ECG-triggered 18F-fluorodeoxyglucose positron emission tomography imaging of the rat heart is dramatically enhanced by acipimox.
OBJECTIVE
18F-Fluorodeoxyglucose (FDG) imaging, provided by current positron emission tomography (PET) systems dedicated to small animals,might provide a precise functional assessment of the left ventricle (LV) in rats, although conventional metabolic conditioning by hyperinsulinaemic glucose clamping is not well adapted to this setting. This study was aimed at assessing cardiac FDG PET in rats premedicated with acipimox, a potent nicotinic acid derivative yielding comparable image quality to clamping in man.


METHODS
Metabolic conditioning was compared in Wistar rats between a conventional oral glucose loading (1.5 mg/kg) and acipimox, which was given at high but well tolerated doses subcutaneously (25 mg/kg) or orally (50 mg/kg). Myocardial to blood (M/B) activity ratio and myocardial signal to noise (S/N) ratio were analysed on gated FDG PET images.


RESULTS
The S/N ratio of the gated cardiac images evolved in parallel with the M/B activity ratio and these two ratios were independently enhanced by glucose loading and acipimox. However, these enhancements were: (1) dramatic for acipimox, especially for the high oral dose of 50 mg/kg (from 2.85 +/- 0.57 to 10.73 +/- 0.54 for the M/B ratio of rats with or without glucose loading; p<0.0001) and (2) much more limited for glucose loading (from 6.61 +/- 0.49 to 7.89 +/- 0.41 for the M/B ratio of rats with or without acipimox administration; p=0.049). With the high oral dose of acipimox, the gated cardiac FDG PET images had very high S/N ratios, at least equivalent to those currently documented in man.


CONCLUSIONS
Metabolic conditioning by oral doses of acipimox is highly efficient for experimental studies planned with cardiac FDG PET in rats.
Poussier
Sylvain
S
Nancyclotep, Experimental Imaging Platform, Nancy, France. Sylvain.Poussier@medecine.uhp-nancy.fr
Maskali
Fatiha
F
Tran
Nguyen
N
Person
Christophe
C
Maureira
Pablo
P
Boutley
Henri
H
Karcher
Gilles
G
Lacolley
Patrick
P
Régnault
Véronique
V
Fay
Renaud
R
Marie
Pierre Yves
PY
D000818:Animals; D055424:Cardiac-Gated Imaging Techniques; D004305:Dose-Response Relationship, Drug; D004562:Electrocardiography; D019788:Fluorodeoxyglucose F18; D005947:Glucose / Q000008:administration & dosage / Q000494:pharmacology; D006321:Heart / Q000000981:diagnostic imaging* / Q000187:drug effects* / Q000502:physiology; D008297:Male; D049268:Positron-Emission Tomography / Q000379:methods*; D011719:Pyrazines / Q000008:administration & dosage / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D016277:Ventricular Function, Left / Q000187:drug effects
D011719:Pyrazines; D019788:Fluorodeoxyglucose F18; D005947:Glucose; C027696:acipimox
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