EXtending the Time Window for Thrombolysis in Posterior Circulation Stroke Without Early CT Signs

Inclusion criteria

• . Patients presenting with clinical signs of acute ischemic stroke between 4.5 and 24 hours from stroke onset, or wake-up stroke and unwitnessed stroke (if the midpoint of the last known well time is within 4.5 to 24 hours)
• . Patients aged \> 18 years (or as per local requirements)
• . NIHSS ≥ 1
• . Patients with a posterior circulation ASPECT score (PC-ASPECTS) ≥ 7. If MRI is performed first and the PC-ASPECTS on diffusion-weighted imaging (DWI) is ≥ 7, a non-contrast head CT is not required. If PCASPECTS on DWI is \< 7, the subsequent non-contrast CT must show a PC-ASPECTS ≥ 7 for inclusion
• . Posterior circulation stroke confirmation criteria: If MRI is performed, infarction confirmed by DWI is sufficient. If CT is performed, the non-contrast CT scan must not refute posterior circulation stroke, and clinical signs and symptoms must support the diagnosis, as confirmed by experienced clinicians. If clinical symptoms are atypical, CTA showing symptomatic stenosis or occlusion of large posterior circulation vessels, or CT perfusion showing symptomatic hypoperfusion, can provide additional evidence, though advanced imaging is not mandatory