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

描述（由申请人提供）：该提案的广泛、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死亡原因之一。对比增强成像是临床公认的MRA常规检查方法。然而，接受钆基药物治疗的肾功能不全患者有发生衰弱和潜在致命疾病（称为肾源性系统性纤维化）的风险。该拟议项目的目的是开发一种新的非对比度增强MRA技术。将分别采集两组ECG触发的心脏相位分辨3D图像（有和无流量敏感失相（FSD）准备）。在心脏收缩期，稳态自由旋进（SSFP）成像生成动脉和静脉的明亮血液信号，与血流无关，而使用FSD制备获得的图像显示黑色血液动脉和明亮血液静脉，因为FSD制备导致快速流动的动脉血液的显著信号损失，但对缓慢流动的静脉血液和背景组织几乎没有影响。两个图像集相减将仅显示动脉。“黑血”图像也可用于动脉壁评估，以量化斑块负荷。因此，该技术具有同时进行全身MRA和动脉壁成像的潜力。本课题的具体目标是：（1）建立心脏相位分辨、FSD制备、自门控的三维SSFP技术，用于同时进行MRA和动脉壁成像。将执行四项任务：（a）将开发一种自选通方法，以消除由于运动（例如，颈动脉MRA期间的吞咽和肾脏MRA的呼吸运动）。(b)SSFP将得到改善，以在存在血流的情况下获得一致的亮血MRA。(c)将优化FSD准备和数据采集方案，以最大化动脉血与背景/静脉之间的对比度噪声比，用于颈动脉、肾动脉和外周动脉中的MRA和血管壁成像。(d)将优化k-t并行成像，以提高心脏相位分辨MRA和血管壁成像的速度。(2)验证非增强MRA和血管壁成像技术能够准确描述患者的动脉狭窄并量化斑块负荷。将分别研究三组颈动脉、肾脏和外周动脉疾病患者。对比增强MRA和单层快速自旋回波技术将分别用作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：本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.