title: Feasibility of simultaneous PET/MR in diet-induced atherosclerotic minipig: a pilot study for translational imaging.
abstract: Novel hybrid 18-fluoro-deoxy-D-glucose ((18)F-FDG) based positron emission tomography (PET) and magnetic resonance imaging (MRI) has shown promise for characterization of atherosclerotic plaques clinically. The purpose of this study was to evaluate the method in a pre-clinical model of diet-induced atherosclerosis, based on the Göttingen minipig. Using (18)F-FDG PET/MRI the goal was to develop and create a new imaging method in an in vivo animal model for translational studies of atherosclerosis. We used a strategy of multisequence MRI for optimal anatomical imaging of the abdominal aortas of the pigs (n=4): T1-weighted turbo spin-echo (T1-TSE), T2-weighted turbo spin-echo (T2-TSE) and proton density imaging with and without fat saturation. (18)F-FDG PET emission data were collected from a single bed position of the abdominal aorta in 3D mode for either 10 (n=4) or 10 and 20 minutes (n=2) to measure glycolysis as given by standardized uptake values (SUV). Ex vivo en face evaluation of aortas from an atherosclerotic animal illustrated plaque distribution macroscopically, compared to a lean control animal. Although T2-TSE weighted imaging was most consistent, no one MRI sequence was preferable and superior to another for visualization and identification of the abdominal aorta. We found poor correlation between SUVs obtained from 10 and 20 minutes of reconstructed PET emission data. This can most likely be ascribed to intestinal movement. In conclusion multisequence MRI is recommended for optimal imaging of the abdominal aorta using MRI. Furthermore we found that 10 minutes of PET emission data seems adequate. This is the first study to demonstrate that the method of (18)F-FDG PET/MRI is feasible in minipig models of atherosclerosis, and therefore relevant in larger prospective studies. Perspectives of the method include correlation to e.g. aortic immunohistochemistry findings and a range of genomic and proteomic analyses.
authors.affiliation: Cluster for Molecular Imaging, University of Copenhagen; Department of Clinical Physiology, Nuclear Medicine & PET, Rigshospitalet, University of Copenhagen Copenhagen, Denmark.
authors.forename: Sune F
authors.initials: SF
authors.lastname: Pedersen
authors.affiliation: Department of Veterinary Disease Biology, University of Copenhagen Frederiksberg, Denmark.
authors.forename: Trine P
authors.initials: TP
authors.lastname: Ludvigsen
authors.affiliation: Department of Clinical Physiology, Nuclear Medicine & PET, Rigshospitalet, University of Copenhagen Copenhagen, Denmark.
authors.forename: Helle H
authors.initials: HH
authors.lastname: Johannesen
authors.affiliation: Department of Clinical Physiology, Nuclear Medicine & PET, Rigshospitalet, University of Copenhagen Copenhagen, Denmark.
authors.forename: Johan
authors.initials: J
authors.lastname: Löfgren
authors.affiliation: Cluster for Molecular Imaging, University of Copenhagen; Department of Clinical Physiology, Nuclear Medicine & PET, Rigshospitalet, University of Copenhagen Copenhagen, Denmark.
authors.forename: Rasmus S
authors.initials: RS
authors.lastname: Ripa
authors.affiliation: Department of Clinical Physiology, Nuclear Medicine & PET, Rigshospitalet, University of Copenhagen Copenhagen, Denmark.
authors.forename: Adam E
authors.initials: AE
authors.lastname: Hansen
authors.affiliation: Neurobiology Research Unit, Rigshospitalet, University of Copenhagen Copenhagen, Denmark.
authors.forename: Anders J
authors.initials: AJ
authors.lastname: Ettrup
authors.affiliation: Diabetes Pharmacology, Novo Nordisk A/S Måløv, Denmark.
authors.forename: Berit Ø
authors.initials: BØ
authors.lastname: Christoffersen
authors.affiliation: Diabetes Pharmacology, Novo Nordisk A/S Måløv, Denmark.
authors.forename: Henrik D
authors.initials: HD
authors.lastname: Pedersen
authors.affiliation: Department of Veterinary Disease Biology, University of Copenhagen Frederiksberg, Denmark.
authors.forename: Lisbeth H
authors.initials: LH
authors.lastname: Olsen
authors.affiliation: Cluster for Molecular Imaging, University of Copenhagen; Department of Clinical Physiology, Nuclear Medicine & PET, Rigshospitalet, University of Copenhagen Copenhagen, Denmark.
authors.forename: Liselotte
authors.initials: L
authors.lastname: Højgaard
authors.affiliation: Cluster for Molecular Imaging, University of Copenhagen; Department of Clinical Physiology, Nuclear Medicine & PET, Rigshospitalet, University of Copenhagen Copenhagen, Denmark.
authors.forename: Andreas
authors.initials: A
authors.lastname: Kjær
keywords: Atherosclerosis; Göttingen minipig; magnetic resonance imaging; novel model; positron emission tomography