The Research On Variable Rotation Velocity For Cardiac CT Image Reconstruction

In recent years, image reconstruction of cardiac CT became a hotspot due to the wide applications of CT in medical diagnosis. Currently, fixed scan velocity for cardiac CT is used and approximate projection can only be got due to the non-synchronism between the heartbeat and scan velocity, thus, that cause the images represent artifacts.In order to improve the quality of cardiac CT image, in our method scan velocity can provide uniform projection with the same phases. The velocity varies with the heart beat, temporal resolution and control parameters to achieve a desirable temporal resolution in non-periodic heartbeat. The main contents of the paper are proposed as follows:(1)Study the characters of the cardiac motion, and ideal segmentation method based on ECG signal was introduced. Conditions which meet with the ideal segments were concluded, and on non-ideal segments reconstruction was analyzed and discussed.(2)A new scheme of variable velocity rotation is proposed for exact and approximate reconstructions in non-periodic case, the velocity v. varies with the heart beat T_i the number of sampling windows mbar and control parameters to achieve a desirable temporal resolution in non-periodic heartbeat.(3)Introduce a number of parameters to evaluate the quality of the reconstructed images from subjective and objective views, get a conclusion to evaluate the performance of different algorithms.(4)Based on the characters of cardiac CT imaging, improve several algorithms of image segment, the results proved the efficiently of the revised algorithms.