Computed tomography and computed tomography angiography findings predict functional impairment in patients with minor stroke and transient ischaemic attack

Introduction Abnormalities on acute magnetic resonance imaging predict outcome in minor stroke and transient ischaemic attack patients. We hypothesised that noncontrast computed tomography and computed tomography angiography findings in minor stroke and transient ischaemic attack patients would also predict functional outcome. Methods We analysed consecutive patients with a transient ischaemic attack or a minor stroke with an National Institute of Health Stroke Scale <= 3 who were assessed with a noncontrast computed tomography and CT angiography of the circle of Willis and neck within 24 h of symptom onset. We assessed the association between clinical or imaging features and functional impairment on the modified Rankin Scale (mRS >= 2) at 90 days. Results Among 457 patients, the median baseline National Institute of Health Stroke Scale score was 1. Median time from symptom onset to noncontrast computed tomography was 278 min (interquartile range 151-505) and median delay from noncontrast computed tomography to CT angiography was 3 min (interquartile range 0-13). At 90 days, 57 patients (12.5%) had a mRS >= 2. Clinical factors that were associated with functional impairment were age >= 60 years (RR 2.05 CI(95) 1.16-3.64) and baseline National Institute of Health Stroke Scale score > 0 (RR 3.23 1.72-6.06). All the assessed computed tomography parameters (acute stroke on noncontrast computed tomography and intracranial or extracranial stenosis or occlusion) were individually predictive of functional impairment. A composite computed tomography imaging 'at risk' metric, defined by acute stroke on noncontrast computed tomography, Circle of Willis intracranial vessel occlusion or >= 50% stenosis, extracranial occlusion or >= 50% stenosis, was associated with poorer outcome (RR 2.92 CI(95) 1.81-4.71). Conclusions The presence of an acute stroke on noncontrast computed tomography or an intracranial or extracranial occlusion or stenosis was associated with an increased risk of functional impairment. Multi-modal computed tomography could be used to identify high-risk transient ischaemic attack or minor stroke patients.