Flow Sensitive SSFP for Non-Contrast MRA and Vessel Wall Imaging

描述（由申请人提供）：本提案的广泛、长期目标是改善动脉疾病患者的预后，动脉疾病是美国主要的死亡原因之一。对比增强成像是临床公认的MRA常规方法。然而，肾功能不全的患者在接受钆类药物治疗后，有发展成一种使人衰弱并可能致命的疾病——肾源性全身性纤维化的风险。该项目的目的是开发一种新的非对比增强MRA技术。将分别获得两组心电图触发的心脏相位分辨3D图像，分别使用和不使用流量敏化脱相（FSD）制备。在收缩期，稳态自由进动（SSFP）成像会在动脉和静脉中产生与血流无关的明亮血液信号，而FSD制备获得的图像显示的是黑色的动脉和明亮的静脉，因为FSD制备会对快速流动的动脉血造成严重的信号损失，而对缓慢流动的静脉血和背景组织几乎没有影响。两个图像集的相减将只显示动脉。“黑血”图像也可用于动脉壁评估，量化斑块负担。因此，该技术具有同时进行全身MRA和动脉壁成像的潜力。该项目的具体目标是：(1)开发心脏相位分辨、fsd制备、自门控3D SSFP技术，用于同时进行MRA和动脉壁成像。将执行四项任务：(a)将开发一种自门控方法来消除由于运动（例如，颈动脉MRA期间吞咽和肾脏MRA期间呼吸运动）引起的潜在图像伪影。(b)在血流存在的情况下，SSFP将得到改善，以获得一致的亮血MRA。(c)消防处的准备和数据采集方案将得到优化，以最大限度地提高动脉血液与背景/静脉的对比噪声比，用于颈动脉、肾动脉和外周动脉的MRA和血管壁成像。(d) k-t平行成像将被优化，以提高心脏相位分辨MRA和血管壁成像的速度。(2)验证非对比MRA和血管壁成像技术能够准确描绘动脉狭窄，量化患者斑块负担。三组分别患有颈动脉、肾脏和外周动脉疾病的患者将被研究。对比增强MRA和单排涡轮自旋回波技术将分别作为MRA和壁成像的参考方法。该项目的终点是开发和初步临床验证一种新的非对比增强MRA方法，能够同时进行全身MRA和动脉壁成像。公共卫生相关性：该项目的总体目标是开发一种非对比增强磁共振成像技术，以检测肾功能不全患者的动脉疾病。

DESCRIPTION (provided by applicant): The broad, long-term objective of this proposal is to improve the prognosis of patients with arterial disease, one of the leading causes of death in the United States. Contrast-enhanced imaging is the clinically accepted conventional method for MRA. However, patients with renal insufficiency who receive gadolinium- based agents are at risk for developing a debilitating and a potentially fatal disease known as nephrogenic systemic fibrosis. The purpose of the proposed project is to develop a new non-contrast-enhanced MRA technique. Two sets of ECG-triggered, cardiac phase-resolved 3D images will be acquired with and without flow sensitized dephasing (FSD) preparation, respectively. In systole, steady state free precession (SSFP) imaging generates bright blood signals for both arteries and veins, independent of flow, while images acquired with FSD preparation show black blood arteries and bright blood veins because FSD preparation causes dramatic signal loss to fast flowing arterial blood but has little effect on slow flowing venous blood and background tissue. Subtraction of the two image sets will show arteries only. The "black-blood" images can also be used for arterial wall evaluation to quantify plaque burden. Therefore, this technique has the potential for simultaneous MRA and arterial wall imaging of the entire body. Specific aims of the project are: (1) To develop the cardiac phase-resolved, FSD-prepared, self-gated 3D SSFP technique for simultaneous MRA and arterial wall imaging. Four tasks will be performed: (a) A self-gating method will be developed to eliminate potential image artifacts due to motion (e.g., swallowing during carotid MRA and respiratory motion for renal MRA). (b) SSFP will be improved for consistent bright blood MRA in the presence of flow. (c) FSD preparation and data acquisition schemes will be optimized to maximize contrast to noise ratio between arterial blood and background/vein for MRA and vessel wall imaging in carotid, renal, and peripheral arteries. (d) k-t parallel imaging will be optimized to improve the speed of cardiac phase-resolved MRA and vessel wall imaging. (2) To verify that the non-contrast MRA and vessel wall imaging technique can accurately depict artery stenoses and quantify plaque burden in patients. Three groups of patients with carotid, renal, and peripheral artery disease, respectively, will be studied. Contrast-enhanced MRA and single-slice turbo spin echo techniques will be used as the reference methods for MRA and wall imaging, respectively. The end point of the project is the development and initial clinical validation of a new non-contrast- enhanced MRA approach capable of simultaneous MRA and arterial wall imaging of the entire body. PUBLIC HEALTH RELEVANCE: The overall objective of this project is to develop a non-contrast-enhanced magnetic resonance imaging technique to detect artery disease in patients with renal insufficiency.