Prediction of cerebral hyperperfusion syndrome after carotid stenting: a cerebral perfusion computed tomography study.

Purpose: The objective of this study was to evaluate the role of cerebral perfusion computed tomography (CT) in predicting cerebral hyperperfusion syndrome (CHS) after carotid stenting. Materials and Methods: This study was approved by the institutional review board, and written informed consent was obtained from all patients. Fifty-five consecutive symptomatic patients with greater than or equal to 70% of cervical carotid artery stenosis who underwent carotid stenting from March 2001 to December 2003 were recruited. Age, sex, stenting side, and degree of cervical carotid stenosis at the stenting and contralateral sides were recorded. Cerebral perfusion CT was performed I day before stenting. Absolute values of the cerebral blood volume, mean transit time, and cerebral blood flow were calculated. Relative values based on the comparison between ipsilateral and contralateral hemispheres, that is, relative cerebral blood volume (ipsilateral-to-contralateral ratio), relative cerebral blood flow (ipsilateral-to-contralateral ratio), and absolute difference in mean transit time (dMTT), were derived. The association between occurrence of CHS and parameters of cerebral perfusion CT,,vas investigated by the Mann-Whitney U test. Results: Three (5%) of 55 patients had CHS after carotid stenting. The only significant factor related to the occurrence of CHS was dMTT (P = 0.003). A dMTT value of 3 seconds was considered as a cutoff value to distinguish between the occurrence and absence of CHS. The other clinical or cerebral perfusion CT parameters had no significant correlation with the occurrence of CHS. Conclusion: Our findings suggest that patients with a prolonged dMTT of more than 3 seconds should be closely monitored for evidence of hyperperfusion after undergoing carotid stenting.