title: M1 susceptibility vessel sign on T2* as a strong predictor for no early recanalization after IV-t-PA in acute ischemic stroke.
abstract: OBJECTIVE
  In acute stroke patients treated with intravenous tissue plasminogen activator (t-PA), early recanalization of occluded arteries can improve the clinical outcome. The magnetic susceptibility effect of deoxygenated hemoglobin in red thrombi can present as hypointense signals on T2*-weighted gradient echo imaging. We investigated whether the gradient echo imaging M1 susceptibility vessel sign (M1 SVS) can predict no early recanalization after t-PA infusion.
  
  
  METHODS
  Patients with internal carotid artery and M1 occlusion were prospectively studied. MRI studies, including DWI, T2*, and MRA, were performed before and within 30 minutes and 24 hours after t-PA infusion. The NIHSS score was obtained before and 7 days after t-PA administration. The relationship between the presence of the M1 SVS and no early recanalization and patient outcome was examined.
  
  
  RESULTS
  A total of 48 patients (29 men; mean age, 74.6+/-11.2 years) were enrolled. M1 SVS was present in 13 (27.1%) patients and absent in 35 (72.9%) patients. There were no significant differences in clinical characteristics between the 2 groups. Follow-up MRA within 30 minutes after t-PA infusion revealed that 20 (57.1%) of the 35 patients without the M1 SVS had early recanalization, but that none of the 13 patients with the M1 SVS had early recanalization (P=0.0002). Seven days after t-PA infusion, dramatic improvement was more frequently observed in patients without the M1 SVS (51.4%) than in those with the M1 SVS (0%, P=0.0007).
  
  
  CONCLUSIONS
  The M1 SVS on T2* appears to be a strong predictor for no early recanalization after t-PA therapy.
authors: Kazumi
authors: K
authors: Kimura
authors: Yasuyuki
authors: Y
authors: Iguchi
authors: Kensaku
authors: K
authors: Shibazaki
authors: Masao
authors: M
authors: Watanabe
authors: Takeshi
authors: T
authors: Iwanaga
authors: Junya
authors: J
authors: Aoki
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002545:Brain Ischemia / Q000000981:diagnostic imaging* / Q000188:drug therapy*; D005260:Female; D005343:Fibrinolytic Agents / Q000008:administration & dosage*; D006801:Humans; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies; D011859:Radiography; D020521:Stroke / Q000000981:diagnostic imaging* / Q000188:drug therapy*; D010959:Tissue Plasminogen Activator / Q000008:administration & dosage*
chemical_list: D005343:Fibrinolytic Agents; D010959:Tissue Plasminogen Activator