Reversal of focal "misery-perfusion syndrome" by extra-intracranial arterial bypass in hemodynamic cerebral ischemia. A case study with 15O positron emission tomography.

Abstract

SUMMARY Tomogrephic images of cerebral blood flow (CBF) and oxygen extraction fraction (OEF) using the U O continuous inhalation technique, and positron emission tomography, were obtained from a patient with cerebral ischemia distal to an occluded left internal carotid artery. There was a focal mismatch between CBF and oxygen metabolism in the brain supplied by tbe middle cerebral artery where CBF was decreased and OEF increased ("misery-perfusion syndrome" as opposed to "luxury-perfusioa syndrome"). These abnormalities were most marked in tbe parieto-ocdpital watershed area. After left superficial temporal to middle cerebral artery anastomosis, the clinical attacks ceased and a repeat study did not demonstrate tbe prerious CBF and OEF abnormalities. This suggests that this pattern of abnormalities indicates potential liable tissue. The concept of "mlsery-perfuslon" may be of some importance In tbe patbophysiological mechanisms of hemodynamic cerebral ischemia and serve as a rational basis for rerascularization procedures.

Evaluation of the cerebral vasodilatory capacity by the acetazolamide test before EC-IC bypass surgery in patients with occlusion of the internal carotid artery.

“…Thus, the common preoperative finding of a reduced flow in the peri-infarct areas -and the occasional finding of a focal low flow area in patients without any CT lesions whatsoever -therefore suggests, in most but not all instances, that permanent ischemic lesion has occurred. This interpretation is supported by the findings by Gibbs et al , 3 who showed that the oxygen utilization was reduced in the presence of more than adequate oxygen delivery. We have previously discussed the possible pathogenetic mechanisms to this finding, and have considered disconnection or diffuse but selective neuronal cell loss or microscopic infarcts as likely explanations.…”

Early Disrupted Neurovascular Coupling and Changed Event Level Hemodynamic Response Function in Type 2 Diabetes: An fMRI Study

“…Neuronal activation imposes an increase in oxygen demand in functionally relevant brain areas, which is managed by regulatory increases in blood supply to optimize oxygen supply. 36 In the presence of cerebrovascular disease, the oxygen reserve may not be sufficient to respond to the stimulus, resulting in a loss of autoregulation. 37,38 In this situation, the standard HRF is changed and induces subsequent alterations in the BOLD signal time course.…”

Perfusion criteria of the EICMA efficacy in patients with symptomatic occlusion of the internal carotid artery

“…Это можно объяснить не-однородностью изменений перфузии в полушарии на стороне окклюзии, особенно у больных с послед-ствиями завершенного ишемического инсульта. В подобных случаях регистрировались локальные зоны выраженной гипоперфузии преимущественно в области белого вещества и зонах смежного крово-обращения, которые нивелировались усиленным компенсированным кровотоком в корковых обла-стях и бассейнах передней и задней мозговых арте-рий, учитывая умеренную асимметрию полушарно-го кровотока, данная степень перфузионного дефи-цита была наиболее близка к I стадии цереброваску-лярной недостаточности по Барону [12][13][14], однако неоднородность церебральной перфузии в пределах оригинальные статьи пораженного полушария у больных с последствия-ми ишемического инсульта не позволили рассма-тривать ее как вариант компенсации мозгового кро-вотока. В частности, в области белого вещества и зон смежного кровообращения асимметрия средне-го времени транзита крови превышала 80% по срав-нению со здоровым полушарием, со снижением CBF более 40%, что соответствовало пороговым значениям области с повышенным риском развития ишемии [11,15,16].…”