Abstract

OJEDA-FLORES, Rafael et al. Cardiac metabolism and perfusion evaluation in a rat model using ¹⁸F-FDG,1- ¹¹C-acetate, ¹³NH₃ and micro-positron emission tomography (microPET). Arch. Cardiol. Méx. [online]. 2010, vol.80, n.4, pp.215-228. ISSN 1665-1731.

Objective: To standardize an acquisition protocol for the study of myocardial glucolitic and oxidative metabolism and perfusion in a rat model. Methods: Studies were carried out with the three main radiopharmaceuticals used to assess heart function:[¹⁸F]-FDG for glucolitic metabolism; [1-¹¹C]-acetate for oxidative metabolism and [¹³N]-NH₃for myocardial perfusion.[¹⁸F]-FDG -Five Wistar adult male rats were studied in three different protocols: non-fasting group, fasting group,8 h before the study with water provided ad libitum, and a fasting group by the same time receiving an oral 50%-glucose solution. Thirty-minute scans were performed with a microPET Focus 120, 30 and 60 min after the administration of 370-555 MBq 18F-FDG. [1-¹¹C]-Acetate -Eight rats were studied. Four static and four dynamic 30 min acquisitions after a 370-555 MBq of [1-¹¹C]-acetate caudal vein administration.[¹³N]-NH₃-Ten static studies were acquired 15 min post-administration of 370555 MBqof¹³NH₃, under 1.5-2% isofluorane anesthesia. Comparative and visual analyses were performed by two experts in the field. A semi-quantitative analysis was performed using 3D reconstructions and ROI selections with AMIDE software. Results: The best images were those obtained from the non-fasting group, especially those taken at 60 min after the [¹⁸F]-FDG administration. High quality myocardial, static images were obtained with [1-¹¹C]-acetate, and the dynamic acquisitions allowed the identification of myocardial perfusion. The ¹³NH₃images showed a homogeneous distribution of the radiotracer in different segments of the short, long and horizontal axes in the left ventricle. Conclusions: It is possible to standardize the microPET acquisition protocols for the three main radiopharmaceuticals to evaluate the heart function in a rat model. It is feasible to establish a valid protocol for measuring glucolitic and oxidative myocardial metabolism and perfusion for gene, drug or surgical therapy assessment.

Keywords : ¹⁸F-FDG; 1-¹¹C-acetate; ¹³NH₃; MicroPET; Myocardial Viability; Mexico.

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