Abstract WMP18: CT Work-Up of Patients Suspected of Acute Ischemic Stroke: Perfusion-CT Adds Value Compared to Clinical Evaluation, Noncontrast Head CT and CT-Angiogram in Terms of Predicting Outcome

Abstract

BACKGROUND AND PURPOSE: To determine whether Perfusion-CT (PCT) adds value to Noncontrast head CT (NCT), CT-Angiogram (CTA) and clinical assessment in patients suspected of acute ischemic stroke. METHODS: We retrospectively reviewed the clinical and imaging data collected in 165 patients with acute ischemic stroke. ASPECTS score was calculated from NCT. CTA was reviewed for site of occlusion and collateral flow score. PCT was used to calculate the volumes of infarct core and ischemic penumbra on admission. Recanalization status was assessed on follow-up imaging. Clinical data included age, time from onset to baseline imaging, time from baseline imaging to reperfusion therapy, time from baseline imaging to recanalization imaging, NIHSS at baseline, treatment type and modified Rankin score (mRS) at 90 days. In a first multivariate regression analysis, we used volume of PCT penumbra and infarct core as outcome, and assessed whether they could be predicted from clinical variables, NCT and/or CTA. In a second multivariate regression analysis, we used mRS at 90 days as outcome, and determined which imaging and clinical variables predicted it best. RESULTS: 165 patients were identified. Mean±SD time from onset to baseline imaging was 6.7±8.7 hrs. 76 had a good outcome (90-day mRS 0-2), 89 had a poor outcome. Mean±SD PCT infarct was 44.8±46.5 ml. Mean±SD PCT penumbra was 47.0±33.9 ml. PCT infarct could be predicted by clinical data, NCT, CTA, and combinations of this data (P<0.05); the best predictive model included the clinical data, plus NCT and CTA. PCT Penumbra could NOT be predicted by clinical data, NCT, and CTA. In terms of predicting mRS at 90 days, all of variables but NCT and CTA were significantly associated with 90-day mRS outcome. The single most important predictor was recanalization status (P<0.001). PCT penumbra volume (P=0.001) was also a predictor of clinical outcome, especially when considered in conjunction with recanalization through an interaction term (P<0.001). CONCLUSION: PCT penumbra represents independent information, which cannot be predicted by clinical, NCT, and CTA data. PCT penumbra is an important determinant of clinical outcome, and adds relevant clinical information compared to a stroke CT work-up including NCT and CTA.