Reproducibility and accuracy of non-invasive measurement of infarct size in mice with high-resolution PET/CT

This study assessed the reproducibility and accuracy of 2-deoxy-2[¹⁸F]fluoro-d-glucose (¹⁸F-FDG) for non-invasive quantification of myocardial infarct size in mice by a high-resolution positron emission tomography (PET)/computed tomography (CT) system.

Mice were studied by ¹⁸F-FDG PET/CT 1 week after induction of myocardial infarction by permanent coronary occlusion or sham procedure. In a subset of mice, PET/CT was repeated 2 days apart to assess the reproducibility of infarct size measurements. Histological analysis was used as reference method to validate imaging data. The average difference in infarct size measurements between the first and the second study was −0.42% ± 2.07% (95% confidence interval −2.6 to 1.75) with a repeatability coefficient of 4.05%. At Bland-Altman analysis, the lower and upper limits of agreement between the two repeated studies were −4.46% and 3.63%, respectively, and no correlation between difference and mean was found (P = .89). The concordance correlation coefficient was 0.99 (P < .001) and the intraclass coefficient of correlation was 0.99. A high correlation between PET/CT and histology was found for measurement of infarct size (P < .001). Using Bland-Altman analysis, the mean difference in infarct size measurement (PET/CT minus histology) was 1.9% (95% confidence interval 0.94% to 2.86%).

In a mice model of permanent coronary occlusion non-invasive measurement of infarct size with high-resolution ¹⁸F-FDG, PET/CT has excellent reproducibility and accuracy. These findings support the use of this methodology in serial studies.