Abstract TP541: CT Angiography Leptomeningeal Collateral Assessment for Vasospasm in Patients With Aneurysmal Subarachnoid Hemorrhage

Abstract

Introduction: Although leptomeningeal collaterals in acute large vessel occlusion have been well studied with respect to core infarct volume and risk of hemorrhagic conversion, their association with vasospasm in the setting of subarachnoid hemorrhage is less clear. Our purpose is to investigate the utility of leptomeningeal collateral scoring on CTA of patients presenting with aneurysmal subarachnoid hemorrhage (aSAH). Methods: IRB-approved retrospective review of 122 consecutive patients with angiographic vasospasm after surgical or endovascular repair of ruptured intracranial aneurysm. A 5-point grading scale was adapted from Christoforidis et al. to compare leptomeningeal collateral scores on CTA with digital subtraction agiography (DSA) at presentation. An independent chart review was performed to correlate imaging with clinical markers of symptomatic vasospasm and delayed cerebral ischemia. Results: Of the 122 initial patients with vasospasm, 16 demonstrated unilateral high-grade M1 stenosis in the absence of a second ipsilateral large vessel stenosis, 11 of which (68.8%) developed cerebral infarction secondary to vasospasm. Leptomeningeal collateral scoring on CTA at presentation agreed with DSA scores in half of patients (n=8), underestimated collaterals by 1 point in 7 patients, and overestimated their presence by 1 point in a single case. Conclusion: Characterization of leptomeningeal collaterals in patients with aSAH may better predict subsequent vasospasm and cerebral ischemia. Our initial findings in cases of isolated severe M1 vasospasm highlight the potential value of collateral scoring on CTA at presentation. Collateral scoring on CTA correlates with DSA in half of cases, however further work is indicated to elucidate the technical factors contributing to 1-point underestimation in the other half cases. Christoforidis, G.A., et al., Predictors of hemorrhage following intra-arterial thrombolysis for acute ischemic stroke: the role of pial collateral formation. AJNR Am J Neuroradiol, 2009. 30 (1): p. 165-70.