Abbreviated Cardiovascular MRI for Enhanced Etiology Diagnosis in Acute Ischemic Stroke Patients

About This Grant

ABSTRACT The overarching goal of this project is to develop an abbreviated cardiovascular magnetic resonance (aCMR) imaging solution for time-efficient, cost-effective etiology diagnosis of acute ischemic stroke (AIS). Stroke is the second leading cause of death and the third leading cause of disability worldwide. About 87% of all strokes are ischemic. Causes of AIS include large artery atherosclerosis, small artery disease, cardioembolism, and some unusual conditions (e.g., hypercoagulability and dissection). Rapidly and correctly identifying the cause of AIS is crucial for treatment decisions to prevent stroke recurrence. However, the routine etiology workup for AIS remains limited. First, standard evaluation, including history collection, physical examination, laboratory tests, and step-wise imaging workup, fails to identify a definitive cause in 20-30% of ischemic strokes, leading to a diagnosis of cryptogenic stroke. Second, etiology classification based on standard evaluation may be incorrect, with reported misclassification rates ranging from 14% to 55%. Third, although advanced evaluation may be pursued at specialized stroke centers when standard evaluation fails, the rate of cryptogenic strokes remains as high as 10-15%, also underscoring the need for further technical innovation. Nevertheless, the overall multi-step, multi-modality imaging paradigm in the current stroke etiology workup inevitably extends the diagnostic timeline, delays the initiation of effective intervention, and imposes a substantial burden on both patients and the healthcare system. MR has shown great potential for multi-station etiology evaluation, particularly within one examination, which would substantially complement and expedite the current diagnostic workup. To address the above unmet clinical needs, we will develop a 10-minute-long aCMR solution that can be seamlessly integrated into the initial brain MR examination typically performed 24-48 hours after AIS admission. It features two-station scanning (based on our novel joint head-neck vessel wall imaging technique and joint heart-aorta multi- dimensional imaging technique), superb image contrast and time efficiency, and a light-weight blanket carotid- chest coil design for easy patient setup, which will collectively contribute to invaluable multifaceted diagnostic information with minimal interference with the current workflow. This project will deliver two optimized MR techniques as the core of aCMR in Aim 1 followed by a clinical study to assess its impact on stroke etiology diagnosis in Aim 2. Abbreviated MR protocols have gained popularity in other fields due to their cost- effectiveness, yet no such protocol currently exists for stroke etiology evaluation. This project will fill this critical gap by pioneering a streamlined, high-impact approach. If successfully validated, the aCMR-based imaging paradigm is expected to significantly enhance AIS care by improving the accuracy and efficiency of etiology diagnosis, reducing rates of cryptogenic stroke diagnosis, and effectively guiding treatment decisions for secondary stroke prevention.