Motor-related intracortical steal phenomenon detected by multichannel functional near-infrared spectroscopy imaging.
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.
Akiyama
Takenori
T
Department of Neurosurgery, School of Medicine, Keio University, Tokyo, Japan. takiyama-jscn@umin.ac.jp
Ohira
Takayuki
T
Kato
Toshinori
T
Toda
Yasuo
Y
Orii
Maaya
M
Hiraga
Kenji
K
Fukunaga
Atsushi
A
Kobayashi
Masahito
M
Onozuka
Satoshi
S
Kawase
Takeshi
T
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
D006454:Hemoglobins; D010100:Oxygen