Abstract 2427: Significance of Susceptibility Vessel Sign on T2 Star Weighted-images to Predict Clinical Outcome following Emergency Endovascular Treatment in Patients with Probable Acute Embolic Basilar Artery Occlusion

Abstract

Purpose The purpose of our retrospective study is to investigate whether or not susceptibility vessel sign of the basilar artery (SVS-BA) on T2*-weighted gradient echo images at 1.5T can predict clinical outcome after emergency endovascular treatment (EET) in patients where MRA suggests the embolic acute BA occlusion. Materials and Methods Included for retrospective analysis were patients as follows, (1) study period was from November 2005 to December 2010, (2) who were admitted to our institution within 8 hours from stroke onset, (3) who underwent emergency MR imaging including DWI, T2*WI, MRA at 1.5T and symptomatic and embolic acute BAO was diagnosed by MRA, (4) whose NIHSS score on admission was 10 or more, and (5) who underwent EET. Excluded were patients (1) in whom DWIs showed extensive high signal intensity area in pons or cerebelli, (2) who had contraindications for EET. They were divided into two groups according to presence (group P) or absence (group A) of SVS-BA on T2*WI. The relationships between the presence of BA-SVS and patients’ baseline characteristics on admission (age, gender), onset to admission time (OTA time), onset to treatment time (OTT time), NIHSS on admission (NIHadm), NIHSS on the 7th day (NIH7th), modified Rankin Scale at 3 months (3M-mRS) and estimated lengths of BAO on emergency MRA (eMRA) were investigated. Estimated lengths of BAO were graded according to eMRA as follows: grade 4, no occlusion; grade 3, occluded distal AICA; grade 2, occluded distal union; grade 1: not visualized. TIMI grades 2 and 3 were defined as successful recanalization. Results During the study periods, 17 patients were included for analysis. Successful recanalization was achieved in 11 patients (65%). In P (n=8) and A (n=9) groups, there were no significant differences statistically in age (mean; 73.6±15.2 and 68.1±14.0 years), man (%) (88 and 89), OTA time (median; 0.8 and 1.7 hrs), OTT time (median; 4.2 and 3.5 hrs), and NIHadm (median; 27 and 16). There were significant differences between two groups in BAO grade (median; 1.5 and 3), successful recanalization rate (%) (38 and 89), NIH7th (median; 35 and 8), 3M-mRS (median; 5.5 and 3) (p<0.05), respectively. Conclusion Clinical outcome following emergency endovascular treatment for probable acute embolic basilar artery occlusion was better in patients without SVS-BA on T2*WI than with SVS-BA. The SVS-BA on T2*WI seems to be a significant predictor for achieving less recanalization immediately after EET.