Investigation of MR Imaging With 64 Receiver Channels

描述(由申请人提供)： 该项目的目标是利用一个原型的通道接收系统，开发和表征用于加速速率高达的并行磁共振成像的射频线圈阵列。梯度系统和脉冲序列设计的进步使动态MRI成为一种重要的诊断工具。然而，使用传统的基于梯度的成像速度的进一步提高似乎受到基本问题的限制，包括梯度诱导的周围神经刺激和高射频功率吸收率。在并行成像中，空间定位部分由接收器线圈阵列的接收模式中包含的独特信息来执行，已成为在不增加梯度切换率的情况下减少扫描时间的重要工具。这些方法被称为SMASH、SENSE、SPACE-RIP和其他变体，显示出巨大的前景，但仅被探索到加速系数为8，更典型的是2到3。这部分是由于缺乏具有8个以上接收器通道的磁共振成像系统。 在这个项目中，带有元件的平面和圆柱形阵列线圈将在磁共振系统实验室的4.7T扫描仪上进行设计、制造和测试，扫描仪配备了已经在MRSL建造和测试的通道磁共振接收器原型。阵列将在不同的加速和成像平面上以SNR、伪影功率和分辨率为特征。使用所提出的大阵列的一个重要特征是元素大小在像素的数量级上，并且仅通过平移而彼此不同。正因为如此，阵列单元本身的点扩展函数可能被用来提供增强的或“超分辨率”。将研究在天文成像和合成孔径雷达等领域中使用的超分辨率技术是否有潜力提供更高的空间分辨率，以及滑动窗口技术以提供更高的帧速率(最高可达每个回波一幅图像)的空间分辨率。无论在空间上还是在时间上，都有可能提供更高的分辨率。将研究包括滑动窗口技术在内的其他分辨率增强技术的使用，以便在阵列平面附近成像。 预计该项目将促进我们对高帧速率并行磁共振成像的理解，并为这一新兴领域的研究人员提供数据，以测试具有比以前更多的通道的并行成像算法。

DESCRIPTION (provided by applicant): The objective of this project is to develop and characterize RF coil arrays for parallel MR Imaging at acceleration rates of up to 64 using a prototype 64 channel receiver system. Advances in gradient system and pulse sequence design have made dynamic MRI an important diagnostic tool. However, further increases in speed using conventional gradient based imaging appears limited by fundamental problems including gradient induced peripheral nerve stimulation and high RF power absorbtion rates. Parallel imaging, in which spatial localization is performed partially by the unique information contained in the reception patterns of an array of receiver coils, has become an important tool to reduce scan times without increasing gradient switching rates. These methods, known as SMASH, SENSE, SPACE-RIP and other variations, show great promise, but have only been explored to acceleration factors of 8, and 2 to 3 is more typical. This is partially due to the lack of availability of MRI systems with more than 8 receiver channels. In this project, planar and cylindrical array coils with 64 elements will be designed, fabricated and tested at the Magnetic Resonance Systems Lab on a 4.7 T scanner equipped with a 64 channel MRI receiver prototype that has been built and tested in the MRSL. Arrays will be characterized for SNR, artifact power and resolution at different levels of acceleration and imaging planes. An important feature of using the proposed large arrays is that the element size is on the order of the pixel, and differ from one another only by translation. Because of this, the point spread function of the array element itself can potentially be used to provide enhanced, or "superresolution". Superresolution techniques used in areas such as astronomical imaging and synthetic aperture radar will be investigated for their potential to provide improved spatial resolution, and sliding window techniques to provide improved spatial resolution with frame rates as high as one image per echo. both spatially and temporally, have the potential to provide improved resolution. The use of other resolution enhancement techniques including sliding window techniques will be investigated for imaging close to the array plane. It is expected that this project will advance our understanding of parallel MR imaging at very high frame rates, and provide researchers in this emerging field with data to test parallel imaging algorithms with more channels than previously available.