title: Motor-related intracortical steal phenomenon detected by multichannel functional near-infrared spectroscopy imaging.
abstract: BACKGROUND
  Patients with severe cerebral ischemia may lose autoregulation to increase cerebral blood flow following neural activity. Although the steal phenomenon under conventional cerebral blood flow study has been known as a high-risk factor for stroke, the cerebral oxygen hemodynamics in ischemic patients during functional activation has not been thoroughly investigated. In this study, we present rare cases with intracortical steal phenomenon during motor tasks detected by multichannel functional near-infrared spectroscopy before and after surgery.
  
  
  METHODS
  The relative concentration change of oxygenated, deoxygenated and total hemoglobin in and around the primary sensorimotor cortex during contralateral hand grasping was investigated in 11 patients with severe internal carotid artery stenosis.
  
  
  RESULTS
  In 3 patients, the concentration of total hemoglobin around the primary sensorimotor cortex significantly decreased in response to motor stimulation and returned to baseline soon after termination of the motor task. This phenomenon partially disappeared postoperatively in all patients who underwent surgery. The remaining 8 patients showed no signs of total hemoglobin decrease in and around the sensorimotor cortex. In 9 patients, lack of decrease in deoxygenated hemoglobin in the center of the primary motor cortex during the motor task was observed and 3 of them showed significant increase in deoxygenated hemoglobin.
  
  
  CONCLUSIONS
  We have demonstrated that in some patients with severe ischemia, an abnormal motor-related steal phenomenon can be observed. This phenomenon can be modulated by surgical intervention and might imply the severity of ischemia.
authors.affiliation: Department of Neurosurgery, School of Medicine, Keio University, Tokyo, Japan. takiyama-jscn@umin.ac.jp
authors.forename: Takenori
authors.initials: T
authors.lastname: Akiyama
authors.forename: Takayuki
authors.initials: T
authors.lastname: Ohira
authors.forename: Toshinori
authors.initials: T
authors.lastname: Kato
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Toda
authors.forename: Maaya
authors.initials: M
authors.lastname: Orii
authors.forename: Kenji
authors.initials: K
authors.lastname: Hiraga
authors.forename: Atsushi
authors.initials: A
authors.lastname: Fukunaga
authors.forename: Masahito
authors.initials: M
authors.lastname: Kobayashi
authors.forename: Satoshi
authors.initials: S
authors.lastname: Onozuka
authors.forename: Takeshi
authors.initials: T
authors.lastname: Kawase
mesh_terms: D000368:Aged; D002545:Brain Ischemia / Q000175:diagnosis / Q000378:metabolism / Q000503:physiopathology; D002343:Carotid Artery, Internal; D016893:Carotid Stenosis / Q000175:diagnosis* / Q000378:metabolism / Q000503:physiopathology*; D002560:Cerebrovascular Circulation; D005260:Female; D006454:Hemoglobins; D006801:Humans; D008297:Male; D009048:Motor Skills; D010100:Oxygen / Q000378:metabolism; D012720:Severity of Illness Index; D019265:Spectroscopy, Near-Infrared / Q000295:instrumentation / Q000379:methods*; D013349:Subclavian Steal Syndrome / Q000175:diagnosis* / Q000378:metabolism / Q000503:physiopathology*; D013997:Time Factors
chemical_list: D006454:Hemoglobins; D010100:Oxygen