MRI based thrombolysis for FLAIR-negative stroke patients within 4.5-6h after symptom onset.

To investigate the feasibility of DWI-FLAIR mismatch in identifying patients who might benefit from thrombolytic therapy within 4.5-6h, we analyzed the data of 105 ischemic stroke patients with known time of symptom onset who underwent MRI within 6h of stroke and thrombolysis between December 2006 and December 2013. They were divided into three groups: symptom onset within 4.5h (n=66); 4.5-6h and FLAIR images negative (n=9); and 4.5-6h and FLAIR images positive (n=30). Outcome of thrombolysis was assessed for each group by recanalization rate, National Institutes of Health Stroke Scale (NIHSS) and modified Rankin Scale (mRS) scores. The results showed that mismatch between positive DWI and negative FLAIR images identified patients within 4.5h of symptom onset with sensitivity, specificity, positive predictive value and negative predictive value of 40.9%, 76.9%, and 75% and 43.5%. Recanalization rate, NIHSS score and mRS score were all better in both the 0-4.5h and 4.5-6h FLAIR-negative groups than in the 4.5-6h FLAIR-positive group (p<0.05). These data demonstrate that within 4.5-6h of symptom onset, patients with negative FLAIR images may benefit from thrombolysis therapy.