E1010. Put Down the tpA! Ischemic Infarct Double-Takes
  1. Kyle Stumetz; Dartmouth-Hitchcock Medical Center
  2. Kyung Lee; Dartmouth-Hitchcock Medical Center
  3. Stephen Guerin; Dartmouth-Hitchcock Medical Center
  4. Clifford Eskey; Dartmouth-Hitchcock Medical Center
Ischemic stroke is a leading cause of morbidity and mortality in the developed world. The goals of imaging evaluation for acute ischemic stroke are to establish a rapid diagnosis as early as possible and to obtain accurate information about the intracranial vasculature and brain parenchymal perfusion to facilitate rapid life-saving interventions. However, in as many as one-third of cases, new sudden neurologic deficits can represent “stroke mimics” instead of true vascular occlusions. In each of these cases, it is vital that radiologists are aware of the wide range of benign and pathologic entities that may masquerade as acute thrombotic occlusions and that they are able to recognize common pitfalls in computed tomography angiography (CTA) and computed tomography perfusion (CTP) imaging. A comprehensive understanding of these concepts is vital to preventing overutilization of high-risk medications and unnecessary endovascular interventions. The goal of the present educational exhibit is to review classic imaging findings and pitfalls in acute stroke imaging and to identify a wide both normal and pathologic entities that commonly present as stroke mimics, both clinically and during radiologic evaluation.

Educational Goals / Teaching Points
Review CT, CT angiography (CTA), & CT perfusion (CTP) imaging in the workup of acute ischemic stroke. Explain commonly encountered pitfalls in CTA and CTP imaging. Review diffusion-weighted MR imaging and establish a differential diagnosis for restricted diffusion. Identify common ischemic infarct mimics, vascular anomalies, and variants in which thrombolytic treatment is not indicated via a case-based approach.

Key Anatomic/Physiologic Issues and Imaging Findings/Techniques
Anatomic/pathologic issues (acute ischemic stroke. acute ischemic stroke mimics). Vascular entities covered include congenital anomalies, AVM, venous thrombosis, parenchymal hemorrhage. Infectious/Inflammatory entities covered include moya moya, demyelinating disease, ADEM, PRES, HSV encephalitis. Other entities covered include epilepsy and post-seizure edema, high grade glioma, fat embolism syndrome, hypoglycemia, MELAS syndrome. Imaging Techniques (computed tomography, CT angiography, CT perfusion, conventional angiography, and magnetic resonance imaging).

Rapid diagnostic evaluation of acute ischemic stroke and mimics on radiologic imaging are of critical importance toward selecting patients for whom life-saving interventions would be beneficial. It is important that radiologists understand potential pitfalls of imaging modalities used in stroke workups in addition to identifying common conditions that mimic acute thrombotic occlusion.