title: The role of perfusion computed tomography in the prediction of cerebral hyperperfusion syndrome.
abstract: BACKGROUND
  Hyperperfusion syndrome (HPS) following carotid angioplasty with stenting (CAS) is associated with significant morbidity and mortality. At present, there are no reliable parameters to predict HPS. The aim of this study was to clarify whether perfusion computed tomography (CT) is a feasible and reliable tool in predicting HPS after CAS.
  
  
  RESULTS
  We performed a retrospective case-control study of 54 patients (11 HPS patients and 43 non-HPS) with unilateral severe stenosis of the carotid artery who underwent CAS. We compared the prevalence of vascular risk factors and perfusion CT parameters including regional cerebral blood volume (rCBV), regional cerebral blood flow (rCBF), and time to peak (TTP) within seven days prior to CAS. Demographic information, risk factors for atherosclerosis, and perfusion CT parameters were evaluated by multivariable logistic regression analysis. The rCBV index was calculated as [(ipsilateral rCBV - contralateral rCBV)/contralateral rCBV], and indices of rCBF and TTP were similarly calculated. We found that eleven patients had HPS, including five with intracranial hemorrhages (ICHs) of whom three died. After a comparison with non-HPS control subjects, independent predictors of HPS included the severity of ipsilateral carotid artery stenosis, 3-hour mean systolic blood pressure (3 h SBP) after CAS, pre-stenting rCBV index >0.15 and TTP index >0.22.
  
  
  CONCLUSIONS
  The combination of severe ipsilateral carotid stenosis, 3 h SBP after CAS, rCBV index and TTP index provides a potential screening tool for predicting HPS in patients with unilateral carotid stenosis receiving CAS. In addition, adequate management of post-stenting blood pressure is the most important treatable factor in preventing HPS in these high risk patients.
authors.affiliation: Stroke Center and Department of Neurology, Chang Gung Memorial Hospital, Linkou Medical Center and College of Medicine, Chang Gung University, Kueishan, Taoyuan, Taiwan.
authors.forename: Chien Hung
authors.initials: CH
authors.lastname: Chang
authors.forename: Ting Yu
authors.initials: TY
authors.lastname: Chang
authors.forename: Yeu Jhy
authors.initials: YJ
authors.lastname: Chang
authors.forename: Kuo Lun
authors.initials: KL
authors.lastname: Huang
authors.forename: Shy Chyi
authors.initials: SC
authors.lastname: Chin
authors.forename: Shan Jin
authors.initials: SJ
authors.lastname: Ryu
authors.forename: Tao Chieh
authors.initials: TC
authors.lastname: Yang
authors.forename: Tsong Hai
authors.initials: TH
authors.lastname: Lee
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D017130:Angioplasty; D016893:Carotid Stenosis / Q000150:complications* / Q000601:surgery; D016022:Case-Control Studies; D002560:Cerebrovascular Circulation; D002561:Cerebrovascular Disorders / Q000175:diagnosis* / Q000209:etiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D055420:Perfusion Imaging; D011183:Postoperative Complications; D012189:Retrospective Studies; D013577:Syndrome; D014057:Tomography, X-Ray Computed