Fernando E. Boada, Ph.D.
Professor of Radiology, Psychiatry and Neurosurgery
Director, Center for Advanced Imaging Innovation and Research
Co-Director, Center for Biomedical Imaging
New York University


“MR/PET Synergies: Correcting Motion During Dynamic MR/PET Scans Through Self
Refocused Navigators and Coil Fingerprints”

Abstract:
MR/PET scanners allow simultaneous acquisition of MR and PET scans during clinical examinations. This feature has great potential to improve our ability to capitalize on PET’s unique capabilities to probe important metabolic processes in vivo. Examples include: improving image quality for low specific activity tracers through the use of joint MR/PET reconstruction, reduction of radiation exposure (90%) for standard-of-care Fluorodeoxyglucose (FDG) scans, improvement of tracer kinetic analysis and motion correction of dynamic PET scans. Motion correction of dynamic PET scans, in particular, is an unmet challenge as the use of external gating signals for retrospective motion correction has proven unreliable for a variety of different reasons. In this presentation, we demonstrate an approach for motion correction of MR/PET scans based on the use of short, self-refocused, multidimensional navigator modules. These modules allow continuous (every TR) tracking of abdominal motion through monitoring of the time course of the “generalized projections” spatially encoded by the navigator modules. We demonstrate, using in-vivo as well as motion phantom data, that these modules are compatible with both 3D and 2D MRI- sequences and that their use allows the removal of large (60%) quantitative biases in PET scans due to multi-dimensional (i.e., cardiac and respiratory) motion blur.