ABSTRACT
Objective To explore whether fluid-attenuated inversion recovery can be used to estimate the onset time of acute ischemic stroke (ALS) based on the analysis of signal strength through the fluid-attenuated inversion-recov?ery (FLAIR)and volume of interest (ROI) in ALS patients with known time of onset. Method Forty-seven AIS patients who met the inclusion criteria were recruited from Baotou Central Hospital, Department of Neurology from January 2011 to December 2012. The patients had stroke onset within 12 hours and completed MRI scan including diffusion-weighted imaging DWI, apparent diffusion and coefficient ADC FLAIR. Based on MRI findings, patients were divided into, three groups:0~180 min, 180~360 min and 360~720 min groups. Signal strength values of the DWI、FLAIR and ADC in ipsi?lateral and contralateral sides were measured. Result There was a significant difference in the FLAIR signal strength among these three groups.The FLAIR signal strength was significantly lower in 0~180 min and 180~360 min groups than in 360-720 min. FLAIR positive rate was 16.7%, 62.5%, and 70.6% in 0~180 min, 180~360 min and 360~729 min groups, respectively. Conclusion FLAIR positive rate gradually increases as the onset prolongs. Thus, lower FLAIR posi?tive rate indicates shorter onset time of AIS, which can be used to assist acute intravenous thrombolytic therapy.