New multi-sector reconstruction for cardiac CT

We have developed a new multi-sector reconstruction for multi-slice CT with EKG-gating to improve the temporal resolution of cardiac CT imaging. The reconstruction utilizes the sub-second gantry speed and large coverage of the multi-slice CT and EKG-gating to image the heart with thin slice collimation in a single breath-hold. The scan data are taken at pitch of about 1, and gantry speed of 0.8 or 1.0 sec chosen based on the patient heart rate. Utilizing the periodicity of cardiac motion, the multi-sector reconstruction improves temporal resolution of reconstructed images up to 4 times. When the gantry speed is faster or slower than the cardiac cycle, a phase difference is created and the phase difference enables the data of current cycle to be combined with the data of the same cardiac phase in the next cardiac cycle for the same temporal resolution. If we combine two to four sectors of the data from 2 to 4 cardiac cycles to make up the data for reconstruction, the temporal resolution will be improved by 2 to 4 times. Phantom and patient studies are included to demonstrate the improvement of temporal resolution by the new multi-sector reconstruction.