Abstract WP54: Defining Acute Ischemic Stroke Tissue Pathophysiology Using Whole Brain 320 Slice Ct Perfusion
Background: Imaging with Computed tomography perfusion (CTP) in acute stroke has recently started to gain ground, however it requires further validation and whole brain CTP scanners are becoming more available. This study aimed to validate the optimal acute ischemic stroke whole brain CTP pathophysiology parameters.
Methods: One hundred and thirteen patients were scanned within 6 hours of ischemic stroke onset with 320 slice CT, which allows concurrent whole brain CTP and dynamic intracranial CT angiography to be derived from the one acquisition. Patients were then followed with a 24 hour MRI sequence that included diffusion weighted imaging (DWI) and dynamic susceptibility weighted perfusion imaging (PWI). Coregistered acute CTP and 24 hour DWI images were then used to define the optimum CTP perfusion threshold for identifying the extent of critically hypoperfused tissue, and infarct core using a pixel based receiver operator curve analysis in patients with and without reperfusion at 24 hours.
Results: A time to peak TTP threshold of +5 seconds from contralateral baseline defined the perfusion lesion (AUC 0.79 CI 0.74-0.83) while a Cerebral blood flow < 50% from contralateral baseline best defined the acute infarct core (AUC 0.75, CI, 0.71-0.79). There was no statistically significant difference between the accuracy of thresholds depending on the level or region of the brain to define tissue pathophysiology.
Discussion: Whole brain CTP can identify critically hypoperfused tissue and the acute infarct core with excellent accuracy, and finally overcomes the major problem of limited slice coverage with CTP with previous generation CT scanners.
- © 2012 by American Heart Association, Inc.