Hemispheric Infarct Volume Prediction by CT perfusion imaging
Objective: The ability to predict infarct volume when evaluating acute stroke patients is difficult. Bolus contrast CT perfusion imaging (CTP) with fast helical scanning, can identify that portion of ischemic brain with vasculature that does not fill with CT contrast. We evaluated the ability of this acute CTP lesion volume to predict final infarct volume. Methods: 18 patients were selected from our acute stroke database. Inclusion criteria were a CT Angiogram within 6 hours of a major stroke-like symptoms, a follow up brain imaging study no later than 30 days and no earlier than 36 hours, no thrombolytic treatment, and a hemispheric infarct. Initial non-contrast CT (NCCT), CTP and follow-up imaging volumes were measured using image analysis software. Results: Volume of infarct as determined by follow-up brain imaging is significantly predicted by CTP volume with a p value <0.001. The slope of the regression line was 2.02 and r2 equal to 0.660. NCCT volume also predicted follow-up infarct volume, p<0.001, slope 2.13 and r2 0.193. Conclusion: The volume of the infarct is surprisingly well predicted by the measured volume of CTP deficit. This occurs despite the variability due to secondary vascular events, edema and spontaneous reperfusion. NCCT also predicts the infarct volume but with much greater variability than the CTP. CT perfusion is a widely available technique to predict final infarct size in the acute setting.