Diagnostic accuracy of whole-brain computed tomography perfusion for detection of ischemic stroke in patients with mild neurological symptoms

Mild and minor acute neurological symptoms may lead to diagnostic uncertainty, resulting in a heterogeneous group of patients with true ischemic events and stroke mimics with a potential for poor outcomes. More than half of ischemic stroke patients present as minor strokes (National Institutes of Health Stroke Scale score <6). Whole-brain computed tomography perfusion can be used as a diagnostic test for minor stroke, offering a potential method of reducing diagnostic uncertainty in these patients. We hypothesize that whole-brain computed tomography perfusion imaging features could accurately predict infarction in patients with minor neurological deficits. This retrospective chart review enrolled consecutive patients suspected of acute ischemic stroke with a National Institutes of Health Stroke Scale score <6, who underwent whole-brain computed tomography perfusion and follow-up diffusion-weighted magnetic resonance imaging at our institution. Sensitivity, specificity, positive and negative predictive values, and positive and negative likelihood ratios were calculated for whole-brain computed tomography perfusion, using follow-up diffusion-weighted magnetic resonance imaging as a reference standard. A total of 524 patients (mean age: 67 years; range: 17-96 years; 56% men) met the inclusion criteria. Patients were excluded for non-diagnostic (n = 25) or missing maps (n = 8) scans, non-ischemic findings (n = 7), and lack of follow-up magnetic resonance imaging (n = 336). The final analysis included 148 patients who underwent diffusion-weighted magnetic resonance imaging. Whole-brain computed tomography perfusion has a sensitivity of 0.57 (95% CI: 0.45-0.69) and a specificity of 0.82 (95% CI: 0.71-0.90). The positive and negative predictive values and positive and negative likelihood ratios were 75%, 67%, 3.09, and 0.53, respectively. Our analysis suggests that although whole-brain computed tomography perfusion may offer some value as an adjunctive test for improving confidence in offering stroke treatment, it is not sufficiently sensitive or specific to accurately predict cerebral infarcts in patients with minor neurological symptoms.