title: Post-carotid endarterectomy changes in cerebral glucose metabolism on (18)F-fluorodeoxyglucose positron emission tomography associated with postoperative improvement or impairment in cognitive function.
abstract: OBJECTIVE
  Cognitive function is often improved or impaired after carotid endarterectomy (CEA) for patients with cerebral hemodynamic impairment. Cerebral glucose metabolism measured using positron emission tomography (PET) with (18)F-fluorodeoxyglucose (FDG) correlates with cognitive function in patients with neurodegenerative diseases. The present study aimed to determine whether postoperative changes in cerebral glucose metabolism are associated with cognitive changes after CEA.
  
  
  METHODS
  In patients who were scheduled to undergo CEA for ipsilateral internal carotid artery (ICA) stenosis (≥ 70% narrowing), cerebral blood flow (CBF) and cerebrovascular reactivity (CVR) to acetazolamide were assessed preoperatively using brain perfusion single-photon emission computed tomography (SPECT). CBF measurement using SPECT was also performed immediately after CEA. For patients with reduced preoperative CVR to acetazolamide in the cerebral hemisphere ipsilateral to surgery, cerebral glucose metabolism was assessed using FDG-PET before surgery and 3 months after surgery and was analyzed using 3D stereotactic surface projection. Neuropsychological testing was also performed preoperatively and 3 months postoperatively.
  
  
  RESULTS
  Twenty-two patients with reduced preoperative CVR to acetazolamide successfully underwent FDG-PET studies and neuropsychological testing before and after CEA. Seven, 9, and 6 patients were defined as showing improved, unchanged, and impaired postoperative cognition, respectively, based on the neuropsychological assessments. The cortical area with increased postoperative glucose metabolism was greater in patients with improved postoperative cognition than in those with unchanged (p < 0.001) or impaired (p < 0.001) postoperative cognition. The cortical area with decreased postoperative glucose metabolism was greater in patients with impaired postoperative cognition than in those with improved (p < 0.001) or unchanged (p < 0.001) postoperative cognition. All 7 patients with improved cognition exhibited postoperative hemispheric increases in glucose metabolism, while 5 of the 6 patients with impaired cognition exhibited postoperative hemispheric decreases in glucose metabolism. Brain perfusion SPECT revealed that the latter 6 patients experienced postoperative cerebral hyperperfusion, and 2 of the 6 patients exhibited cerebral hyperperfusion syndrome. The cortical area with decreased postoperative glucose metabolism in these 2 patients was greater than that in other patients.
  
  
  CONCLUSIONS
  Postoperative changes in cerebral glucose metabolism, as measured using FDG-PET, are associated with cognitive improvement and impairment after CEA.
authors.affiliation: Department of Neurosurgery.|Cyclotron Research Center, School of Medicine, Iwate Medical University, Iwate, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Yoshida
authors.affiliation: Department of Neurosurgery.|Cyclotron Research Center, School of Medicine, Iwate Medical University, Iwate, Japan.
authors.forename: Kuniaki
authors.initials: K
authors.lastname: Ogasawara
authors.affiliation: Department of Neurosurgery.|Cyclotron Research Center, School of Medicine, Iwate Medical University, Iwate, Japan.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Saura
authors.affiliation: Department of Neurosurgery.|Cyclotron Research Center, School of Medicine, Iwate Medical University, Iwate, Japan.
authors.forename: Hideo
authors.initials: H
authors.lastname: Saito
authors.affiliation: Department of Neurosurgery.|Cyclotron Research Center, School of Medicine, Iwate Medical University, Iwate, Japan.
authors.forename: Masakazu
authors.initials: M
authors.lastname: Kobayashi
authors.affiliation: Department of Neurosurgery.
authors.forename: Kenji
authors.initials: K
authors.lastname: Yoshida
authors.affiliation: Cyclotron Research Center, School of Medicine, Iwate Medical University, Iwate, Japan.
authors.forename: Kazunori
authors.initials: K
authors.lastname: Terasaki
authors.affiliation: Department of Neurosurgery.
authors.forename: Shunrou
authors.initials: S
authors.lastname: Fujiwara
authors.affiliation: Department of Neurosurgery.|Cyclotron Research Center, School of Medicine, Iwate Medical University, Iwate, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Ogawa
mesh_terms: D000086:Acetazolamide; D000368:Aged; D001921:Brain / Q000378:metabolism*; D016893:Carotid Stenosis / Q000378:metabolism / Q000523:psychology* / Q000601:surgery*; D002560:Cerebrovascular Circulation; D003072:Cognition Disorders / Q000209:etiology / Q000378:metabolism* / Q000517:prevention & control; D015331:Cohort Studies; D016894:Endarterectomy, Carotid; D005260:Female; D019788:Fluorodeoxyglucose F18; D005947:Glucose / Q000378:metabolism*; D006801:Humans; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography; D019275:Radiopharmaceuticals; D015899:Tomography, Emission-Computed, Single-Photon
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18; D005947:Glucose; D000086:Acetazolamide
keywords: 123I-IMP = N-isopropyl-p-[123I]-iodoamphetamine; 18F-fluorodeoxyglucose; AI = asymmetry index; CBF = cerebral blood flow; CCH = crossed cerebellar hypoperfusion; CEA = carotid endarterectomy; CVR = cerebrovascular reactivity; FDG = 18F-fluorodeoxyglucose; ICA = internal carotid artery; MCA = middle cerebral artery; PET = positron emission tomography; ROI = region of interest; Rey = Rey-Osterrieth Complex Figure test; SPECT = single-photon emission computed tomography; WAIS-R = Wechsler Adult Intelligence Scale-Revised; WMS = Wechsler Memory Scale; carotid endarterectomy; cerebral metabolism; cognition; positron emission tomography; vascular disorders