title: MR-based attenuation correction for cardiac FDG PET on a hybrid PET/MRI scanner: comparison with standard CT attenuation correction.
abstract: OBJECTIVE
  The aim of this study was to evaluate the feasibility of attenuation correction (AC) for cardiac (18)F-labelled fluorodeoxyglucose (FDG) positron emission tomography (PET) using MR-based attenuation maps.
  
  
  METHODS
  We included 23 patients with no known cardiac history undergoing whole-body FDG PET/CT imaging for oncological indications on a PET/CT scanner using time-of-flight (TOF) and subsequent whole-body PET/MR imaging on an investigational hybrid PET/MRI scanner. Data sets from PET/MRI (with and without TOF) were reconstructed using MR AC and semi-quantitative segmental (20-segment model) myocardial tracer uptake (per cent of maximum) and compared to PET/CT which was reconstructed using CT AC and served as standard of reference.
  
  
  RESULTS
  Excellent correlations were found for regional uptake values between PET/CT and PET/MRI with TOF (n = 460 segments in 23 patients; r = 0.913; p < 0.0001) with narrow Bland-Altman limits of agreement (-8.5 to +12.6 %). Correlation coefficients were slightly lower between PET/CT and PET/MRI without TOF (n = 460 segments in 23 patients; r = 0.851; p < 0.0001) with broader Bland-Altman limits of agreement (-12.5 to +15.0 %). PET/MRI with and without TOF showed minimal underestimation of tracer uptake (-2.08 and -1.29 %, respectively), compared to PET/CT.
  
  
  CONCLUSIONS
  Relative myocardial FDG uptake obtained from MR-based attenuation corrected FDG PET is highly comparable to standard CT-based attenuation corrected FDG PET, suggesting interchangeability of both AC techniques.
authors.affiliation: Department of Nuclear Medicine, University Hospital Zurich, Ramistrasse 100, 8091, Zurich, Switzerland.
authors.forename: Jan
authors.initials: J
authors.lastname: Vontobel
authors.forename: Riccardo
authors.initials: R
authors.lastname: Liga
authors.forename: Mathias
authors.initials: M
authors.lastname: Possner
authors.forename: Olivier F
authors.initials: OF
authors.lastname: Clerc
authors.forename: Fran
authors.initials: F
authors.lastname: Mikulicic
authors.forename: Patrick
authors.initials: P
authors.lastname: Veit-Haibach
authors.forename: Edwin E G W
authors.initials: EE
authors.lastname: Ter Voert
authors.forename: Tobias A
authors.initials: TA
authors.lastname: Fuchs
authors.forename: Julia
authors.initials: J
authors.lastname: Stehli
authors.forename: Aju P
authors.initials: AP
authors.lastname: Pazhenkottil
authors.forename: Dominik C
authors.initials: DC
authors.lastname: Benz
authors.forename: Christoph
authors.initials: C
authors.lastname: Gräni
authors.forename: Oliver
authors.initials: O
authors.lastname: Gaemperli
authors.forename: Bernhard
authors.initials: B
authors.lastname: Herzog
authors.forename: Ronny R
authors.initials: RR
authors.lastname: Buechel
authors.forename: Philipp A
authors.initials: PA
authors.lastname: Kaufmann
mesh_terms: D000328:Adult; D000368:Aged; D000465:Algorithms; D016477:Artifacts; D057791:Cardiac Imaging Techniques / Q000295:instrumentation / Q000379:methods*; D005240:Feasibility Studies; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000493:pharmacokinetics*; D006801:Humans; D007089:Image Enhancement / Q000295:instrumentation / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000295:instrumentation / Q000379:methods*; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging / Q000295:instrumentation / Q000379:methods; D009206:Myocardium / Q000378:metabolism; D049268:Positron-Emission Tomography / Q000295:instrumentation / Q000379:methods*; D019275:Radiopharmaceuticals; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18