Static versus dynamic teboroxime myocardial perfusion SPECT in canines

Tc-99m-teboroxime is a perfusion tracer with high myocardial extraction, fa st washin and washout kinetics, and excellent imaging properties. The fast kinetics pose some problems for static imaging, but they also allow for bac k-to-back stress/rest studies to be performed very quickly. Furthermore, su ch fast kinetics are ideally suited for dynamic imaging. We have compared s tatic versus dynamic myocardial perfusion SPECT with teboroxime in canines using microsphere-derived flow values as the gold standard. Dynamic data we re successfully acquired at rest and under adenosine stress in seven dogs u sing a fast serial scanning protocol. The data were analyzed in two ways: s umming timeframes to create a single, static dataset with consistent projec tions; and 4D reconstruction and kinetic parameter estimation for a two com partment model. In both cases imaging data (voxel intensity or washin rate parameter) were correlated with flow values measured by microspheres. The s tatic summing procedure that produced the best correlation with flow consis ted of summing the projection data acquired from 60 to 180 seconds post-inj ection. The washin rate parameter was found to provide better correlation w ith flow than static image intensity in six of seven animals. When the data were pooled over all studies, washin provided significantly better correla tion with flow than static imaging (p<0.01). We conclude that dynamic imagi ng of teboroxime with compartmental modeling provides a better measure of f low than can be obtained from static imaging techniques.