Project Summary/Abstract Stroke has a significant health impact and presents an ongoing challenge for the health of the population and the availability of healthcare resources. Imaging plays a critical role in both diagnosis and treatment decisions in acute ischemic stroke. However, optimal strategies regarding advanced imaging with angiography and perfusion using either CT (CTAP) or MR (MRAP) remain uncertain according to national guide- lines. Consequently, inefficient imaging practices have evolved with marked increased utilization of advanced imaging. Wide variations in stroke imaging also exist in clinical practice, mostly defaulted to physician preferences and institutional factors, without a clear understanding of the benefits and risks involved in stroke care. The main concern is that inefficient imaging leads to time-delays to treatment and potentially worse outcomes. Although CTAP and MRAP each have unique benefits and risks in the acute stroke setting, the effect of this risk-benefit tradeoff on health outcomes and utilization of resources is unknown. The problem is this lack of outcomes-based evidence results in wide variations and inefficient imaging practices in stroke care, directly affecting utilization of resources and costs, but more importantly affecting treatment decisions, time-delays and health outcomes. Unfortunately, no efforts to-date have been effective in moving beyond this as the status-quo because significant knowledge gaps exist in understanding how different imaging strategies affect stroke outcomes given the unique risk-benefit tradeoffs of advanced imaging with either CTAP or MRAP in the acute stroke setting. The overall objective of this proposal is to compare the effectiveness of imaging strategies in acute ischemic stroke employing decision science methods to assess the risk-benefit tradeoffs on health outcomes, utilization of resources (imaging and treatment) and costs. Our central hypothesis is that health outcomes will be improved and healthcare resources used most efficiently when advanced imaging (CTAP or MRAP) is selected according to specific patient profiles, defined by characteristics known to impact stroke outcomes such as age, clinical stroke severity and symptom onset time. We will perform the following specific aims: (1) Update trends in stroke health outcomes, quality metrics, utilization of resources and costs, (2) Develop new imaging recommendations tailored to patient profiles based on stroke outcomes, and (3) Quantify the potential impact of the new imaging recommendations on health outcomes, utilization of resources and costs in an ideal model-based scenario compared to current real- world practice. Our deliverables are innovative imaging recommendations tailored to patient profiles in acute ischemic stroke with comprehensive model evaluation of the potential impact on health outcomes and utilization of resources, providing critical safety, feasibility and efficacy data prior to imp...