Objective To use the CT Perfusion (CTP) parameters at the time of hospital admission, including Cerebral Blood Volume and Permeability Surface area product (PS), to identify patients with higher risk to develop hemorrhagic transformation in the setting of acute stroke therapy with intravenous thrombolysis.

Methods Retrospective study that compared admission CTP variables between patients with Hemorrhagic Transformation (HT) acute stroke and those with no hemorrhagic transformation. Both groups received standard of care intravenous thrombolysis with tPA. Twenty patients presented to our stroke center between the years 2007 and 2011 within 3 h after stroke symptoms onset. All patients underwent two-phase 320 slice CTP which creates Cerebral Blood Volume and PS measurements. Patients were divided into two groups according to whether or not they had HT on a follow-up CT head without contrast, done within 36 h of the thrombolysis therapy. Clinical, demographic and CTP variables were compared between the HT and non-HT groups using logistic regression analyses.

Results HT developed in 8 (40%) patients. Patients with HT had lower ASPECT score (p=0.03), higher NIHSS on admission (p=0.01) and worse outcome (p=0.04) compared to patients who did not develop HT. Baseline blood flow defects were comparable between the two groups. The mean PS for the HT group was 0.53 ml/min/100 g brain tissue, which was significantly higher than that for the non-HT group of 0.04 ml/min/100 g brain tissue (p<0.0001). The mean area under the curve was 0.92 (95% CI). The PS threshold of 0.26 ml/min/100 g brain tissue had a sensitivity of 80% and a specificity of 92% for detecting patients with high risk of hemorrhagic transformation after intravenous thrombolysis.

Conclusions Admission CTP measurements might be useful to predict patients who are at higher risk to develop hemorrhagic transformation after acute ischemic stroke therapy.

Competing interests T Kass-Hout: Genentech. O Kass-Hout: None. M Al Masry: None. M Mokin: None. D Wack: None. E Nourollahzadeh: None. A Siddiqui: NINDS 1R01NS064592-01A1, University at Buffalo. Shurtleff, Inc, Concentric Medical, ev3/Covidien Vascular Therapies, GuidePoint Global Consulting, Penumbra. Codman & Shurtleff, Inc, Genentech. Hotspur, Intratech Medical, StimSox, Valor Medical. Abbott Vascular, American Association of Neurological Surgeons, Neocure Group LLC, an Emergency Medicine Conference. E Levy: Codman & Shurtleff, Inc, ev3/Covidien Vascular Therapies, Boston Scientific. TheraSyn Sensors, Inc. Medical Ltd., Mynx/Access Closure. Boston Scientific. K Synder: Toshiba and ev3.