Noninvasive measurement of myocardial activity concentrations and perfusion defect sizes in rats with a new small-animal positron emission tomograph.
BACKGROUND
We explored the feasibility of measuring regional tracer activity concentrations and flow defects in myocardium of rats with a high spatial resolution small-animal PET system (microPET).


RESULTS
Myocardial images were obtained after intravenous (18)F-fluorodeoxyglucose (18FDG) in 11 normal rats (group 1) and assembled into polar maps. Regional 18F activity concentrations were measured in 9 regions of interest and compared with tissue activity concentrations measured by well counting. In another 9 rats (group 2), myocardial perfusion images were acquired with 13N-ammonia at baseline and during coronary occlusion. On the polar maps recorded during coronary occlusion, the size of perfusion defects was measured as the myocardium with <50% of maximum activity and expressed as percent total myocardium and was correlated with the area at risk defined by postmortem staining. The diagnostic quality of 18FDG and 13N-ammonia microPET images was good to excellent; the images were easily assembled into polar maps. In group 1, regional (18)F concentrations by microPET and postmortem were correlated linearly (r=0.99; P<0.01 for average and r=0.97; P<0.01 for regional concentrations). In group 2, perfusion defect sizes by microPET and postmortem were correlated linearly (P<0.01; r=0.93).


CONCLUSIONS
The findings indicate the feasibility of noninvasive studies of the myocardium in rats with a dedicated small-animal PET-imaging device.
Kudo
Takashi
T
Crump Institute for Molecular Imaging, Laboratory of Structural Biology and Molecular Medicine and Department of Molecular and Medical Pharmacology, UCLA School of Medicine, University of California at Los Angeles, 90095-1735, USA.
Fukuchi
Kazuki
K
Annala
Alexander J
AJ
Chatziioannou
Arion F
AF
Allada
Vivekanand
V
Dahlbom
Magnus
M
Tai
Yuan-Chuan
YC
Inubushi
Masayuki
M
Huang
Sung-Cheng
SC
Cherry
Simon R
SR
Phelps
Michael E
ME
Schelbert
Heinrich R
HR
D000818:Animals; D003326:Coronary Circulation; D003327:Coronary Disease / Q000000981:diagnostic imaging*; D005240:Feasibility Studies; D019788:Fluorodeoxyglucose F18; D006321:Heart / Q000000981:diagnostic imaging*; D008297:Male; D023421:Models, Animal; D051381:Rats; D017207:Rats, Sprague-Dawley; D014055:Tomography, Emission-Computed / Q000379:methods*
D019788:Fluorodeoxyglucose F18