Abstract 2: Extensive Collateral Recruitment after Intravenous Thrombolysis in Acute Ischemic Stroke is Associated with Symptomatic Intracranial Haemorrhage

Background: Various collateral channels are recruited to provide alternative pathways in acute ischemic stroke (AIS), however the relationship with patient outcomes remain unclear. We compared various existing methods of scoring collaterals on the pre-treatment and day-2 computed tomographic angiogram (CTA) of the brain in thrombolyzed AIS patients. Methods: We included 115 consecutive patients in whom CTA was performed both pre-tPA and on day-2. Intracranial collaterals were evaluated by 2 independent neuroradiologists using 4 existing and one modified method- Miteff’s system (grades middle cerebral artery (MCA) collateral branches with respect to sylvian fissure); Maas system (compares collaterals in affected hemisphere against the contralatral side); Modified Tan’s scale (collaterals in 50% or more of MCA territory classified as good); and 20-point collateral grading scale by Alberta Stroke Program Early CT score (ASPECTS) methodology. For the modified scoring system we adapted ASPECTS methodology into...