Significance of Development and Reversion of Collaterals on MRI in Early Neurologic Improvement and Long-Term Functional Outcome after Intravenous Thrombolysis for Ischemic Stroke

AJNR Am J Neuroradiol. 2015 Oct;36(10):1839-45. doi: 10.3174/ajnr.A4384. Epub 2015 Jul 23.


Background and purpose: Predicting response to rtPA is essential in the era of endovascular therapy for stroke. The purpose of this study was to elucidate prognostic factors of early neurologic improvement and long-term outcome with respect to the development and reversion of leptomeningeal collaterals in recanalization therapy after acute ischemic stroke.

Materials and methods: We analyzed consecutive patients with proximal MCA occlusion treated with rtPA from 2007 to 2012 at 2 hospital stroke centers. All patients routinely underwent brain MR imaging before rtPA. To assess the reversion of collateral signs, we included patients who underwent follow-up MR imaging. We assessed the development and reversion of collaterals by using a combination of 2 MR imaging collateral markers, the hyperintense vessel sign and the posterior cerebral artery laterality sign. Early neurologic improvement was defined as a decrease in the NIHSS score of ≥10 or a score of ≤2 at 24 hours of treatment.

Results: Early neurologic improvement was observed in 22 of 48 eligible patients. The development of collaterals at arrival (15/22 versus 9/26, P = .042) was significantly associated with early neurologic improvement. Multivariate analysis adjusting for other variables showed that the development of collaterals at arrival (OR, 4.82; 95% CI, 1.34-19.98; P = .015) was independently associated with early neurologic improvement. Reversion of collaterals was significantly associated with successful recanalization (P < .001), and multivariate analysis showed that the reversion of collaterals was an independent prognostic factor of long-term functional outcome (OR, 5.07; 95% CI, 1.38-22.09; P = .013).

Conclusions: Our results indicate that the development of leptomeningeal collaterals plays a crucial role in achieving early neurologic improvement, and reversion of collaterals predicts a favorable outcome via arterial recanalization after rtPA treatment for acute stroke.

MeSH terms

  • Aged
  • Aged, 80 and over
  • Brain / blood supply*
  • Collateral Circulation / drug effects*
  • Female
  • Follow-Up Studies
  • Humans
  • Infarction, Middle Cerebral Artery / drug therapy*
  • Infarction, Middle Cerebral Artery / physiopathology*
  • Magnetic Resonance Imaging / methods*
  • Male
  • Middle Aged
  • Neurologic Examination / drug effects
  • Thrombolytic Therapy / methods*
  • Tissue Plasminogen Activator / therapeutic use
  • Treatment Outcome


  • Tissue Plasminogen Activator