The Hyperacute Phase of Cerebral Infarction in a Swine Model Investigated with Cone-Beam CT Perfusion Imaging

In the clinical practice, patients hospitalized within 60 minutes from onset of stroke are rarely seen. This study investigated this phase in a swine middle cerebral artery (MCA) occlusion model using cone-beam CT perfusion imaging. Seven swine underwent MCA occlusion by electrocoagulation followed by cone-beam CT perfusion imaging every 10 minutes for 100 minutes. Using prototype software, cerebral blood flow (CBF), cerebral blood volume (CBV), and mean transit time (MTT) images were obtained. Regions of interest (ROI) were placed in the infarcted and contralateral hemispheres to calculate relative values. The relative CBF decreased from 1 (at time zero, before MCA occlusion) to 0.44 (p = 0.01 at 10 min), the relative CBV initially decreased from 1 to 0.54 (p = 0.02 at 10 min), followed by transient recovery, and the relative MTT gradually increased from 1 to 2.32 (p= 0.003 at 50 min). After approximately 50 minutes, the stroke appeared complete (relative values: CBF = 0.19, CBV = 0.52, and MTT = 3.30), with an estimated slope of zero for all parameters. The infarcted area was confirmed by pathology. Our results indicate that perfusion parameters in the hyperacute stroke phase can be investigated in continuity with cone-beam CT perfusion imaging in a swine stroke model. Compensatory mechanisms of CBV to maintain CBF started immediately after occlusion and MTT increased but could not counteract infarct development.