CT Perfusion Changes in Ischemic Stroke Due to Isolated Internal Carotid Artery Occlusions: From Severity Assessment to Therapy

Introduction: acute ischemic stroke (AIS) due to isolated extra-cranial internal carotid artery occlusion (i-ICAO) is clinically heterogenous, ranging from mild symptomatic cases to fatal hemispheric involvement. This depends on several factors, such as changes in intracranial hemodynamics and collateral pathways. There are no clear recommendations on the best treatment to adopt between endovascular therapy (EVT) and best medical treatment (BMT). We hypothesized that a patient-specific characterization of the extent of the affected brain parenchyma through the perfusion CT (PCT) may provide more accurate information on stroke severity and can help guide therapeutic management. Materials: from January 2020 to February 2025, we retrospectively examined 698 patients that were consecutively admitted for confirmed AIS and identified 25 patients with an AIS resulting from i-ICAO. Clinical, neuroimaging and procedural data were analyzed. Results: 17 out of 25 patients underwent EVT and 8/25 were treated with BMT. As compared with BMT group, patients undergoing EVT showed higher NIHSS score at hospital admission (14.1 ± 5.6 Vs 6.2 ± 4.8 respectively, p<0.05), wider mean penumbra volume (193.8 ± 147.1 ml Vs 30.0 ± 23.0 ml respectively, p<0.05) and a larger core volume (7.9 ± 8.6 ml Vs 0.9 ± 1.6 ml respectively, p<0.05). No difference in functional status at hospital discharge was showed between groups. ROC analysis showed that penumbra volume was a better predictor of EVT than NIHSS at hospital admission alone (AUC 0.94 and 0.85 respectively). Conclusions: in AIS due to i-ICAO, our findings showed that EVT was performed in subjects presenting with a more severe stroke; furthermore, the extent of the penumbral volume appears to better predict subjects referred for EVT. In conclusion, our data suggest that using PCT data to characterize the effects that i-ICAO exerts on intracranial hemodynamics could aid in the therapeutic strategy.