title: Postoperative increase in cerebral white matter fractional anisotropy on diffusion tensor magnetic resonance imaging is associated with cognitive improvement after uncomplicated carotid endarterectomy: tract-based spatial statistics analysis.
abstract: BACKGROUND
  Carotid endarterectomy (CEA) might improve cognitive function. Fractional anisotropy (FA) values in the cerebral white matter derived from diffusion tensor magnetic resonance imaging (DTI) correlate with cognitive function in patients with various central nervous system diseases.
  
  
  OBJECTIVE
  To use tract-based spatial statistics to determine whether postoperative changes of FA values in the cerebral white matter derived from DTI are associated with cognitive improvement after uncomplicated CEA.
  
  
  METHODS
  In 80 patients undergoing CEA for ipsilateral internal carotid artery stenosis (≥70%), FA values in the cerebral white matter were derived from DTI before and 1 month after surgery and were analyzed by using tract-based spatial statistics. Neuropsychological testing, consisting of the Wechsler Adult Intelligence Scale Revised, the Wechsler Memory Scale and the Rey-Osterreith Complex Figure test, was also performed preoperatively and after the first postoperative month.
  
  
  RESULTS
  Based on the neuropsychological assessments, 11 (14%) patients were defined as having postoperatively improved cognition. The difference between the 2 mean FA values (postoperative values minus preoperative values) in the cerebral hemisphere ipsilateral to surgery was significantly associated with postoperative cognitive improvement (95% confidence intervals, 2.632-9.877; P = .008). White matter FA values in patients with postoperative cognitive improvement were significantly increased after surgery in the whole ipsilateral cerebral hemisphere, in the contralateral anterior cerebral artery territory, and in the watershed zone between the contralateral anterior and middle cerebral arteries.
  
  
  CONCLUSIONS
  Postoperative increase in cerebral white matter FA on DTI is associated with cognitive improvement after uncomplicated CEA.
authors.affiliation: *Department of Neurosurgery, Iwate Medical University School of Medicine, Morioka, Japan; ‡Division of Ultra-High Field MRI and Department of Radiology, Iwate Medical University School of Medicine, Morioka, Japan; §Department of Disaster Medicine, Iwate Medical University School of Medicine, Morioka, Japan.
authors.forename: Yuiko
authors.initials: Y
authors.lastname: Sato
authors.forename: Kenji
authors.initials: K
authors.lastname: Ito
authors.forename: Kuniaki
authors.initials: K
authors.lastname: Ogasawara
authors.forename: Makoto
authors.initials: M
authors.lastname: Sasaki
authors.forename: Kohsuke
authors.initials: K
authors.lastname: Kudo
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Murakami
authors.forename: Takamasa
authors.initials: T
authors.lastname: Nanba
authors.forename: Hideaki
authors.initials: H
authors.lastname: Nishimoto
authors.forename: Kenji
authors.initials: K
authors.lastname: Yoshida
authors.forename: Masakazu
authors.initials: M
authors.lastname: Kobayashi
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Kubo
authors.forename: Tomohiko
authors.initials: T
authors.lastname: Mase
authors.forename: Akira
authors.initials: A
authors.lastname: Ogawa
mesh_terms: D000368:Aged; D016880:Anisotropy; D001921:Brain / Q000473:pathology* / Q000601:surgery; D016893:Carotid Stenosis / Q000150:complications / Q000601:surgery*; D003072:Cognition Disorders / Q000209:etiology / Q000601:surgery*; D038524:Diffusion Magnetic Resonance Imaging; D056324:Diffusion Tensor Imaging; D016894:Endarterectomy, Carotid; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008297:Male; D008875:Middle Aged; D009413:Nerve Fibers, Myelinated / Q000473:pathology*; D009483:Neuropsychological Tests