Respiratory and cardiac motion correction for cardiac PET based on 2D-MRI image navigator and novel dynamic reconstruction technique

摘要

In this work we proposed a new respiratory and cardiac motion correction method for cardiac PET/MR imaging by using 2D-MRI image navigator technique and novel dynamic MRI reconstruction method. In the PET/MR acquisition, ECG trigger is used. After trigger starts, 2D-MRI image navigator and golden angle cardiac imaging sequence are applied. After acquisition, cardiac MRI data and PET data are binned to different motion phases according to 2D-MRI image navigator and ECG trigger. We use the high down sampling acquisition and novel reconstruction method based on Low-rank and Sparsity decomposition to reduce MRI acquisition time and improve the time resolution. Finally, we estimate the motion field with both cardiac and respiratory motion based on the reconstructed MRI image series. And PET images are reconstructed by OSEM algorithm based on the binned data. After reconstruction, the PET images are deformed to the same motion phase by accurate motion field from MRI. Finally, sum up all the deformed images to get corrected PET image. PET data is simulated via analytical projection method using segmented MRI images. The results of the proposed method are compared to methods with only respiratory and without motion correction. The simulation shows that the proposed method could improve the image quality and the accuracy of lesion estimation especially on the ventricular wall with cardiac motion. In conclusion, the simulation result demonstrated the feasibility and improvement of the new method.