Permeability surface area product analysis in malignant brain edema prediction - A pilot study.

Background And Purpose: Using an extended CT perfusion acquisition (150s), we sought to determine the association between perfusion parameters and malignant edema after ischemic stroke.

Methods: Patients (from prospective study PROVE-IT, NCT02184936) with terminal internal carotid artery±proximal middle cerebral occlusion were involved. CTA was assessed for clot location and status of leptomeningeal collaterals. The following CTP parameters were calculated within the ischemic territory and contralaterally: permeability surface area product (PS), cerebral blood flow (CBF) and cerebral blood volume (CBV). PS was calculated using the adiabatic approximation to the Johnson and Wilson model. Outcome was evaluated by midline shift and infarction volume on follow-up imaging.

Results: Of 200 patients enrolled, 7 patients (3.5%) had midline shift≥5mm (2 excluded for poor-quality scans). Five patients with midline shift and 5 matched controls were analysed. There was no significant difference in mean PS, CBF and CBV within the ischemic territory between the two groups. A CBV threshold of 1.7ml/100g had the highest AUC=0.72, 95% CI=0.54-0.90 for early midline shift prediction, sensitivity and specificity were 0.83 and 0.67 respectively.

Conclusion: Our preliminary results did not show significant differences in permeability surface area analysis if analysed for complete ischemic region. CBV parameter had the highest accuracy and there was a trend for the mean PS values for midline shift prediction.