In vivo estimation of cerebral blood flow, oxygen consumption and glucose metabolism in the pig by [15O]water injection, [15O]oxygen inhalation and dual injections of [18F]fluorodeoxyglucose.
There is a need for suitable non-primate laboratory animals for studies of brain function by positron emission tomography (PET). To provide a comparative index of the circulatory physiology of the pig, we have applied novel PET tracer methodology to seven anaesthetized pigs, and measured cerebral regional oxygen consumption (CMR[O2]), cerebral blood flow (CBF), and cerebral glucose metabolism (CMR[glc]). Blood flow and flow-metabolism couple were estimated for selected cerebral regions of interest. We found an average hemispheric CMR(O2) of 171 +/- 18 micromol/100 cm3/min. Individual hemispheric CBF measurements varied between 33 and 41 ml/100 cm3/min, with an average of 37 +/- 3 ml/100 cm3/min at an average PaCO2 of 4.3 +/- 0.9 kPa. The blood flow dependency on arterial PCO2 was calculated from the results of the carbon dioxide response in two pigs in which the CBF measurements obeyed the equation CBF (ml/100 cm3/min) = 8.9 PaCO2 (kPa). In each pig, CMR(glc) was studied twice with a double-injection FDG method. In the first session, the values of CMR(glc) averaged 27 +/- 3 and 23 +/- 4 micromol/100 cm3/min, estimated by multilinear and linear regression analysis, respectively. In the second session, the corresponding averages were 27 +/- 3 and 24 +/- 3 micromol/100 cm3/min, respectively. The average oxygen extraction fraction was 0.46 +/- 0.09 and the oxygen-glucose ratio was 6.1 +/- 0.8. The findings indicate that the pig is suitable for PET studies of cerebral blood flow, cerebral oxygen consumption and glucose metabolism.
Poulsen
P H
PH
Position Emission Tomography Center, Aarhus General Hospital, Denmark. hoest@tiger.pet.akh.arhusamt.dk
Smith
D F
DF
Ostergaard
L
L
Danielsen
E H
EH
Gee
A
A
Hansen
S B
SB
Astrup
J
J
Gjedde
A
A
D000280:Administration, Inhalation; D000818:Animals; D002531:Cerebellum / Q000098:blood supply* / Q000378:metabolism / Q000502:physiology; D019788:Fluorodeoxyglucose F18; D005947:Glucose / Q000378:metabolism*; D007275:Injections, Intravenous; D010101:Oxygen Consumption; D010104:Oxygen Radioisotopes; D012039:Regional Blood Flow / Q000502:physiology; D013552:Swine; D014055:Tomography, Emission-Computed; D014867:Water
D010104:Oxygen Radioisotopes; D014867:Water; D019788:Fluorodeoxyglucose F18; D005947:Glucose