Cardiac and Respiratory Motion Correction for Simultaneous Cardiac PET/MR.
Cardiac PET is a versatile imaging technique providing important diagnostic information about ischemic heart diseases. Respiratory and cardiac motion of the heart can strongly impair image quality and therefore diagnostic accuracy of cardiac PET scans. The aim of this study was to investigate a new cardiac PET/MR approach providing respiratory and cardiac motion-compensated MR and PET images in less than 5 min.Methods:Free-breathing 3-dimensional MR data were acquired and retrospectively binned into multiple respiratory and cardiac motion states. Three-dimensional cardiac and respiratory motion fields were obtained with a nonrigid registration algorithm and used in motion-compensated MR and PET reconstructions to improve image quality. The improvement in image quality and diagnostic accuracy of the technique was assessed in simultaneous18F-FDG PET/MR scans of a canine model of myocardial infarct and was demonstrated in a human subject.Results:MR motion fields were successfully used to compensate for in vivo cardiac motion, leading to improvements in full width at half maximum of the canine myocardium of 13% ± 5%, similar to cardiac gating but with a 90% ± 57% higher contrast-to-noise ratio between myocardium and blood. Motion correction led to an improvement in MR image quality in all subjects, with an increase in sharpness of the canine coronary arteries of 85% ± 72%. A functional assessment showed good agreement with standard MR cine scans with a difference in ejection fraction of -2% ± 3%. MR-based respiratory and cardiac motion information was used to improve the PET image quality of a human in vivo scan.Conclusion:The MR technique presented here provides both diagnostic and motion information that can be used to improve MR and PET image quality. Reliable respiratory and cardiac motion correction could make cardiac PET results more reproducible.
King's College London, Division of Imaging Sciences and Biomedical Engineering, London, United Kingdom christoph.kolbitsch@ptb.de.|Physikalisch-Technische Bundesanstalt (PTB), Berlin, Germany.
Christoph
C
Kolbitsch
National Institutes of Health, Clinical Center, Radiology and Imaging Sciences, Bethesda, Maryland; and.
Mark A
MA
Ahlman
National Institutes of Health, Clinical Center, Radiology and Imaging Sciences, Bethesda, Maryland; and.
Cynthia
C
Davies-Venn
National Institutes of Health, Clinical Center, Radiology and Imaging Sciences, Bethesda, Maryland; and.
Robert
R
Evers
National Institutes of Health, National Heart, Lung, and Blood Institute, Bethesda, Maryland.
Michael
M
Hansen
King's College London, Division of Imaging Sciences and Biomedical Engineering, London, United Kingdom.
Devis
D
Peressutti
King's College London, Division of Imaging Sciences and Biomedical Engineering, London, United Kingdom.
Paul
P
Marsden
National Institutes of Health, National Heart, Lung, and Blood Institute, Bethesda, Maryland.
Peter
P
Kellman
National Institutes of Health, Clinical Center, Radiology and Imaging Sciences, Bethesda, Maryland; and.
David A
DA
Bluemke
King's College London, Division of Imaging Sciences and Biomedical Engineering, London, United Kingdom.|Physikalisch-Technische Bundesanstalt (PTB), Berlin, Germany.
Tobias
T
Schaeffter
D000465:Algorithms; D000818:Animals; D055424:Cardiac-Gated Imaging Techniques / Q000379:methods*; D004285:Dogs; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D064847:Multimodal Imaging / Q000379:methods; D009203:Myocardial Infarction / Q000000981:diagnostic imaging*; D049268:Positron-Emission Tomography / Q000379:methods*; D015203:Reproducibility of Results; D055425:Respiratory-Gated Imaging Techniques / Q000379:methods*; D012680:Sensitivity and Specificity
cardiac PET; cardiac and respiratory motion; motion compensation; radial phase encoding; simultaneous PET/MR