Optimization of Catheter Antennas for Intravascular MR

描述(由申请人提供)：本提案旨在优化用于MR引导的血管内介入治疗的导管微射频天线，以实现动脉壁的高分辨率成像。需要大约200微米的分辨率来描绘病变血管壁中的动脉粥样硬化斑块成分。射频天线必须提供高信噪比(SNR)，以在干预期间保持较短的捕获时间(TA)。我们之前的工作表明，简单地改变线圈绕组模式可以使SNR加倍，TA降低4。因此，我们专注于针对导管线圈的信噪比进行深入的优化。为此，将开发一个广泛的计算机模拟程序，该程序将计算作为天线几何形状和相对于BO的方位的函数的3D-SNR图。为了找到适用于特定应用的最佳天线设计，该软件将专门用于：1)对常见的血管内线圈(例如，回路与相对的螺线管线圈)进行正式比较；以及2)通过混合组合多种设计(例如，向相对的螺线管线圈添加回路)，通过改变几何形状来研究可能改善的信噪比。设计更改需要重新计算SNR图。当比较不同的线圈时，将根据在穿过血管和线圈中心的横截面切片中壁面的预期位置计算出的最高SNR来选择最佳设计。我们将把我们的优化限制在冠状动脉和肾动脉成像的线圈上，并通过使用表面贴装或微制造技术的模拟来构建潜在有用的设计。所有组装的设备都将在磁共振体模成像中进行测试。信噪比地图将在多个方向上获取。测量的SNR图将与模拟数据进行比较，并将评估所有制造的线圈的模拟精度。最后，最好的设计将在活体动物模型上进行测试。我们预计，该项目将导致信噪比优化的导管线圈的识别和原型制作，以便在第二阶段在血管疾病动物模型中进一步测试。

DESCRIPTION (provided by applicant): This proposal intends to optimize catheter-based micro radio frequency antennas used in MR-guided, intravascular interventions for high resolution imaging of the arterial wall. A resolution of approximately 200 microns is needed to depict atherosclerotic plaque components in a diseased vessel wall. RF antennas must provide a high signal-to-noise ratio (SNR) to keep acquisition time (TA) short during interventions. Our previous work showed that simple changes in coil winding patterns can double SNR and reduce TA by 4. Thus, we focus on an in-depth optimization of catheter-coils with respect to their SNR. For this purpose, an extensive computer simulation program will be developed which calculates 3D-SNR maps as a function of the antenna geometry and orientation relative to BO. In order to find the best antenna design for a given application, this software will be specifically used to: 1) perform a formal comparison of common intravascular coils (e.g. loop vs. opposed solenoid coil), and 2) investigate possible improvements in SNR by changing geometry through hybrid combination of multiple designs (e.g. by adding loops to an opposed solenoid coil). Design changes necessitate recalculation of the SNR map. When comparing different coils, the best design will be chosen based on the highest SNR calculated at the anticipated location of the wall in a cross-sectional slice through vessel and center of the coil. We will restrict our optimization to coils for coronary and renal artery imaging and construct potentially useful designs identified by simulations using surface mount or micro fabrication technology. All assembled devices will be tested in MR phantom imaging. SNR maps will be acquired at multiple orientations. Measured SNR maps will be compared with simulation data and simulation accuracy for all coils manufactured will be evaluated. Finally, the best designs will be tested in vivo in a porcine animal model. We anticipate that this project will lead to identification and prototyping of SNR-optimized catheter coils for further testing in animal models of vascular disease in Phase II.