Premium
Study of acute renal ischemia in the rat using magnetic resonance imaging and spectroscopy
Author(s) -
Terrier François,
Lazeyras François,
Posse Stephan,
Aue Walter P.,
Zimmermann Arthur,
Frey Brigitte M.,
Frey Felix J.
Publication year - 1989
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.1910120114
Subject(s) - ischemia , renal ischemia , nuclear magnetic resonance spectroscopy , parenchyma , magnetic resonance imaging , chemistry , kidney , renal artery , medicine , nuclear magnetic resonance , nuclear medicine , pathology , reperfusion injury , radiology , physics , organic chemistry
Magnetic resonance (MR) imaging and spectroscopy, chemical lactate measurements, and microscopic examinations were performed to investigate acute renal ischemia in rats. MR images ( 1 H) and spectra ( 31 P and 1 H) were acquired on a 2.0‐T superconducting small‐bore magnet by using implanted coils. Occlusion of the renal artery induced a significant decrease in signal intensity of the renal parenchyma on T2‐weighted images, which was most obvious in the outer medulla (‐50 ± 15%, n = 8, P 0.001) and was the result of venous congestion, as verified histologically. 31 P spectroscopy demonstrated a drop in pH from 7.3 ± 0.2 to 6.6 ± 0.2 ( n = 18, P 0.001), characterized by a time constant ( T c ) in the same range as that of the depletion of ATP (2.3 ± 1.3 min versus 1.9 ± 1.2 min, n = 10, P = ns). By means of 1 H spectroscopy, a lactate peak was detected within 1.5 to 4 min of ischemia, still increasing in intensity after 1 h of ischemia. The T c of the lactate buildup (15.9 ± 7.5 min, n = 8) was significantly longer than that of the drop in pH ( P 0.005). The chemically measured intrarenal concentration of lactate was 1.3 ± 0.5 Mmol/g in control kidneys and 8.7 ± 3.2 μmol/g ( P < 0.005) in kidneys made ischemic for 1 h. The present study demonstrated important features of acute renal ischemia: (a) acute ischemia induces venous congestion in the medulla; (b) accumulation of lactate is not the main cause of the intracellular acidification observed during ischemia. © 1989 Academic Press, Inc.