Abstract T P173: Cerebral Oxygen Extraction Fraction MRI to Assess Metabolic Changes in Acute Ischemic Stroke
Background: In acute cerebral ischemia, there is an imbalance between oxygen tissue consumption and delivery and oxygen extraction fraction (OEF) from the circulation increases to maintain normal oxygen metabolism and neuronal function. Detecting such metabolic changes may provide important data to inform decisions on therapeutic interventions such as patient selection for reperfusion or identification of futile therapeutic situations. We used serial OEF MRI to assess metabolic changes in brain tissue associated with reperfusion interventions.
Methods: Serial OEF acquired in 10 consecutive cases of acute anterior circulation ischemic stroke at a single center during a 12 month period. Transverse relaxation and static magnetic field inhomogeneity driven relaxation was mapped using multislice gradient echo planar imaging. Data are fitted on a voxel-by-voxel basis to the Yablonskiy and Haacke model to map deoxyhemoglobin concentration and cerebral blood volume.
Results: 10 cases (median age 72 years (IQR 62-77), 5 women) were studied. Median NIHSS score 15.5 (IQR 9-25). 3 patients received no intervention as last known well time exceeded a treatment window. 3 patients received intravenous thrombolysis (IV), 3 patients received IV and mechanical thrombectomy (MT), and 1 patient received MT only. In the IV treated patients, median time to therapy 110. 5 minutes (IQR 80-132). In the MT treated patients, median time to therapy 257 minutes (IQR 234-331). In the untreated patients, the OEF was elevated in the ischemic territory and this appeared to persist at 24 hours. In the treated patients, those who had at least partial recanalization, demonstrated improved OEF in the ischemic territory at 24 hours.
Conclusions: OEF provides a novel method for non-invasive detection of tissue with impaired oxygen delivery in acute stroke patients and is a novel tool for imaging metabolic changes in pathophysiology and disclosing therapeutic opportunities.
Author Disclosures: L.K. Ali: None. J.R. Alger: Ownership Interest; Significant; NeuroSpectroScopics LLC. M.S. Johnson: None. B. Yoo: None. F. Scalzo: None. D.S. Liebeskind: Consultant/Advisory Board; Modest; Stryker, Covidien. Research Grant; Significant; NIH-NINDS.
- © 2015 by American Heart Association, Inc.