Abstract 13: Asymmetry of Deep Medullary Veins in Susceptibility Weighted Imaging is associated with Poor Collaterals in Patients with Acute Ischemic Stroke

Abstract

Background: Susceptibility Weighted Imaging (SWI) is a high spatial resolution of MR imaging technique showing magnetic inhomogeneity that could demonstrate increased oxygen extraction in ischemic hemisphere. The aim of this study was to investigate whether the asymmetry of deep medullary veins (DMVs) on SWI could indicate the poor collateral flow, which results in the hemodynamic derangement in acute ischemic stroke. Methods: Consecutive 132 patients with acute middle cerebral artery infarction within 6 hours from symptom onset were included. The DMVs of ipsilesional region of interests (ROIs) and contralateral ROIs were evaluated; score 0: no DMVs, score 1: moderately visibility of DMVs, and score 2: obviously visibility of DMVs. Asymmetry is defined as the difference in the scores of DMVs between both hemispheres. Collateral status on conventional angiography was graded 0 to 4 based on the ASTIN/SIR collateral flows grading system. Poor collateral flow is defined as grade 0-1. Early neurological deterioration was defined as an increase in the NIHSS score by ≥4 points during the first 48 hours after admission. Multivariable logistic regression analysis was used to examine the association between the presence of asymmetry of DMVs and poor collateral flow or clinical outcomes. Results: Of 132 patients, 74 (56.1%) had asymmetry of DMVs. Asymmetry of DMVs was independently associated with the poor collateral status (OR; 42.1, 95% confidential interval 1.99.-89.81, p=0.02) after adjusting confounders. Moreover, patients with asymmetry of DMVs were likely to have more profound infarction growth (OR; 6.01, 95% CI, 1.21-29.88, p=0.03) and results in the early neurological deterioration (OR; 5.49, 95% CI, 1.21-28.57, p=0.03). Conclusion: Asymmetry of DMVs is independently associated with poor collateral status which affects the clinical deterioration in patients with acute middle cerebral artery stroke.