Image-derived input function from cardiac gated maximum a posteriori reconstructed PET images in mice.

PURPOSE: The purpose of this study was to determine if accurate image-derived input functions (IDIF) can be measured from cardiac gated positron emission tomography (PET) images reconstructed using ordered subset expectation maximization-maximum a posteriori (OSEM-MAP) without further correction.

PROCEDURES: IDIFs from the left ventricle were measured from cardiac gated PET images reconstructed using OSEM-MAP with computed tomography (CT)-based attenuation correction for five C57/BL6 mice. The accuracy of the IDIF was tested against blood samples using Bland-Altman analysis.

RESULTS

Image-derived blood radioactivity concentration values were not significantly different from sampled blood values at two late time points as determined by a paired t test (P = 0.97). Bland-Altman analysis revealed a mean difference of 0.06 μCi/ml (1%). Using kinetic analysis, the mean myocardial 2-deoxy-2-[(18)F]fluoro-D-glucose uptake rate constant based on the IDIF was comparable to values reported in the literature based on physical blood sampling.

CONCLUSIONS

Accurate IDIFs can be obtained non-invasively. Although reconstruction times are increased, no further spillover corrections are necessary for IDIFs derived from gated, OSEM-MAP reconstructed images with attenuation correction.