Piotr Sobolewski,1 Grzegorz Kozera,2 Wiktor Szczuchniak,1 Walenty M Nyka2 1Department of Neurology and Stroke, Unit of Holy Spirit Specialist Hospital in Sandomierz, Sandomierz, Poland; 2Department of Neurology, Medical University of Gdańsk, Gdańsk, Poland Introduction: Patients with ischemic stroke undergoing intravenous (iv)-thrombolysis are routinely controlled with computed tomography on the second day to assess stroke evolution and hemorrhagic transformation (HT). However, the benefits of an additional computed tomography (aCT) performed over the next days after iv-thrombolysis have not been determined.Methods: We retrospectively screened 287 Caucasian patients with ischemic stroke who were consecutively treated with iv-thrombolysis from 2008 to 2012. The results of computed tomography performed on the second (control computed tomography) and seventh (aCT) day after iv-thrombolysis were compared in 274 patients (95.5%); 13 subjects (4.5%), who died before the seventh day from admission were excluded from the analysis.Results: aCTs revealed a higher incidence of HT than control computed tomographies (14.2% vs 6.6%; P=0.003). Patients with HT in aCT showed higher median of National Institutes of Health Stroke Scale score on admission than those without HT (13.0 vs 10.0; P=0.01) and higher presence of ischemic changes >1/3 middle cerebral artery territory (66.7% vs 35.2%; P1/3 middle cerebral artery (phi=0.03) existed, and the presence of HT in aCT was associated with 3-month mortality (phi=0.03).Conclusion: aCT after iv-thrombolysis enables higher detection of HT, which is related to higher 3-month mortality. Thus, patients with severe middle cerebral artery infarction may benefit from aCT in the decision-making process on the secondary prophylaxis. Keywords: ischemic stroke, iv-thrombolysis, computed tomography, hemorrhagic transformation