Wang Hui, Kadbi Mo, Kotys Melanie, Ersoy Mehmet, Chatzimavroudis George P, Setser Randolph M, Alshaher Motaz, Fischer Stefan E, Amini Amir A
Department of Electrical and Computer Engineering, University of Louisville, Louisville, KY 40292, USA.
Annu Int Conf IEEE Eng Med Biol Soc. 2011;2011:535-8. doi: 10.1109/IEMBS.2011.6090098.
Tagged magnetic resonance imaging (MRI) has the ability to directly and non-invasively alter tissue magnetization and produce tags on the deforming tissue [1], [2]. Since its development, the Spatial Modulation of Magnetization (SPAMM) [2] tagging pulse sequence has been widely available and is the most commonly used technique for producing sinusoidal tag patterns. However, SPAMM suffers from tag fading which occurs in the later phases of the cardiac cycle. Complementary SPAMM (CSPAMM) was introduced to solve this problem by acquiring and subtracting two SPAMM images [3]. The drawback of CSPAMM is that it results in doubling of the acquisition time. In this paper, we propose a novel pulse sequence, termed Orthogonal CSPAMM (OCSAPMM), which results in the same acquisition time as SPAMM for 2D deformation estimation while keeping the advantages of CSPAMM. Different from CSPAMM, in OCSPAMM the second tagging pulse orientation is rotated 90 degrees relative to the first one so that motion information can be obtained simultaneously in two directions. A cardiac motion phantom, which independently models cardiac wall thickening and rotation in the human heart was used to show the effectiveness of the proposed pulse sequence.
标记磁共振成像（MRI）能够直接且无创地改变组织磁化，并在变形组织上产生标记[1,2]。自其发展以来，磁化空间调制（SPAMM）[2]标记脉冲序列已广泛可用，并且是产生正弦标记图案最常用的技术。然而，SPAMM存在标记衰减问题，该问题出现在心动周期的后期阶段。互补SPAMM（CSPAMM）被引入以通过采集和相减两幅SPAMM图像来解决此问题[3]。CSPAMM的缺点是它会使采集时间加倍。在本文中，我们提出了一种新颖的脉冲序列，称为正交CSPAMM（OCSPAMM），对于二维变形估计，它与SPAMM具有相同的采集时间，同时保留了CSPAMM的优点。与CSPAMM不同，在OCSPAMM中，第二个标记脉冲方向相对于第一个旋转90度，以便可以在两个方向上同时获得运动信息。使用一个独立模拟人体心脏心肌增厚和旋转的心脏运动模型来展示所提出脉冲序列的有效性。
