Edinburgh Imaging

MSc projects 2021 004

Magnetic resonance imaging methods in the assessment of collateral circulation pre thrombectomy and its association with outcome : a systematic review.

  • Aims: This study aims to review the various magnetic resonance imaging (MRI) methods that have been proposed to assess the collateral status (CS) in acute ischemic stroke (AIS) patients treated with endovascular thrombectomy (EVT) and its impact on functional independence.
  • Methods: I systematically reviewed Ovid EMBASE and Ovid MEDLINE from their foundation dates to March 2021 and manually searched reference lists to extract studies that evaluated CS with MRI employing a predefined criteria. Sensitivity and subgroup analyses were performed and the extracted data were presented as relative risk (RR) and 95% confidence interval (CI) to express the relationship between dichotomized pre-treatment CS (good and poor) and functional independence (modified Rankin score (mRs ≤ 2)) at 90-days.
  • Results: A total of 21 studies (1535 patients) qualified for the qualitative synthesis and 7 studies (623 patients) for the metanalysis. Good pre-thrombectomy collaterals significantly correlated with favourable outcome at 90-days (RR 1.75, 95% CI [1.33,2.31], P< 0.0001), in AIS patients. Opting out studies did not change the overall effect estimate and there was no evidence of statistical heterogeneity (I2=11%) with evidence of publication bias.
  • Conclusion: good pre-treatment CS is associated with higher rates of functional independence at 90 days in AIS patients treated with EVT. The proposed MRI sequences, postprocessing techniques, cut-offs and grading scales varied considerably, and are relatively novel. For that, prior to implementing CS assessment in the routine MR stroke protocol, methods should be well validated with a special focus on simple angiographic methods.
Project type:
  • Systematic review
Imaging keywords:
Application / disease keywords:
  • Acute ischemic stroke (AIS)
  • Endovascular thrombectomy (EVT)
  • 20-21