Widespread reduction of regional cerebral blood flow during hyperventilation-induced EEG slowing ('buildup'). Observation from subtraction of brain imaging with single photon emission computed tomography using technetium-99m hexamethyl-propyleneamine oxime.
To study the pathophysiological mechanisms of hyperventilation-induced EEG showing, i.e., the so-called 'buildup' phenomenon, changes in regional cerebral blood flow (rCBF) were investigated before and during the phenomenon in a 16-year-old woman with headache, thought to be of neurotic origin, by subtraction technique of brain images with single photon emission computed tomography using technetium-99m hexamethyl-propyleneamine oxime (99mTc-HMPAO). The tracer uptake during buildup decreased by 31-42% as compared to baseline values at rest before buildup in all of the measured regions, reflecting a widespread reduction in rCBF. Gas analyses of arterial blood collected during buildup showed a decrease in PaCO2, and increases in PaO2 and pH with a slight decrease in blood pressure and an increase in pulse rate. These results directly demonstrate a close correlation between the hyperventilation-induced EEG and rCBF changes, suggesting that the buildup phenomenon results from cerebral ischemic change, presumably due to cerebral vasoconstriction caused by the PaCO2 decrease.
Jibiki
I
I
Department of Neuropsychiatry, Kanazawa University, Japan.
Kurokawa
K
K
Matsuda
H
H
Fukushima
T
T
Yamaguchi
N
N
Hisada
K
K
D000293:Adolescent; D001921:Brain / Q000000981:diagnostic imaging / Q000503:physiopathology; D002560:Cerebrovascular Circulation / Q000502:physiology*; D004569:Electroencephalography; D005260:Female; D006801:Humans; D006985:Hyperventilation / Q000000981:diagnostic imaging / Q000503:physiopathology*; D015609:Organotechnetium Compounds; D010091:Oximes; D013382:Subtraction Technique; D019690:Technetium Tc 99m Exametazime; D015899:Tomography, Emission-Computed, Single-Photon
D015609:Organotechnetium Compounds; D010091:Oximes; D019690:Technetium Tc 99m Exametazime