Perfusion Computed Tomography in Transient Ischemic Attack

Background: Diffusion-and perfusion-weighted imaging after transient ischemic attack (TIA) has been well studied, while less data exist on perfusion computed tomographic (PCT) imaging. Objectives: To examine the frequency of PCT abnormalities in patients with anterior circulation TIA and to identify factors associated with the presence of PCT abnormality. Design: Retrospective study. Setting: Academic hospital. Patients: Sixty-five consecutive patients admitted to Rush University Medical Center, Chicago, Illinois, between June 1, 2007, and November 30, 2009, for anterior circulation motor or aphasic TIA in whom PCT was performed. Main Outcome Measures: Using an automated software algorithm, perfusion abnormality was defined as brain tissue associated with a mean transit time greater than 145% of that of the contralateral hemisphere and cerebral blood volume greater than 2.0 mL/100 g. Demographic, risk factor, clinical, radiographic, and in-hospital outcome data were reviewed. Results: Of 65 patients with anterior circulation TIA who underwent PCT (median age, 62.4 years; 49.2% male), 22 (33.8%) had focal perfusion abnormalities. The presence of motor symptoms (95.5% vs 67.4%, P=.01), multiple (>1) episodes (18.2% vs 2.3%, P=.04), ipsilateral arterial stenosis greater than 50% or occlusion (77.3% vs 11.6%, P<.001), large-artery atherosclerosis subtype (59.1% vs 9.3%, P<.001), and subsequent in-hospital events (22.7% vs 0%, P=.001) were more frequent in those with perfusion abnormality. Conclusions: On acutely performed PCT, one-third of patients with hemispheric TIA have perfusion abnormalities. Perfusion abnormality may mark patients at greater risk for subsequent early deterioration. This requires further study.