Collateral Supply Patterns in Patients with Internal Carotid Stenosis & Occlusion Investigated with Territorial & Reactivity Arterial Spin Labeling

Nolan S. Hartkamp¹, Jeroen Hendrikse¹, Reinoud P.H. Bokkers¹, Matthias J.P. van Osch², Esben T. Petersen¹

Collateral circulation plays a vital role in patients with steno-occlusive disease, in particular for predicting outcome. By combining territorial ASL which measurement collateral flow with ASL before and after an acetazolamide challenge, we have classified the supply patterns and their respective auto regulative capacity in ICA stenosis and occlusion patients. In particular, we categorize the collateral perfusion either as primary, i.e. via the circle-of-willis or secondary as collateral flow via the ophthalmic artery or leptomeningeal collaterals. Secondary collaterals showed significantly worse autoregulation than primary collaterals and contra-lateral hemisphere, in line with the fact that leptomeningeal signals higher stroke recurrence.