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)：目前治疗动脉粥样硬化斑块或动脉粥样硬化的临床标准主要集中在血管的狭窄程度。然而，狭窄百分比并不能确定容易破裂的斑块，这些斑块可能会将栓子释放到敏感脑血管系统的血流中。这些“脆弱的”斑块特别容易产生突发的重大问题，如心脏病发作或中风。如果动脉粥样硬化瘤生长迅速，并且只有一层薄薄的纤维帽将软脂池和其他斑块成分与血流隔开，就会变得脆弱。颈动脉斑块的结构稳定性是其化学成分、细胞物质和新生血管形成的结果。各种研究表明，血流引起的脉动压可能会破坏覆盖在富脂病变上的薄帽，导致随后的血栓形成和斑块破裂。因此，斑块的脆弱性主要由血管壁和斑块成分的机械(弹性)性质决定。基于超声的应变成像可以提供一种识别脆弱斑块的方法。将开发和评估一种新的应变成像方法，其中通过颈动脉的血液脉动来诱导组织位移以进行应变成像。我们建议使用三个‘应变指数’，即：最大累积轴向应变、最大侧向位移和应变以及心动周期内斑块中的剪切应变作为斑块易损性的衡量标准。为了得到法向应变张量和剪切应变张量，我们建议利用沿不同角度光化方向获得的束控射频数据来计算位移矢量以及随后的应变张量。我们还将结合一种改进的动态2D多层互相关方法来跟踪获取的角度数据的局部位移。我们的初步结果证明了非侵入性区分软斑块和硬斑块的能力。长期目标是提供对斑块破裂风险患者的非侵入性测量，扩展基于局灶性短暂性脑缺血发作或中风的动脉粥样硬化风险治疗的当前标准。除了对患者进行有限的体内研究外，还将对年龄匹配的控制组志愿者进行类似的分析，以确定“应变指数”对区分脆弱斑块的意义。最后，颈动脉内膜切除术后切除的整个斑块核心将在相同的体内横截面上进行组织学分析(基于分流仪的测量)，以更好地了解斑块的组成和结构(以及微溃疡和新生血管)，以更好地了解正常和剪切应变图像上显示的信息。 公共卫生相关性：基于超声波的应变成像可以提供一种识别脆弱斑块的方法。将开发和评估一种新的应变成像方法，其中通过颈动脉的血液脉动来诱导组织位移以进行应变成像。这项研究的目标之一是帮助确定中风风险的患者，同时排除风险可控的患者接受手术，这两者都将极大地降低医疗成本。