Optimized time window for cardiac CT reconstruction based on Doppler tissue imaging (DTI) data

Optimal time windowing in cardiac CT reconstruction would permit a reduction of motion artifacts. We used Doppler Tissue Imaging (DTI) in order to acquire the speed and displacement of region of interest in one direction with a high temporal resolution. Applied on different segments of coronary arteries, 3D information is recovered in three quasi orthogonal acquisitions (abdominal, parastemal and apical views). Their reproducibility was carried on five healthy subjects. This experiment will allow finding the best time window for reconstruction. A window of half the rotation time (250ms for our CT) was estimated based on minimization of the motion variation in 3D. Since we obtained a high reproducibility between the two sessions (generally < 2mm) DTI could be an interesting approach to evaluate motion in 3D. This yields more information as compared to 2D data. Future work will require additional acquisitions and experiments in order to analyze more in depth the variability and the influence of the heart rate. The collected data will be used also as input for our motion platform and CT simulation.