Quantitative Evaluation of Ischemic Core Volume in GE's CT Perfusion Imaging Analysis Software and Its Relationship to Alberta Stroke Program Early CT Score.

Objective: Computed tomography (CT) and magnetic resonance imaging of cerebral perfusion are useful in determining the indication of mechanical thrombectomy (MT) for acute ischemic stroke. RAPID (iSchemaView, Menlo Park, CA, USA) is the most common software for analyzing brain perfusion images worldwide, but various other software are also available. The optimal threshold value for each software is different, and each has its characteristics. This study investigated the relationship between the quantitative evaluation of ischemic core volume (ICV) and the Alberta Stroke Program Early CT Score (ASPECTS) using CT Perfusion 4D (GE Healthcare Inc., Milwaukee, WI, USA), a software used in our hospital.

Methods: Among patients who underwent MT between April 2015 and February 2023, those with modified Rankin Scale: 0-2, obstruction by embolic mechanism, and thrombolysis in cerebral infarction: 2b or higher were selected retrospectively. Patients with middle cerebral artery M1 segment (M1) and internal carotid artery (ICA) occlusions (90 and 46 patients) were included. We quantitatively analyzed ICV at relative cerebral blood flow (rCBF) <20% and cerebral blood volume (CBV) <1 mL/100 g and evaluated the relationship with ASPECTS scores in 3 groups: M1 + ICA, M1, and ICA occlusion groups.

Results: The median ICV was rCBF <20%: 44.7 cm³ and CBV <1 mL/100 g: 34.6 cm³, and there was no statistically significant difference between the 2 groups (p = 0.23). There was a negative correlation between ICV and ASPECTS scores in each occlusion group in all groups.

Conclusion: The quantitative evaluation of ICV at rCBF <20% and CBV <1 mL/100 g was negatively correlated with the ASPECTS score in GE's CT Perfusion imaging analysis software.