The Ghost Penumbra Pattern in Acute Ischemic Stroke: Characterization and Prognostic Significance

ABSTRACT Background and Purpose We studied the so‐called ghost penumbra pattern (GPP), characterized by an underestimation of ischemic core volume on computed tomography perfusion (CTP) as compared with noncontrast CT (NCCT). We aimed to describe its frequency, to characterize the baseline factors associated with its presence, and to investigate its impact on clinical and radiological outcomes in acute ischemic stroke (AIS) patients treated with endovascular therapy (EVT). Methods A consecutive series of AIS patients with proximal anterior circulation large vessel occlusion (LVO) treated with EVT and achieving successful reperfusion were included. All underwent NCCT, multiphase CT angiography (CTA), and CTP, which were analyzed with RAPID software. Ischemic core volumes were compared between CT and CTP. GPP was defined by a CT core/CTP core ratio >1.5. Collateral status and thrombus migration were assessed. Parenchymal hematoma (PH) and hypodensity volume were measured at 24 h. Functional outcome was evaluated at 90 days using the modified Rankin Scale. Results From June 2020 to December 2021, a total of 173 AIS patients were included in the study (mean age was 73; 52% women; median National Institutes of Health Stroke Scale [NIHSS] 16). GPP was detected in 100 (58%) patients. Good collateral circulation (OR 2.8 [1.5–5.4]; p = 0.001) and lower NIHSS (OR 0.9 [0.8–0.9]; p = 0.02) were independently associated with GPP. The GPP predicted a lower risk of PH (OR 0.43 [0.19–0.97]; p = 0.04). Conclusion GPP was observed in about half of the included AIS patients and was associated with better collateral circulation and thrombus migration. Endovascular reperfusion in this group was safe.