Magnitude Signal Intensity And Phase Value Of Susceptibility Vessel Sign Predict Response To Intravenous Thrombolysis In Acute Cerebral Infarction

ObjectiveTo assess the predictive value of susceptibility vessel sign(SVS) and its magnitude signal intensity and phase value for recanalization after Intravenous Recombinant Tissue Plasminogen Activator(IV rt-PA).MethodsWe retrospectively studied28acute cerebral infarction patients with internal carotid artery(ICA) or middle cerebral artery(MCA) occlusion treated with IV rt-PA. According to baseline ESWAN, we divided patients into two groups:with SVS(SVS(+)) and without SVS(SVS(-)), and compared clinical and imaging characteristics of the two groups.ROI containing SVS/M1SVS was drew on magnitude images which combined8echo images, then superimpose it onto other images of the same slice automatically, mean magnitude signal intensity(on images with echo time(TE)=5ms and40ms) and mean phase value of corresponding SVS/M1SVS ROI was measured. Recanalization within24h after treatment was assessed by the Thrombolysis In Myocardial Infarction(TIMI) on Magnetic resonance angiography(MRA).Correlation between magnitude/phase value of SVS/M1SVS and TIMI grade was calculated. The P value for significance was set at0.05.ResultsThere was no significant difference in clinical or imaging characteristics between SVS(+) and SVS(-), except baseline NIHSS and frequency of "good improvement"1day after thrombolysis.In the group of SVS(+)(n=16), there was negative correlation between magnitude signal intensity of SVS (TE=5ms)and TIMI grade (rs=-0.652,P=0.006), patients with TIMI>2demonstrated lower signal intensity compared with patients with TIMI<2(P=0.042). In the subgroup with M1SVS (n=14),there was negative correlation between magnitude signal intensity of M1SVS (TE=5ms) and TIMI grade(rs=-0.636,P=0.015), positive correlation between phase value of Ml SVS and TIMI grade (rs=0.622,P=0.017), patients with TIMI>2demonstrated higher phase value of SVS compared with patients with TIMI<2(P=0.024).ConclusionMagnitude signal intensity and phase value of SVS/M1SVS before treatment may help to predict the response to intravenous thrombolytic therapy in acute cerebral infarction.