In:
Journal of Cerebral Blood Flow & Metabolism, SAGE Publications, Vol. 9, No. 6 ( 1989-12), p. 859-873
Abstract:
A practical method has been developed that, using 11 CO 2 and positron emission tomography (PET), computes and maps (a) “effective pH” (pH t ), a weighted average of intra- and extracellular pH, and (b) “clearance” ( K 1 ), product of blood flow and 11 CO 2 extraction. This method, together with measurements of cerebral blood flow (CBF) and oxygen extraction fraction (OEF), was applied to 12 patients with cerebral ischemia or stroke. The regional K 1 was positively correlated with CBF ( n = +0.78). The k 1 /CBF ratio, representing the extraction fraction ratio of 11 CO 2 to H 2 15 O, was negatively correlated with CBF ( r = –0.54), suggesting that 11 CO 2 extraction decreases as flow increases. In five acute stroke patients within 2 days of onset, the injured cortex had lower CBF (20.6 ml/min/100 g), higher OEF (78.1%), and lower pH t (6.96) than the contralateral cortex (CBF = 41.4 ml/min/100 g, OEF = 53.3%, pH t = 7.00), suggesting intracellular acidosis with intact cell membranes. In three stroke patients 5–8 days after onset, the injured cortex had higher CBF (60.9 ml/min/100 g), lower OEF (32.0%), and higher pH t (7.12) than the contralateral cortex (CBF = 45.3 ml/min/100 g, OEF = 58.0%, pH t = 7.06), which suggested an increase in extracellular volume compartment reflecting loss of cell membrane integrity. This method provides information on the regional tissue acid–base status and cell membrane integrity, which may be prognostic of tissue viability.
Type of Medium:
Online Resource
ISSN:
0271-678X
,
1559-7016
DOI:
10.1038/jcbfm.1989.120
Language:
English
Publisher:
SAGE Publications
Publication Date:
1989
detail.hit.zdb_id:
2039456-1
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