Modified Elliptical Centric View Orders for Improved Real-Time MRA

描述（由申请人提供）：本资助申请的总体目的是进一步利用在上一个资助周期中在对比增强磁共振血管造影（CE-MRA）方面取得的广泛进展，并将该领域推向更高的水平。在过去的几年里，CE-MRA取得了多项发展，我们相信我们自己小组的工作对此做出了重大贡献。具体的发展包括：(i)当二维并行采集应用于椭圆中心CE-MRA时，信号增强效果的演示；（ii）在加速CE-MRA中改善血管清晰度的演示；（iii）开发了用于时间分辨CE-MRA的带有类似投影重建采样（CAPR）脉冲序列的笛卡尔采集；（iv） CE-MRA中加速因子超过10的常规演示；(v)开发用于加速CE-MRA的模块化线圈阵列；(v)证明CAPR对动态现象的描述具有高保真度；（vi）常规展示高质量的时间分辨率三维CE-MR脑和小腿血管造影。具体研究目标有：1、研究目标：高质量神经血管综合检查。作为20- 23年工作的延伸，我们将在一次综合检查中生成主动脉弓、颈动脉、颅内动脉和脑引流静脉的高质量图像。用于评估2D切片时间的传统测试丸将被低剂量（1- 2ml） 3D时间分辨CE-MRA序列所取代。随后将进行正常剂量（18毫升）采集，其中多元素模块化RF线圈阵列将允许2D加速采集，为所有地区提供高空间分辨率数据集。上肢和腹部的高分辨率CAPR。以前为脑和小腿的磁共振血管造影开发的平行采集技术将适用于其他解剖区域。对于每个区域，模块化线圈阵列元素将匹配到特定的视场（FOV）和所需的空间分辨率。对于手来说，FOV通常是不对称的（L/R vs. A/P），这表明对于小腿来说，元素的大小是不同的。对于腹部，增加的FOV需要更大的线圈元素。3. 联合血管造影和灌注磁共振成像。对CAPR CE-MRA脑实质信号水平的分析表明，首过脑实质“脸红”是可检测到的，这表明从血管造影数据集提供灌注信息的潜力。然而，这可能会受到帧时间的限制，帧时间仍然有点长，信噪比也有点小。为了解决这个问题，我们将使用10倍或更高的2D SENSE加速因子来调整基本CAPR序列以提高时间分辨率。为了保持信噪比，特别是在实质信号内，我们将应用最近开发的压缩感知方法。1

DESCRIPTION (provided by applicant): The overall purpose of this grant application is to further draw on the extensive developments made in contrast-enhanced MR angiography (CE-MRA) during the previous funding cycle and push the field to even higher levels. The last several years have seen multiple developments in CE-MRA, and we believe that the work of our own group has contributed materially to this. Specific developments include: (i) demonstration of a signal enhancement effect when 2D parallel acquisition is applied to elliptical centric CE-MRA; (ii) demonstration of improved vessel sharpness in accelerated CE-MRA; (iii) development of the Cartesian Acquisition with Projection-Reconstruction-like sampling (CAPR) pulse sequence for time-resolved CE-MRA; (iv) routine demonstration of acceleration factors exceeding 10 in CE-MRA; (v) development of modular coil arrays for accelerated CE-MRA; (v) demonstration that CAPR provides high fidelity in the portrayal of dynamic phenomena; and (vi) routine demonstration of high quality time-resolved 3D CE-MR angiograms of the brain and calves. Specific aims to be studied are: 1. High Quality Comprehensive Neurovascular Exam. In an extension of the work performed during Years 20- 23 we will generate high quality images of the vasculature of the aortic arch, carotid arteries, intracranial arteries, and the draining veins of he brain in one comprehensive exam. The traditional test bolus used to assess timing in a 2D slice will be replaced with a low dose (1-2 ml) 3D time-resolved CE-MRA sequence. This will be followed by normal dose (18 ml) acquisition in which multi-element, modular RF coil arrays will allow 2D accelerated acquisition, providing high spatial resolution data sets for all territories. . High Resolution CAPR of the Upper Extremities and Abdomen. Parallel acquisition techniques previously developed for MR angiography of the brain and calves will be adapted to other anatomic regions. For each region the modular coil array elements will be matched to the specific field-of-view (FOV) and desired spatial resolution. For the hands the FOV is typically asymmetric (L/R vs. A/P), suggesting that elements having different sizes be used as for the calves. For the abdomen the increased FOV calls for larger coil elements. 3. Combined Angiographic and Perfusion MR Imaging. Analysis of the signal levels in brain parenchyma from CAPR CE-MRA studies of the brain has shown that first-pass parenchymal "blush" is detectable, suggesting the potential for providing perfusion information from the angiographic data set. However, this can be limited by a frame time which is still marginally too long and SNR which is marginally too small. To address this we will adapt the basic CAPR sequence for improved temporal resolution using 2D SENSE acceleration factors of ten-fold and higher. To retain SNR, particularly within the parenchymal signal, we will apply recently developed compressive sensing methods. 1 PUBLIC HEALTH RELEVANCE: Cardiovascular disease is a major problem in the population of the United States. It is important to image and diagnosis this condition in an easy, accurate, reliable, and safe manner. It is also important to provide images with adequate spatial detail and which can portray progressive blood flow through the vessels. This project is relevant to this problem, as the goal is to develop a method which allows high spatial resolution MR imaging of the vasculature by developing ways to rapidly image the transit of intravenous contrast material within each patient.