Background: Stroke remains the third leading cause of death and the first leading cause of handicap in adult age in high-income countries even now when causal revascularisation therapy (intervenous (i.v) thrombolysis and endovascular therapy (EVT) has become generally available. I.v. thrombolysis has been implemented as routine treatment within 4.5 hours of symptom onset based on evidence from randomised controlled trials. Treatment benefit is highly dependent on time from symptom onset to treatment and is therefore strongly related to organisational issues including selection of imaging modality. I.v thrombolysis registration was based on trials using non-contrast Computerized Tomography (CT). In, general however, Magnetic Resonance Imaging (MRI) is considered to imply a higher standard of care. MRI is considered to give more detailed information and improve patient safety. The issue if CT or MRI is 'best' in i.v. thrombolysis work-up has been discussed by stroke scientists for more than a decade, both nationally and internationally. MRI is superior in detecting acute ischaemia and CT is quicker; but the effect of choice of imaging modality on overall efficacy and safety remains to be determined in spite of completion of more than 74.000 i.v. thrombolysis treatments in Europe according to the SITS-MOST registry. Access to primary work up by MRI is frequently regarded as a token of high treatment quality; nevertheless, few centres worldwide are really primarily MRI based. CT is much faster and has no contraindications. This may be crucial as the efficacy of thrombolysis decreases with time to treatment - numbers needed to treat increases with 1 for every 20 minutes, making the question if MRI is only of academic interest a relevant question.