EARLY DETERMINATION OF STROKE SUBTYPE--CT ANGIOGRAPHY

候选人是一名中风研究员训练有素的神经学家，致力于急性中风的诊断和治疗。本申请提出了一个全面的方案，旨在发展候选人成为一个独立的研究者在病人为导向的中风研究。宾夕法尼亚大学拥有出色的临床、放射学和流行病学资源来支持这一建议。该计划的培训部分包括临床流行病学和研究设计方面的正式研究生教育，特别侧重于血管疾病和技术评估。研究部分是在中风管理的背景下，一个新的诊断工具的前瞻性评价。该研究计划的中心假设是早期临床确定卒中机制是有限的，但计算机断层扫描血管造影（CTA）将有效地识别具有特定卒中机制的患者，并针对特定机制进行治疗。缺血性中风可能由几种不同的病因之一引起，治疗可能最好针对潜在的机制。急性中风的治疗必须在中风发作后的最初几个小时内开始，但目前确定中风机制的方法在这一关键时期是不准确的。确定脑卒中机制的金标准方法需要在治疗时间窗内无法获得彻底的评估。新的成像技术可能有助于早期确定脑卒中亚型，但在脑卒中分类和治疗方面还没有正式的分析。CTA是一种非常有前途的新技术，它是一种快速、无创的方法，可以对脑血管系统进行可视化。具体目的：CTA在缺血性脑卒中亚型早期诊断中的作用将通过测量其阳性预测值（主要结局指标）、敏感性、特异性和可靠性来确定。我们假设CTA的这些特征优于目前的临床脑卒中诊断方法。基于cta的脑卒中机制诊断将与早期临床诊断进行比较，并最终与金标准最终诊断进行比较。150例患者将在中风发作后24小时内接受CTA检查。研究者将根据现有的临床信息对卒中机制进行早期评估，并对CTA结果不知情。在完成诊断评估后，卒中机制将最终确定。然后，研究人员将使用临床和CTA数据来确定基于CTA的诊断。将比较临床诊断和基于cta诊断的阳性预测值（PPV），并对多评分者和多患者进行调整。该方法将首次正式评估CTA作为早期卒中诊断和选择具有特定卒中机制的患者进行特定机制定向卒中治疗的工具。

The candidate is a stroke fellowship-trained neurologist dedicated to a career in acute stroke diagnosis and treatment. This application proposes a comprehensive program designed to evolve the candidate into an independent investigator in patient- oriented stroke research. The University of Pennsylvania has outstanding clinical, radiological, and epidemiological resources to support this proposal. The training component of this plan entails formal graduate education in clinical epidemiology and research design, specifically focusing on vascular disease and technology assessment. The research component is a prospective evaluation of a new diagnostic tool in the context of stroke management. The central hypothesis of the research proposal is that early clinical determination of stroke mechanism is limited, but computed tomography angiography (CTA) will effectively identify patients with specific stroke mechanisms for specific mechanism- directed therapies. Ischemic stroke may be caused by one of several different etiologies, and treatment may be best directed toward the underlying mechanism. Therapy for acute stroke must be initiated in the first few hours after stroke onset, but current methods for identifying stroke mechanism are inaccurate during this critical time period. The gold standard method for determination of stroke mechanism requires a thorough evaluation that cannot be obtained within the therapeutic time window. New imaging techniques may be useful for the early determination of stroke subtype, but there has been no formal analysis of their utility in stroke triage and treatment. An extremely promising novel technique is CTA, a quick noninvasive method that allows for visualization of the cerebral vasculature. Specific Aims: The role of CTA in the early diagnosis of ischemic stroke subtype will be determined by measuring its positive predictive value (primary outcome measure), sensitivity, specificity, and reliability. We hypothesize that these characteristics are superior for CTA than current methods of clinical stroke diagnosis. CTA-based diagnosis of stroke mechanism will be compared with early clinical diagnosis, and ultimately will be compared with the gold standard final diagnosis. A cohort of 150 patients will be examined with CTA within 24 hours of the onset of stroke. Investigators will make an early assessment of stroke mechanism based on the available clinical information and will be blinded to CTA results. Stroke mechanism will ultimately be established after a diagnostic evaluation is completed. Investigators will then use both clinical and CTA data to determine a CTA-based diagnosis. The positive predictive value (PPV) of the clinical and CTA-based diagnoses will be compared, adjusting for multiple raters and multiple patients. This approach will, for the first time, formally evaluate CTA as a tool for early stroke diagnosis and selection of patients with specific stroke mechanisms for specific mechanism-directed stroke therapies.