Abstract WP175: The Significance of Perfusion Computed Tomography in the Prediction of Hyperperfusion After Carotid Endarterectomy

Abstract

Purpose: Cerebral hyperperfusion syndrome (CHS) is a rare devastating complication associated with hyperperfusion after carotid endarterectomy. Single photon emission computed tomography (SPECT) is usually used with acetazolamide challenge to measure the cerebrovascular reserve (CVR), and a decreased CVR is indicative of a high risk of post CEA hyperperfusion. However, acetazolamide administration can rarely cause serious adverse effects, and thus, alternative methods may be required. Perfusion computed tomography (PCT) is a rapid, more accessible modality, which can be acquired with CT angiography. PCT seems to be useful as a screening tool in identifying groups at high-risk of hyperperfusion, but its usefulness has not sufficiently investigated. Our purpose was to clarify the relationship between hyperperfusion and the preoperative PCT parameters of cerebral blood flow (CBF), cerebral blood volume (CBV), and mean transit time (MTT). Method: We included patients who underwent carotid endarterectomy in our hospital from 2014 December to 2018 April. PCT was obtained preoperatively and on postoperative day 1. Hyperperfusion is defined as a postoperative CBF of the middle cerebral artery area which has increased twice that of the preoperative value. CHS was defined as any symptom and imaging findings related with hyperperfusion, which include headache, seizure, neurological dysfunction, and any intracranial hemorrhage in the related area. Preoperative CBF, CBV, MTT and other patient characteristics are statistically analyzed between a hyperperfusion group and non-hyperperfusion group. Result: There are 73 patients who underwent CEA during the study period, and hyperperfusion was observed in 5 cases, from which 2 were considered as CHS. In the hyperperfusion group, the preoperative CBF was significantly lower (p=0.0008), and the CBV and MTT significantly higher (p=0.0196, p=0.0002). ROC analysis showed that the PCT parameters with the maximal area under the receiver-operating characteristic curve for hyperperfusion was preoperative MTT with an optimal threshold at 8.0 seconds (sensitivity 100%, specificity 100%). Conclusion: Patient with prolonged preoperative MTT tend to develop hyperperfusion, which is related to CHS.