Project Summary/Abstract Stroke is the 5th leading cause of death in the United States. Endovascular stroke therapy (EST) has revolutionized the management of large vessel occlusion (LVO) acute ischemic stroke (AIS), which accounts for a disproportionate amount of disability in stroke. While this therapy has been shown to significantly improve clinical outcomes in multiple clinical trials, these studies nearly all required screening patients with advanced NeuroImaging such as CT Perfusion (CTP), a modality not available to the majority of community hospitals. As such, there is a pressing need to for a tool able to identify EST candidates leveraging the infrastructure already existing in community hospitals. We envision a software-based service to automate the NeuroImaging evaluation for EST using CT angiography (CTA). We developed and tested a prototype of a novel deep neural network architecture called DeepSymNet. Our preliminary data indicate that uniquely using CTAs we can determine (1) the presence or absence of a large vessel occlusion (2) if the extent of ischemic core and (3) volume of tissue “at risk” (penumbra) is above or below the thresholds used in the clinical trials, when compared to concurrently obtained results using CTP. We will pursue our project goal with three aims: - Aim 1 - Establish one of the largest multi-institution dataset for neuro-imaging research in acute ischemic stroke. We will acquire a multi-center dataset including imaging and clinical data from 15 hospitals across Texas and California, from a range of scanners, imaging acquisition protocols, and hospital types (i.e. large academic and smaller community). - Aim 2 - Develop interpretable deep learning models to determine the eligibility for EST. We will methodically test a set of model architectures, data augmentation strategies, loss functions and pre-processing steps based on DeepSymNet. We will train and test the algorithm against various definitions of infarct core and penumbral volume based on CTP results. This approach will allow for models adaptable to the everchanging definition of EST eligibility. – Aim 3 - Evaluate the external validity of DeepSymNet-based models on a large multi-center independent dataset. To accomplish this aim, we will deploy our DeepSymNet software on patient imaging and data from multiple hospitals, which were not used in the creation of the software. We will also validate our approach of using CTA alone to determine ischemic core by validating blinded reads of infarct core from CTA source images performed by expert readers against concurrently acquired CTP results. Completion of these aims will have a sustained, transformative impact by supporting the creation and validation of decision support tools readily translatable to the patient bedside in the vast majority of community hospitals across the country. In doing so, we hope to expand the access to high-quality EST screening to thousands of additional AIS patients.

PROJECT NARRATIVE With endovascular stroke therapy, we now have the ability to dramatically improve patient outcomes after stroke. To date, however, screening for patients that may benefit from this procedure has been relegated to larger academic centers, as the advanced imaging modalities required for this evaluation are not widely available. The goal of our proposal is to develop and validate machine learning-based software tools to identify patients eligible for endovascular stroke therapy using CT angiography, an imaging modality readily available in the vast majority of community hospitals.