during the magnetization preparation, artery visualization over a large abdominal field of view is achievable with an inversion delay time that is chosen for optimal background suppression. Healthy volunteer tests demonstrate that the proposed method significantly increases the extent of visible arteries compared with the slab-selective approach, covering renal arteries through iliac arteries over a craniocaudal field of view of 340 mm.
非对比增强磁共振血管成像作为一种有前途的替代方法，与已建立的对比增强方法相比，它减少了患者的不适和检查成本，并避免了肾源性系统性纤维化的风险。流入敏感的切片选择性反转恢复成像是一种非常有前途的技术，特别是在腹部应用中，但由于流入时间的限制，其颅尾覆盖范围有限。在这项工作中，开发了一种新的使用速度选择反转准备的非对比增强磁共振血管成像方法，并将其应用于肾和腹部血管造影。基于激励 k 空间公式和 Shinnar-Le-Roux 变换，设计了一种速度选择激励脉冲，该脉冲反转静止组织和静脉血，同时保留向下流动的动脉血。由于腹部主动脉和髂动脉中的动脉血的磁化在磁化准备期间得到很好的保持，因此可以选择最佳的背景抑制反转延迟时间，实现大腹部视野内的动脉可视化。健康志愿者测试表明，与切片选择性方法相比，该方法显著增加了可见动脉的范围，覆盖了从肾动脉到髂动脉的整个颅尾视野，范围为 340 毫米。
