E1274. Neuroimaging Strategies in the Evaluation of Suspected Posterior Circulation Stroke: What the Radiologist Needs to Know
  1. Julian Sison; Yale School of Medicine
  2. Long Tu; Yale School of Medicine
  3. Aishwarya Pillai; Yale School of Medicine
  4. Ajay Malhotra; Yale School of Medicine
  5. Mehmet Adin; Yale School of Medicine
Dizziness and vertigo are frequently encountered chief complaints in the emergency setting and present a diagnostic dilemma for physicians who are concerned about posterior circulation stroke as the etiology for the patient's symptoms. Detection of strokes, even if small or in the absence of large vessel occlusion, impacts patient outcomes by motivating acute blood pressure control, short-term double anti-platelet therapy, further evaluation for embolic sources, and optimization of secondary prevention of stroke. Posterior circulation stroke is a challenging diagnosis to recognize, with missed diagnosis in as many as 40% of cases. In this exhibit, we will summarize the existing evidence regarding the diagnostic tools for evaluating patients with suspected posterior circulation strokes as well as the downstream impact on patient management and outcomes.

Educational Goals / Teaching Points
We will begin our presentation by discussing the epidemiology and burden of stroke in the posterior circulation of the brain. We discuss the incidence and contributors to (posterior) stroke misdiagnosis. We address imaging examination choices for posterior circulation stroke and their performance metrics with regard to acute vascular pathology as well as early brain ischemic change. Following that, we will discuss evolving paradigms in the detection and management of large vessel occlusion in the posterior circulation. Finally, we will apply the information provided using sample cases demonstrating the value of differing imaging approaches and how differing detection strategies impact downstream management. Our goal is to optimally equip practicing radiologists to optimally interpret neuroimaging and to provide evidence-based recommendations surrounding the evaluation of suspected posterior circulation stroke.

Key Anatomic/Physiologic Issues and Imaging Findings/Techniques
Study types discussed in this presentation include noncontrast CT of the head, CTA of the head and neck, CT perfusion, MRI, MRA, and MR perfusion. We discuss the sensitivity of differing modalities for large vessel occlusion, subtle/early stroke, and the potential for false-reassurance of commonly-used CT and CTA with early posterior circulation stroke. We discuss technical parameters and innovations which have been shown to improve the detection of subtle stroke and may improve patient outcomes.

Our goal is to optimally equip practicing radiologists to provide accurate interpretation and evidence-based recommendations to emergency providers in the evaluation of suspected posterior circulation stroke. We focus particularly on patients presenting with dizziness/vertigo and discuss evolving techniques in stroke detection.