A micro-SPECT imaging pilot study of myocardial perfusion in mice

Objective: demonstrate the feasibility of micro-SPECT for myocardial perfusion imaging in mice. Methods: a micro-SPECT dedicated camera with a field of view of 17 cm x 17 cm, a 1,5 mm pinhole with a focal distance of 12 cm was used. An infra millimetric linear phantom permitted to measure the planar and tomographic FWHM. Two normal adult mice were studied under gaseous anaesthesia (isoflurane 1,5%) and after IV administration of 0,1 mL of 99mTc-Sestamibi (350 MBq) in one case and 201Tl (64 MBq) in the other case. In the two cases, 48 projections of 1 mn over 180 deg C in a 64 x 64 image format with a radius of rotation of 2,5 cm were used with a 20% window centered on the photoelectric peak of 99mTc or the 71 KeV of 201Tl. Tomographic reconstruction was done with a specific ART cone beam algorithm. Results: phantoms FWHM were respectively 1.6 mm and 1.5 mm in planar and tomographic modes with a reconstructed field of view of 26 mm and 1 mm when the reconstructed field of view was 10 mm. Micro-SPECT perfusion images using a reconstructed voxel volume of 0.064 mm3 of the mice myocardium were obtained with a better anatomical resolution with Sestamibi than thallium. Conclusion: this pilot study demonstrate the potential of micro-SPECT imaging for mice nuclear cardiology. (author)