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Diffusion weighted imaging and magnetic resonance spectroscopy in a low flow ischaemia model due to endothelin induced vasospasm
Author(s) -
Domingo Z.,
Bradley J. K.,
Blamire A. M.,
Brindle K.,
Styles P.,
Rajagopalan B.
Publication year - 2000
Publication title -
nmr in biomedicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.278
H-Index - 114
eISSN - 1099-1492
pISSN - 0952-3480
DOI - 10.1002/1099-1492(200005)13:3<154::aid-nbm620>3.0.co;2-w
Subject(s) - vasospasm , phosphocreatine , intravoxel incoherent motion , medicine , nuclear magnetic resonance , effective diffusion coefficient , ischemia , chemistry , nuclear magnetic resonance spectroscopy , adenosine triphosphate , magnetic resonance imaging , cerebral ischaemia , anesthesia , subarachnoid hemorrhage , cardiology , radiology , energy metabolism , stereochemistry , physics
The aim of this MR study was to determine if vasospasm induced by application of endothelin‐1 (ET‐1) in the rat brain would model the abnormalities attributed to vasospasm described in patients with subarachnoid haemorrhage (SAH) with reversible neurological deficits. Following application of ET‐1 in concentrations of 10 −4 M or 10 −6 M to the middle cerebral artery, there was an immediate drop in pH, an increase in the inorganic phosphate (P i ) to phosphocreatine (PCr) ratio and elevated lactate. There was gradual recovery to control in the 10 −6 M group, but in the 10 −4 M group there was a loss of approximately 10% in the absolute signal intensities of PCr and adenosine triphosphate (ATP). In a second similarly treated group of animals, the area of the hemisphere with a low apparent diffusion coefficient (ADC) was 27 ± 6% at 30 min and remained at about 20–21% at 90 min and beyond. Together these data suggest that the regions with persistently low ADC were metabolically compromised, with incomplete recovery of PCr and ATP, and represent irreversibly damaged tissue. This raises the possibility that MR spectroscopy and imaging could be a sensitive indicator of tissue viability. This is a potentially useful model of low flow as seen in clinical vasospasm following SAH. Copyright © 2000 John Wiley & Sons, Ltd.