MRI versus CT-based thrombolysis treatment within and beyond the 3 h time window after stroke onset: a cohort study

Lancet Neurol. 2006 Aug;5(8):661-7. doi: 10.1016/S1474-4422(06)70499-9.


Background: Thrombolytic treatment with recombinant tissue plasminogen activator (rtPA) is approved for use within 3 h after stroke onset. Thus only a small percentage of patients can benefit. Meta-analyses and more recent studies suggest a benefit for a subset of patients beyond 3 h. We assessed the safety and efficacy of an MRI-based selection protocol for stroke treatment within and beyond 3 h compared with standard CT-based treatment.

Methods: We assessed clinical outcome and incidence of symptomatic intracerebral haemorrhage (ICH) in 400 consecutive patients treated with intravenous rtPA. Patients eligible for thrombolysis within 3 h were selected by CT or MRI and beyond 3 h only by MRI. 18 patients were excluded from analysis because of violation of that algorithm. The remaining 382 patients were divided into three groups: CT-based treatment within 3 h (n=209); MRI-based treatment within 3 h (n=103); and MRI-based treatment beyond 3 h (n=70).

Findings: Patients in group 3 (MRI > 3 h) had a similar 90 day outcome to those in the other two groups (48% were independent in the CT < or = 3 h group, 51% in the MRI < or = 3 h group, and 56% in group 3), but without an increased risk for symptomatic ICH (9%, 1%, 6%) or mortality (21%, 13%, 11%). MRI-selected patients overall had a significantly lower risk than CT-selected patients for symptomatic ICH (3% vs 9%; p=0.013) and mortality (12% vs 21%; p=0.021). Time to treatment did not affect outcomes in univariate and multivariate analyses.

Interpretation: Our data suggest that beyond 3 h and maybe even within 3 h, patient selection is more important than time to treatment for a good outcome. Furthermore, MRI-based thrombolysis, irrespective of the time window, shows an improved safety profile while being at least as effective as standard CT-based treatment within 3 h.

Publication types

  • Clinical Trial
  • Comparative Study

MeSH terms

  • Aged
  • Aged, 80 and over
  • Cohort Studies
  • Female
  • Humans
  • Magnetic Resonance Imaging*
  • Male
  • Predictive Value of Tests
  • Retrospective Studies
  • Stroke / drug therapy*
  • Stroke / mortality
  • Stroke / pathology*
  • Thrombolytic Therapy*
  • Time Factors
  • Tissue Plasminogen Activator / therapeutic use*
  • Tomography, X-Ray Computed*
  • Treatment Outcome


  • Tissue Plasminogen Activator