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Value of cerebral blood flow rate and regional oxygen consumption studies in cerebral ischaemia

Conference:

Abstract

Studies of experimentally-induced ischaemia have shown that the intensity of neuronal suffering is related to the fall in perfusion rate. Below a certain level, called functional threshold, cerebral function is reversibly altered, whereas at a lower level (tissue necrosis threshold) the damage inflicted on neurons is irreversible. Between these two thresholds lies a ''penumbra zone''. This concept of thresholds must be mitigated by 2 parameters: duration of ischaemia and selective vulnerability of the various structures affected. Variations in blood flow rate only indirectly affect the state of tissues. Techniques developed from positron emission tomography make it possible to evaluate the metabolic activity of brain tissue in vivo: oxygen consumption (CMRO/sub 2/), oxygen extraction (EO/sub 2/) and glucose consumption (CMRG) which are thus correlated to cerebral blood flow and cerebral blood volume, sometimes also to tissue pH. Normal relations between blood flow rate and metabolism may be altered. Misery perfusion reflects a fall in cerebral blood flow with an increase in EO/sub 2/ and often a decrease in CMRO/sub 2/, whereas luxury perfusion reflects an increase in cerebral blood flow rate with reduction of CMRO/sub 2/, EO/sub 2/ and CMRG. The type of alteration encountered in human ischaemia varies according to  More>>
Authors:
Publication Date:
Jun 18, 1987
Product Type:
Conference
Report Number:
CONF-8610348-
Reference Number:
FRD-87-003108; EDB-88-003268
Resource Relation:
Journal Name: Presse Med.; (France); Journal Volume: 16:23; Conference: 2. international symposium on cerebral ischemia and Alzheimer disease, Madrid, Spain, 3 Oct 1986
Subject:
62 RADIOLOGY AND NUCLEAR MEDICINE; BRAIN; POSITRON COMPUTED TOMOGRAPHY; ISCHEMIA; DIAGNOSIS; BLOOD FLOW; DYNAMIC FUNCTION STUDIES; FLOW RATE; FLUORINE 18; GLUCOSE; METABOLISM; OXYGEN 15; PATIENTS; ALDEHYDES; BETA DECAY RADIOISOTOPES; BETA-PLUS DECAY RADIOISOTOPES; BODY; CARBOHYDRATES; CARDIOVASCULAR DISEASES; CENTRAL NERVOUS SYSTEM; COMPUTERIZED TOMOGRAPHY; DIAGNOSTIC TECHNIQUES; DISEASES; EMISSION COMPUTED TOMOGRAPHY; EVEN-ODD NUCLEI; FLUORINE ISOTOPES; HEXOSES; HOURS LIVING RADIOISOTOPES; ISOTOPES; LIGHT NUCLEI; MINUTES LIVING RADIOISOTOPES; MONOSACCHARIDES; NERVOUS SYSTEM; NUCLEI; ODD-ODD NUCLEI; ORGANIC COMPOUNDS; ORGANS; OXYGEN ISOTOPES; RADIOISOTOPES; SACCHARIDES; TOMOGRAPHY; VASCULAR DISEASES; 550601* - Medicine- Unsealed Radionuclides in Diagnostics
OSTI ID:
5891139
Research Organizations:
Service de Neurologie, CHU Purpan, 31 - Toulouse, France
Country of Origin:
France
Language:
French
Other Identifying Numbers:
Journal ID: CODEN: PRMEA
Submitting Site:
FRN
Size:
Pages: 1135-1138
Announcement Date:

Conference:

Citation Formats

Clanet, M. Value of cerebral blood flow rate and regional oxygen consumption studies in cerebral ischaemia. France: N. p., 1987. Web.
Clanet, M. Value of cerebral blood flow rate and regional oxygen consumption studies in cerebral ischaemia. France.
Clanet, M. 1987. "Value of cerebral blood flow rate and regional oxygen consumption studies in cerebral ischaemia." France.
@misc{etde_5891139,
title = {Value of cerebral blood flow rate and regional oxygen consumption studies in cerebral ischaemia}
author = {Clanet, M}
abstractNote = {Studies of experimentally-induced ischaemia have shown that the intensity of neuronal suffering is related to the fall in perfusion rate. Below a certain level, called functional threshold, cerebral function is reversibly altered, whereas at a lower level (tissue necrosis threshold) the damage inflicted on neurons is irreversible. Between these two thresholds lies a ''penumbra zone''. This concept of thresholds must be mitigated by 2 parameters: duration of ischaemia and selective vulnerability of the various structures affected. Variations in blood flow rate only indirectly affect the state of tissues. Techniques developed from positron emission tomography make it possible to evaluate the metabolic activity of brain tissue in vivo: oxygen consumption (CMRO/sub 2/), oxygen extraction (EO/sub 2/) and glucose consumption (CMRG) which are thus correlated to cerebral blood flow and cerebral blood volume, sometimes also to tissue pH. Normal relations between blood flow rate and metabolism may be altered. Misery perfusion reflects a fall in cerebral blood flow with an increase in EO/sub 2/ and often a decrease in CMRO/sub 2/, whereas luxury perfusion reflects an increase in cerebral blood flow rate with reduction of CMRO/sub 2/, EO/sub 2/ and CMRG. The type of alteration encountered in human ischaemia varies according to the nature of the accident: studies of transient accidents emphasize the different haemodynamic aspects of occlusion of the wider arteries. The metabolic and haemodynamic profiles of established ischaemic accidents vary according to their type and to the time of the study, reflecting the complexity of the physiopathological mechanisms involved; they are frequently associated with metabolic repercussions at a distance from the ischaemic focus, which supports the concept of diaschisis.}
journal = {Presse Med.; (France)}
volume = {16:23}
place = {France}
year = {1987}
month = {Jun}
}