Simultaneous cardiac positron emission tomography and magnetic resonance (PETMR) imaging is a promising non-invasive hybrid technique for comprehensive assessment of cardiovascular disease in a single examination. However, image degradation due to respiratory and cardiac motion during data acquisition remains a major challenge that has hindered the adoption of PET-MR in the clinical setting. State-of-the-art PET-MR technical developments have focused on using MR information for improving PET image quality. However, this significantly increases the overall examination time, since diagnostic MR images need to be acquired after the PET-MR scan. Furthermore, this approach leads to misaligned PET and MR images that are difficult to interpret together. In this thesis a novel framework for truly simultaneous motion-corrected cardiac PET-MR has been developed. This was achieved by designing an MR acquisition sequence that allowed the measurement of physiological respiratory and cardiac motion while producing coronary MR angiography (CMRA) images, and a reconstruction scheme that included this motion information to produce co-registered motion-corrected cardiac PET and CMRA images from a single efficient examination with short and predictable scan time. This general framework was implemented for three applications. First, a scheme that enables respiratory motion-corrected PET-CMRA was developed. The scheme was validated in healthy subjects, oncology patients and patients with cardiac disease, enabling assessment of myocardial viability by PET and visualisation of coronary artery anatomy by CMRA. The second application extended this scheme to include both cardiac and respiratory motion-correction of PET and CMRA data. In this approach, left ventricular function can also be measured by MR, potentially allowing for a comprehensive assessment of coronary artery disease from a single scan of 12 minutes. Finally, the proposed scheme was extended to perform water-fat CMRA imaging, enabling the simultaneous visualisation of coronary anatomy and cardiac fat, and estimation of respiratory-resolved attenuation correction maps to further improve the quantification of the cardiac PET images.
Motion-Corrected Simultaneous Cardiac PET-MR Imaging
Munoz, C. (Author). 1 Apr 2019
Student thesis: Doctoral Thesis › Doctor of Philosophy