 NOR-SASS aims at testing contrast enhanced sonothrombolysis in all patients with acute ischemic stroke. Patients eligible for thrombolysis randomized tenecteplase or alteplase are included in the NOR-SASS A sub-study, patients receiving standard non-trial thrombolysis with alteplase are included in the NOR-SASS B sub-study, and patients not eligible for thrombolysis are included in the NOR-SASS C sub-study. 