MR imaging of microcirculation in rat brain: correlation with carbon dioxide-induced changes in blood flow.
Considerable interest has been shown in developing a magnetic resonance (MR) imaging technique with quantitative capability in the evaluation of tissue microcirculation ("perfusion"). In the present study, the flow-dephased/flow-compensated (FD/FC) technique is evaluated for measuring rat cerebral blood flow (CBF) under nearly optimal laboratory conditions. Imaging was performed on a 2.0-T system equipped with shielded gradient coils. Rat CBF was varied by manipulating arterial carbon dioxide pressure (PaCO2). In parallel experiments, optimized MR imaging studies (seven rats) were compared with laser Doppler flowmetry (LDF) studies (nine rats). LDF values showed a high degree of correlation between CBF and PaCO2, agreeing with results in the literature. MR imaging values, while correlating with PaCO2, showed considerable scatter. The most likely explanation is unavoidable rat motion during the requisite long imaging times. Because of this motion sensitivity, the FD/FC technique cannot provide a quantitative measure of CBF. It can, however, provide a qualitative picture.
Maki
J H
JH
Department of Radiology, Duke University Medical Center, Durham, NC 27710.
Benveniste
H
H
MacFall
J R
JR
Piantadosi
C A
CA
Johnson
G A
GA
D000818:Animals; D016477:Artifacts; D001921:Brain / Q000098:blood supply*; D002245:Carbon Dioxide / Q000097:blood*; D002540:Cerebral Cortex / Q000098:blood supply; D002560:Cerebrovascular Circulation / Q000502:physiology*; D003342:Corpus Striatum / Q000098:blood supply; D005260:Female; D007089:Image Enhancement / Q000379:methods*; D007834:Lasers; D016014:Linear Models; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008833:Microcirculation / Q000502:physiology*; D008961:Models, Structural; D009038:Motion; D051381:Rats; D011919:Rats, Inbred Strains
D002245:Carbon Dioxide