NOVEL ENCODING TECHNOLOGY FOR MRI

该提案的目标是探索一种全新的MRI空间编码领域。 该字段称为PERL，在x维中为周期性，在y维中为线性。 它是唯一的，因为它是两个正交空间变量的函数，并且是空间周期性的。 重建也是唯一的，涉及在一个维度上的傅里叶变换和贝塞尔函数积分变换的解决方案在其他。理论分析表明，PERL为MRI提供了几种令人兴奋的可能性。 例如，PERL MRI的空间分辨率可以在成像时间或SNR方面没有成本的情况下增加，因此可以很好地适合于高分辨率肿瘤成像。 此外，PERL重建的基函数是空间局部化的，因此PERL可以是手术引导的理想候选者，其中仅视场的一部分发生变化。 此外，场的周期性性质使得能够实现优雅的流量测量技术，即，移动相阵面，从而允许相对于移动参考系的速度相关测量。 理论还表明，连续的PERL自旋回波彼此异相90 °，这意味着数据采集可以比传统方法增加两倍。 此外，PERL分析提供了一种通过提供包括这些传统线圈的非线性区域的机制来增强使用标准“线性”梯度线圈的传统MRI中的FOV的方式。 PERL线圈自然地在扁平线圈形式上实现，并且因此可以紧邻身体定位，从而作为高效表面“梯度”线圈操作。PERL线圈也是理想的，因为它具有零洛伦兹力，最小的涡电流和非常低的电感。 在研究中，我们将设计和构建PERL线圈，包括集成RF线圈，并通过实验实现PERL MRI。将进行基本实验和数值模拟来测试PERL的上述独特功能，以了解其相对于潜在临床应用的真实的优势和劣势。

This proposal's goal is to explore a radically new spatial encoding field for MRI. The field, called PERL, is PERiodic in the x-dimension and Linear in the y-dimension. It is unique because it is a function of two orthogonal spatial variables and is spatially periodic. The reconstruction is also unique, involving a Fourier transform in one dimension and the solution of a Bessel function integral transform in the other. Theoretical analysis shows that PERL offers several exciting possibilities for MRI. For example, the spatial resolution for PERL MRI can be increased with no cost in either imaging time or SNR and thus may be well suited for high-resolution tumor imaging. Further, the basis functions for the PERL reconstruction are spatially localized and thus PERL may be an ideal candidate for surgical guidance where only a portion of the field of view is changing. In addition, the periodic nature of the field enables an elegant flow measurement technique, i.e. a moving phase front, allowing velocity dependent measurements relative to a moving reference frame. Theory also shows that successive PERL spin echoes are 90 out of phase with each other, implying that data acquisition may be increased by a factor of two over traditional methods. Furthermore, the PERL analysis provides a way to enhance the FOV in traditional MRI that uses standard "linear" gradient coils by providing a mechanism to include nonlinear regions of these traditional coils. A PERL coil is naturally implemented on a flat coil form and can thus be positioned immediately adjacent to the body, thereby operating as a high efficiency surface "gradient" coil. The PERL coil is also desirable in that it has zero Lorentz force, minimal eddy currents and very low inductance. In the research proposed, we will design and build PERL coils, including an integrated RF coil, and experimentally implement PERL MRI. Basic experiments and numerical simulations will be performed to test the above-mentioned unique features of PERL to obtain an understanding of where its real strengths and weaknesses lie relative to potential clinical applications.