Abstract WP219: Whole Brain Perfusion In Tia

Abstract

Transient ischemic attack (TIA) is the major predictor of future ischemic stroke risk. However clinical diagnosis of TIA is extremely inaccurate. We aimed to investigate whole brain perfusion CT as a screening tool for TIA. Methods: Patients presenting to the John Hunter Hospital with a clinical diagnosis of TIA were scanned within 6 hours of symptom onset with 320 slice CT, which allows whole brain perfusion (CTP). Patients then underwent diffusion weighted MRI within 24 hours of symptom onset. A pixel based analysis was undertaken to determine perfusion based anomalies, and correlate findings to the 24 hour DWI lesion. Results: 156 patients with a clinical diagnosis of TIA were enrolled in the study. Whole brain perfusion imaging in 79 patients was normal, 35 patients had a delay time hypoperfusion lesion (>2 seconds compared to normal tissue) > 10mL, and 44 showed hyperperfusion at a threshold of Cerebral blood flow >120% . The volume of the delay 2 seconds lesion was strongly correlated to the acute NIHSS r=0.769 p=0.05. 44 patients had a DWI lesion of >5mL. Most patients with an acute delay 2 seconds lesion would develop a DWI infarct at 24 hours (41 patients, p=0.01). Discussion: Clinical assessments of resolving or mild neurological symptoms are poorly sensitive, and as a result imaging is required. We have shown that acute perfusion imaging findings are a sensitive and specific marker for recent (<24 hours) TIA.