title: Coronary Artery PET/MR Imaging: Feasibility, Limitations, and Solutions.
abstract: The aims of this study were to describe the authors' initial experience with combined coronary artery positron emission tomographic (PET) and magnetic resonance (MR) imaging using18F-fluorodeoxyglucose (18F-FDG) and18F-sodium fluoride (18F-NaF) radiotracers, describe common problems and their solutions, and demonstrate the feasibility of coronary PET/MR imaging in appropriate patients.
  
  
  
  Recently, PET imaging has been applied to the aortic valve and regions of atherosclerosis.18F-FDG PET imaging has become established for imaging inflammation in atherosclerosis in the aorta and carotid arteries. Moreover,18F-NaF has emerged as a novel tracer of active microcalcification in the aortic valve and coronary arteries. Coronary PET imaging remains challenging because of the small caliber of the vessels and their complex motion. Currently, most coronary imaging uses combined PET and computed tomographic imaging, but there is increasing enthusiasm for PET/MR imaging because of its reduced radiation, potential to correct for motion, and the complementary information available from cardiac MR in a single scan.
  
  
  
  Twenty-three patients with diagnosed or documented risk factors for coronary artery disease underwent either18F-FDG or18F-NaF PET/MR imaging. Standard breath-held MR-based attenuation correction was compared with a novel free-breathing approach. The impact on PET image artifacts and the interpretation of vascular uptake were evaluated semiquantitatively by expert readers. Moreover, PET reconstructions with more algorithm iterations were compared visually and by target-to-background ratio.
  
  
  
  Image quality was significantly improved by novel free-breathing attenuation correction. Moreover, conspicuity of coronary uptake was improved by increasing the number of algorithm iterations from 3 to 6. Elevated radiotracer uptake could be localized to individual coronary lesions using both18F-FDG (n = 1, maximal target-to-background ratio = 1.61) and18F-NaF (n = 7, maximal target-to-background ratio = 1.55 ± 0.37), including in 1 culprit plaque post-myocardial infarction confirmed by myocardial late gadolinium enhancement.
  
  
  
  The authors provide the first demonstration of successful, low-radiation (7.2 mSv) PET/MR imaging of inflammation and microcalcification activity in the coronary arteries. However, this requires specialized approaches tailored to coronary imaging for both attenuation correction and PET reconstruction.
authors.affiliation: Translational and Molecular Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, New York. Electronic address: philip.robson@mountsinai.org.
authors.forename: Philip M
authors.initials: PM
authors.lastname: Robson
authors.affiliation: Translational and Molecular Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, New York; British Heart Foundation Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, United Kingdom.
authors.forename: Marc R
authors.initials: MR
authors.lastname: Dweck
authors.affiliation: Translational and Molecular Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, New York; Cardiovascular Institute, Icahn School of Medicine at Mount Sinai, New York, New York.
authors.forename: Maria Giovanna
authors.initials: MG
authors.lastname: Trivieri
authors.affiliation: Translational and Molecular Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, New York; Department of Nuclear Medicine, University Hospital of Brest, European University of Brittany, EA3878 GETBO, Brest, France.
authors.forename: Ronan
authors.initials: R
authors.lastname: Abgral
authors.affiliation: Translational and Molecular Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, New York.
authors.forename: Nicolas A
authors.initials: NA
authors.lastname: Karakatsanis
authors.affiliation: Cardiovascular Institute, Icahn School of Medicine at Mount Sinai, New York, New York.
authors.forename: Johanna
authors.initials: J
authors.lastname: Contreras
authors.affiliation: Cardiovascular Institute, Icahn School of Medicine at Mount Sinai, New York, New York.
authors.forename: Umesh
authors.initials: U
authors.lastname: Gidwani
authors.affiliation: Cardiovascular Institute, Icahn School of Medicine at Mount Sinai, New York, New York.
authors.forename: Jagat P
authors.initials: JP
authors.lastname: Narula
authors.affiliation: Cardiovascular Institute, Icahn School of Medicine at Mount Sinai, New York, New York.
authors.forename: Valentin
authors.initials: V
authors.lastname: Fuster
authors.affiliation: Cardiovascular Institute, Icahn School of Medicine at Mount Sinai, New York, New York.
authors.forename: Jason C
authors.initials: JC
authors.lastname: Kovacic
authors.affiliation: Translational and Molecular Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, New York; Cardiovascular Institute, Icahn School of Medicine at Mount Sinai, New York, New York.
authors.forename: Zahi A
authors.initials: ZA
authors.lastname: Fayad
mesh_terms: D000328:Adult; D000368:Aged; D000465:Algorithms; D016477:Artifacts; D003287:Contrast Media / Q000008:administration & dosage; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging*; D003331:Coronary Vessels / Q000000981:diagnostic imaging*; D005240:Feasibility Studies; D005260:Female; D005462:Fluorine Radioisotopes / Q000008:administration & dosage; D019788:Fluorodeoxyglucose F18 / Q000008:administration & dosage; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008536:Meglumine / Q000008:administration & dosage / Q000031:analogs & derivatives; D008875:Middle Aged; D064847:Multimodal Imaging / Q000379:methods*; D009942:Organometallic Compounds / Q000008:administration & dosage; D049268:Positron-Emission Tomography; D011237:Predictive Value of Tests; D019275:Radiopharmaceuticals / Q000008:administration & dosage; D015203:Reproducibility of Results; D012720:Severity of Illness Index; D012969:Sodium Fluoride / Q000008:administration & dosage; D061205:Vascular Calcification / Q000000981:diagnostic imaging*
chemical_list: D003287:Contrast Media; D005462:Fluorine Radioisotopes; D009942:Organometallic Compounds; D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18; C064572:gadobenic acid; D008536:Meglumine; D012969:Sodium Fluoride
keywords: (18F)-sodium fluoride; PET/MR imaging; atherosclerosis; attenuation correction; coronary imaging; nuclear cardiology