title: Postoperative changes in cerebral metabolites associated with cognitive improvement and impairment after carotid endarterectomy: a 3T proton MR spectroscopy study.
abstract: OBJECTIVE
  Cognitive function can improve or decline after carotid endarterectomy. Proton MR spectroscopy can be used evaluate cerebral metabolites, such as N-acetylaspartate, choline, and creatine, in vivo. The purpose of the present study was to determine whether postoperative changes in cerebral metabolites measured by using 3T proton MR spectroscopy were associated with changes in cognitive function after CEA.
  
  
  METHODS
  In 100 patients undergoing CEA for ipsilateral cervical internal carotid artery stenosis (≥70%), brain proton MR spectroscopy was performed before and after surgery. NAA/Cr and Cho/Cr ratios were measured in regions of interest placed in the centrum semiovale of both cerebral hemispheres. Neuropsychological testing was also performed preoperatively and 1 month postoperatively. Multivariate statistical analysis of factors related to postoperatively changed cognition was performed, and odds ratios with 95% confidence intervals were calculated.
  
  
  RESULTS
  On the basis of the neuropsychological assessments, 10 (10%), 80 (80%), and 10 (10%) patients were defined as having postoperatively improved, unchanged, and impaired cognition, respectively. A positive and high ΔNAA/Cr ratio (postoperative value-preoperative value) in the cerebral hemisphere ipsilateral to the operative site was significantly associated with postoperatively improved cognition (95% CI, 13.3-21.3; P = .0016). Negative and high absolute values of the ΔNAA/Cr ratio (95% CI, 0.018-0.101; P = .0039) and ΔCho/Cr ratio (95% CI, 0.042-0.135; P = .0046) in the ipsilateral cerebral hemisphere were significantly associated with postoperatively impaired cognition.
  
  
  CONCLUSIONS
  Postoperative changes in cerebral metabolites measured by using proton MR spectroscopy were associated with changes in cognitive function after CEA.
authors.affiliation: Department of Neurosurgery, Iwate Medical University, Uchimaru, 19-1, Morioka 020-8505, Japan. kuogasa@iwate-med.ac.jp
authors.forename: H
authors.initials: H
authors.lastname: Saito
authors.forename: K
authors.initials: K
authors.lastname: Ogasawara
authors.forename: H
authors.initials: H
authors.lastname: Nishimoto
authors.forename: Y
authors.initials: Y
authors.lastname: Yoshioka
authors.forename: T
authors.initials: T
authors.lastname: Murakami
authors.forename: S
authors.initials: S
authors.lastname: Fujiwara
authors.forename: M
authors.initials: M
authors.lastname: Sasaki
authors.forename: M
authors.initials: M
authors.lastname: Kobayashi
authors.forename: K
authors.initials: K
authors.lastname: Yoshida
authors.forename: Y
authors.initials: Y
authors.lastname: Kubo
authors.forename: T
authors.initials: T
authors.lastname: Beppu
authors.forename: A
authors.initials: A
authors.lastname: Ogawa
mesh_terms: D000368:Aged; D001921:Brain / Q000378:metabolism*; D016893:Carotid Stenosis / Q000453:epidemiology / Q000378:metabolism* / Q000601:surgery*; D003072:Cognition Disorders / Q000453:epidemiology / Q000378:metabolism*; D015897:Comorbidity; D016894:Endarterectomy, Carotid / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D007564:Japan / Q000453:epidemiology; D009682:Magnetic Resonance Spectroscopy / Q000379:methods / Q000706:statistics & numerical data*; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000453:epidemiology / Q000378:metabolism*; D015995:Prevalence; D011522:Protons; D015203:Reproducibility of Results; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D016896:Treatment Outcome
chemical_list: D011522:Protons