Vulnerable Plaque Detection with Carotid Strain Imaging

通过颈动脉应变成像检测易损斑块

• 批准号: 7773096
• 负责人: TOMY VARGHESE
• 金额: $ 22.28万
• 依托单位: UNIVERSITY OF WISCONSIN-MADISON
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-30 至 2011-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7773096
• 关键词: Age; Algorithms; Arterial Fatty Streak; Arteries; Blood; Blood Circulation; Blood flow; Cardiac; Carotid Arteries; Carotid Artery Plaques; Carotid Endarterectomy; Cerebrum; Chemicals; Clinical; Clinics and Hospitals; Control Groups; Critiques; Data; Detection; Discrimination; Embolism; Goals; Grant; Health Care Costs; Image; Imagery; Lateral; Lesion; Lipids; Location; Measurement; Measures; Mechanics; Methods; Morphologic artifacts; Myocardial Infarction; Noise; Operative Surgical Procedures; Pathology; Patient Schedules; Patients; Physiological; Property; Research; Risk; Rupture; Scanning; Screening procedure; Senile Plaques; Signal Transduction; Solutions; Source; Stenosis; Stream; Stress; Stroke; Structure; Therapeutic Embolization; Thrombosis; Time; Tissues; Transient Ischemic Attack; Ultrasonography; Validation; base; human subject; improved; in vivo; indexing; information display; markov model; novel strategies; pressure; programs; public health relevance; radiofrequency; reconstruction; response; tool; vector; volunteer

DESCRIPTION (provided by applicant): Current clinical criteria for treatment of atherosclerotic plaque or atheromas, has focused primarily on percent stenosis of the vessel. However, percent stenosis does not identify plaque prone to rupture that may release emboli into the blood stream of the sensitive cerebral vasculature. These 'vulnerable' plaques are particularly prone to produce sudden major problems, such as a heart attack or stroke. Atheromas become vulnerable if they grow rapidly and have only a thin fibrous cap separating the soft lipid pool and other plaque constituents from the bloodstream. Structural stability of carotid plaque is a result of its chemical composition, cellular material and new vessel formation. Various studies have indicated that pulsatile pressure induced due to blood flow may rupture the thin cap overlying lipid rich lesions, leading to subsequent thrombosis and plaque rupture. Plaque vulnerability is therefore determined primarily by the mechanical (elastic) properties of the vessel wall and plaque composition. Ultrasound-based strain imaging can provide a means of identifying vulnerable plaque. A novel approach to strain imaging, where pulsation of blood through the carotid artery is used to induce tissue displacements for strain imaging, will be developed and evaluated. We propose the use of three 'strain indices' namely; maximum accumulated axial strain, maximum lateral displacement and strain, and shear strains in plaque over the cardiac cycle as measures of plaque vulnerability. To obtain the normal and shear strain tensors, we propose to utilize beam-steered radiofrequency data acquired along different angular insonification directions to compute the displacement vectors and subsequently the strain tensors. We will also incorporate a modified dynamic 2D multi-level cross-correlation method to track local displacements with the angular data acquired. Our preliminary results demonstrate the ability to differentiate between soft and stiffer plaque noninvasively. The long term objectives are to provide a non-invasive measurement of patients at risk for plaque rupture, expanding upon the current criteria for treatment for atherosclerotic risk based on focal transient ischemic attacks or strokes. The limited in-vivo study on patients will be complimented by a similar analysis on a control group of age-matched volunteers to determine the significance of the 'strain indices' for discrimination of vulnerable plaque. Finally, the entire excised plaque core following carotid endarterectomy will be further evaluated using histological analysis at the same in-vivo transverse cross-sections (based on measurements from the flow- divider) where strain imaging was performed to better understand plaque composition and structure (along with microulcerations and neovascularity) to the information displayed on the normal and shear strain images. PUBLIC HEALTH RELEVANCE: Ultrasound-based strain imaging can provide a means of identifying vulnerable plaque. A novel approach to strain imaging, where pulsation of blood through the carotid artery is used to induce tissue displacements for strain imaging, will be developed and evaluated. One of the goals of this research is to help determine patients at risk for stroke, while excluding patients with manageable risk from undergoing surgery, both of which would dramatically reduce healthcare costs.

描述（由申请人提供）：治疗动脉粥样硬化斑块或动脉瘤的当前临床标准主要集中在血管狭窄百分比上。但是，狭窄百分比并未识别出可能破裂的斑块，可能会释放出栓子进入敏感大脑脉管系统的血液。这些“脆弱”斑块特别容易产生突然的重大问题，例如心脏病发作或中风。如果动脉瘤快速生长，并且只有一个细纤维帽，将软脂质池和其他斑块成分与血液分开。颈动脉斑块的结构稳定性是其化学成分，细胞材料和新容器形成的结果。各种研究表明，由于血流引起的脉动压力可能破裂，薄薄的蛋白质含量富含脂质的病变，从而导致血栓形成和斑块破裂。因此，斑块脆弱性主要取决于容器壁和斑块组成的机械（弹性）特性。 基于超声的应变成像可以提供识别脆弱牌匾的方法。一种新型的应变成像方法，其中将开发和评估通过颈动脉脉动通过颈动脉诱导组织位移来进行菌株成像。我们建议使用三个“应变指数”。最大累积轴向应变，最大的侧向位移和应变以及心脏周期中斑块中的剪切菌株，作为斑块脆弱性的测量。为了获得正常和剪切应变张量，我们建议利用沿不同的角度隔离方向获得的光束向导射频数据，以计算位移向量，然后将应变张量张紧器计算。我们还将结合一种修改的动态2D多级互相关方法，以通过获取的角度数据跟踪局部位移。我们的初步结果证明了无创区分软斑块和更硬的斑块的能力。长期目标是提供对处于斑块破裂风险的患者的非侵入性测量，从而扩展了基于焦点短暂性缺血性发作或中风的当前治疗方法的动脉粥样硬化风险的标准。对对照组匹配的志愿者的对照组进行类似分析，以确定“应变指数”对区分弱势斑块的重要性，将对患者的体内研究有限。 最后，将在相同的体内横截面（基于来自流量分离器的测量值）处进行颈动脉内膜切除术后整个切除的斑块核心，以便更好地了解斑块组成和结构（基于流量分离器的测量值）（基于来自流量分离器的测量值）（基于。以及在正常和剪切应变图像上显示的信息以及微观量和新生血管。 公共卫生相关性：基于超声的应变成像可以提供识别脆弱牌匾的方法。一种新型的应变成像方法，其中将开发和评估通过颈动脉脉动通过颈动脉诱导组织位移来进行菌株成像。这项研究的目标之一是帮助确定有中风风险的患者，同时不包括接受手术的患者，这两者都会大大降低医疗保健费用。