Combined magnetic resonance imaging and bihemispheric magnetic resonance spectroscopy in acute experimental focal cerebral ischemia.
Combined magnetic resonance imaging (MRI) and 31P-magnetic resonance spectroscopy (MRS) were employed to evaluate acute regional cerebral ischemia in cats following middle cerebral artery occlusion (MCAO). MRI changes were first reliable 3 hours after MCAO; progressive increases in T1 and T2 relaxation times were noted for 12 hours after MCAO. Immediately after MCAO, 31P-MRS revealed decreased phosphocreatine (PCr) and increased inorganic phosphate (Pi); the PCr/Pi ratio fell from 2.23 +/- 0.40 to 0.68 +/- 0.04 (p less than 0.005). This relative decrease in high energy phosphates improved significantly by 3-5 hours after MCAO (0.67 +/- 0.04 versus 1.00 +/- 0.03, p less than 0.001). By 12 hours, the ratio had increased by 27 per cent. The dissociation between the progressive MRI changes and the gradual improvement in 31P-MRS suggests a difference between the processes affecting proton distribution and phosphate metabolism in acute regional ischemia.
Levy
R M
RM
Department of Neurologic Surgery, University of California School of Medicine, San Francisco 94143.
Berry
I
I
Moseley
M E
ME
Weinstein
P R
PR
D000208:Acute Disease; D000818:Animals; D001921:Brain / Q000378:metabolism / Q000473:pathology; D002415:Cats; D005260:Female; D002546:Ischemic Attack, Transient / Q000175:diagnosis* / Q000378:metabolism; D008279:Magnetic Resonance Imaging / Q000379:methods; D009682:Magnetic Resonance Spectroscopy; D008297:Male