Caveats to Consider for CT Angiography and Perfusion Weighted Imaging for Stroke Management in the Setting of Venoarterial Extracorporeal Membrane Oxygenation

Objective: Our goal is to highlight the novel challenges in interpretation of computed topography angiography and perfusion (CTA-P) imaging in the setting of venoarterial extracorporeal membrane oxygenation (VA-ECMO) when obtained for acute stroke evaluation. Background: During VA-ECMO with a femoral-femoral cannula arrangment, blood is injected in a retrograde manner from the descending aorta, up the arch, to its branch neck vessels. Intact cardiac function or excessive antegrade flow causes unopacified blood from the heart to oppose contrasted blood flow into the aorta and neck vessels, altering opacification. In the axillary-femoral arrangement, we examine a case with excessive antegrade flow inhibiting contrast from entering the right common carotid. Design/Methods: This is a case report describing the CTA-P imaging obtained on a patient on VA-ECMO with a femoral-axillary configuration. Results: A 20-year-old woman with a history of chronic congestive heart failure, with catastrophic anti-phospholipid syndrome developed acute decompensated heart failure after cesarean delivery requiring VA-ECMO. Post-ECMO cannulation, the patient had a transient episode of right gaze deviation and extensor posturing. A CTA-P was obtained, demonstrating increased time to peak, decreased cerebral blood flow and volume in the right middle cerebral artery (MCA) and anterior cerebral artery (ACA) territorities with no contrast opacification in the right ACA, MCA, brachiocephalic, and common carotid arteries. However, no focal weakness or persistent gaze deviation was clinically present. Carotid Duplex ultrasound demonstrated flow in the right carotid, and transcranial Doppler ultrasound showed normal flow velocities throughout the right MCA. Within 48 hours, VA-ECMO was discontinued. Repeat CTA-P demonstrated normal flow pattern and perfusion, and MRI brain revealed absence of territorial R MCA or ACA territory infarcts. The patient was discharged home with a normal neurologic exam at her outpatient follow-up appointment. Conclusions: As ECMO becomes more commonplace, it is necessary to be familiar with the limitations and artifacts of CTA-P in context. Disclosure: Dr. Viamonte has nothing to disclose. Dr. Nagae has nothing to disclose. Dr. Youn has nothing to disclose. Dr. Simpkins has nothing to disclose.