Cerebral blood flow measured by NMR indicator dilution in cats.
We developed techniques to assess the utility of a nuclear magnetic resonance (NMR) indicator for cerebral blood flow studies in cats, using Freon-22 for the first candidate. A PIN-diode-switched NMR experiment allowed the acquisition of an arterial as well as a cerebral fluorine-19 signal proportional to concentration vs. time in a 1.89 T magnet. Mean +/- SD blood:brain partition coefficients for Freon-22 were estimated at 0.93 +/- 0.08 for gray matter and 0.77 +/- 0.12 for white matter. Using maximum-likelihood curve fitting, estimates of mean +/- SD resting cerebral blood flow were 50 +/- 19 ml/100 g-min for gray matter and 5.0 +/- 2.0 ml/100 g-min for white matter. Hypercapnia produced the expected increases in gray and white matter blood flow. The physiologic effects of Freon-22, including an increase in cerebral blood flow itself with administration of 40% by volume, may limit its use as an indicator. Nevertheless, the NMR techniques described demonstrate the feasibility of fluorine-19-labeled compounds as cerebral blood flow indicators and the promise for their use in humans.
Ewing
J R
JR
Department of Neurology, Henry Ford Hospital, Detroit, Michigan 48202.
Branch
C A
CA
Helpern
J A
JA
Smith
M B
MB
Butt
S M
SM
Welch
K M
KM
D000818:Animals; D001812:Blood-Brain Barrier; D002415:Cats; D002560:Cerebrovascular Circulation; D005617:Chlorofluorocarbons, Methane; D005462:Fluorine Radioisotopes; D007201:Indicator Dilution Techniques; D009682:Magnetic Resonance Spectroscopy; D008955:Models, Cardiovascular
D005617:Chlorofluorocarbons, Methane; D005462:Fluorine Radioisotopes; C009755:fluorocarbon 22