Abstract TP164: Significance of the Thrombus Component as a Predictor for Malignant Middle Cerebral Artery Infarction

Abstract

Background and Purpose— Malignant middle cerebral artery (MCA) infarction is one of the most devastating forms of ischemic stroke, and identification of predictors of a malignant course of the MCA or internal carotid artery (ICA) infarction is exceedingly important. Here, we investigated whether thrombus component defined with MR imaging could predict malignant changes in the acute stage of the cerebral infarction. Methods— We retrospectively analyzed 468 consecutive patients with cerebral infarction in our institute from 2007 to 2011. In all the patients, initial MR imaging including T2 star (T2*), diffusion weighted imaging (DWI), fluid-attenuated inversion recovery (FLAIR) and MR angiography were performed and susceptibility vessel sign (SVS) on T2* was evaluated in relation to the brain swelling on CT 24 hours after the initial imaging. Correlation of the thrombus component between MRI and CT was also evaluated. Results— One hundred and twelve patients showed MCA main trunk or carotid T occlusion. Among them, 38 patients were t-PA failed or did not undergo endovascular treatment. Twenty eight patients had ICA occlusion and 10 patients had MCA main trunk occlusion. SVS was apparent in 17 (45%) patients, and there was no significant difference between SVS positive and SVS negative group in age (75.6 vs. 72.3 years old), time to arrival (84.4 vs. 106.9 min) and NIH stroke scale (19.5 vs. 18.7). On the other hand, DWI area was significantly larger in SVS positive group (189.3 vs. 107.6 ml). DWI area was also significantly correlated with brain swelling 24 hour later regardless of SVS. Most SVS positive patients showed MCA dense sign on CT performed 24 hours later (85.7% vs. 29.4%). Conclusions— Susceptibility vessel sign on MRI, which suggests RBC rich thrombus, indicates early maturation of the infarct in the MCA area, but could not predict following malignant change.