title: Long-term changes of hemodynamics and metabolism after carotid artery occlusion.
abstract: OBJECTIVE
  To investigate whether in selected patients with internal carotid artery (ICA) occlusion and initially normal oxygen extraction fraction (OEF) measured with PET, subsequent changes of cerebral hemodynamics and metabolism occur during long-term follow-up and, if so, whether the changes are associated with atrophy of the corpus callosum or subsequent ischemic strokes.
  
  
  BACKGROUND
  The course of the changes in cerebral hemodynamics and metabolism after ICA occlusion remain unclear. After ICA occlusion, an increase in OEF may increase the risk of cerebral ischemia, and an increase in cortical ischemia would cause progression of callosal atrophy.
  
  
  METHODS
  The authors used PET and MRI to examine twice seven medically treated patients with unilateral ICA occlusion and initially normal OEF at intervals ranging from 24 to 64 (mean +/- SD, 42 +/- 17) months. No intervening ischemic attacks occurred between the two examinations.
  
  
  RESULTS
  In the hemisphere with ICA occlusion, OEF increased and blood flow decreased during follow-up. At the follow-up evaluation, abnormally increased OEF values were found in three patients, in whom ipsilateral ischemic strokes occurred during subsequent follow-up (18 +/- 6 months). A decrease in oxygen metabolism also occurred and was significantly correlated with the decrease of callosal size.
  
  
  CONCLUSIONS
  These preliminary findings in a small, selected patient sample suggest that in patients with ICA occlusion and initially normal OEF, deteriorations of cerebral hemodynamics and metabolism during long-term follow-up may be associated with callosal atrophy or subsequent ischemic strokes.
authors.affiliation: Department of Neurology, Faculty of Medicine, Kyoto University, Kyoto, Japan. yamauchi@shigamed.moriyama.shiga.jp
authors.forename: H
authors.initials: H
authors.lastname: Yamauchi
authors.forename: H
authors.initials: H
authors.lastname: Fukuyama
authors.forename: Y
authors.initials: Y
authors.lastname: Nagahama
authors.forename: C
authors.initials: C
authors.lastname: Oyanagi
authors.forename: H
authors.initials: H
authors.lastname: Okazawa
authors.forename: M
authors.initials: M
authors.lastname: Ueno
authors.forename: J
authors.initials: J
authors.lastname: Konishi
authors.forename: H
authors.initials: H
authors.lastname: Shio
mesh_terms: D000368:Aged; D000704:Analysis of Variance; D001921:Brain / Q000098:blood supply* / Q000378:metabolism / Q000473:pathology; D002545:Brain Ischemia / Q000209:etiology / Q000378:metabolism*; D002343:Carotid Artery, Internal / Q000000981:diagnostic imaging / Q000378:metabolism*; D016893:Carotid Stenosis / Q000150:complications / Q000175:diagnosis / Q000378:metabolism*; D003337:Corpus Callosum / Q000378:metabolism* / Q000473:pathology; D005260:Female; D005500:Follow-Up Studies; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011859:Radiography; D018709:Statistics, Nonparametric; D014055:Tomography, Emission-Computed