title: Self-gated MRI motion modeling for respiratory motion compensation in integrated PET/MRI.
abstract: Accurate localization and uptake quantification of lesions in the chest and abdomen using PET imaging is challenged by respiratory motion occurring during the exam. This work describes how a stack-of-stars MRI acquisition on integrated PET/MRI systems can be used to derive a high-resolution motion model, how many respiratory phases need to be differentiated, how much MRI scan time is required, and how the model is employed for motion-corrected PET reconstruction. MRI self-gating is applied to perform respiratory gating of the MRI data and simultaneously acquired PET raw data. After gated PET reconstruction, the MRI motion model is used to fuse the individual gates into a single, motion-compensated volume with high signal-to-noise ratio (SNR). The proposed method is evaluated in vivo for 15 clinical patients. The gating requires 5-7 bins to capture the motion to an average accuracy of 2mm. With 5 bins, the motion-modeling scan can be shortened to 3-4 min. The motion-compensated reconstructions show significantly higher accuracy in lesion quantification in terms of standardized uptake value (SUV) and different measures of lesion contrast compared to ungated PET reconstruction. Furthermore, unlike gated reconstructions, the motion-compensated reconstruction does not lead to SNR loss.
authors.affiliation: Pattern Recognition Lab, FAU Erlangen-Nürnberg, Erlangen, Germany; Siemens AG Healthcare MR, Erlangen, Germany. Electronic address: robertgrimm@siemens.com.
authors.forename: Robert
authors.initials: R
authors.lastname: Grimm
authors.affiliation: Department of Nuclear Medicine, Klinikum Rechts der Isar, Technische Universität München, Munich, Germany.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Fürst
authors.affiliation: Department of Nuclear Medicine, Klinikum Rechts der Isar, Technische Universität München, Munich, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Souvatzoglou
authors.affiliation: Pattern Recognition Lab, FAU Erlangen-Nürnberg, Erlangen, Germany; Siemens AG Healthcare MR, Erlangen, Germany.
authors.forename: Christoph
authors.initials: C
authors.lastname: Forman
authors.affiliation: Pattern Recognition Lab, FAU Erlangen-Nürnberg, Erlangen, Germany.
authors.forename: Jana
authors.initials: J
authors.lastname: Hutter
authors.affiliation: Department of Nuclear Medicine, Klinikum Rechts der Isar, Technische Universität München, Munich, Germany.
authors.forename: Isabel
authors.initials: I
authors.lastname: Dregely
authors.affiliation: Department of Nuclear Medicine, Klinikum Rechts der Isar, Technische Universität München, Munich, Germany.
authors.forename: Sibylle I
authors.initials: SI
authors.lastname: Ziegler
authors.affiliation: Siemens AG Healthcare MR, Erlangen, Germany.
authors.forename: Berthold
authors.initials: B
authors.lastname: Kiefer
authors.affiliation: Pattern Recognition Lab, FAU Erlangen-Nürnberg, Erlangen, Germany.
authors.forename: Joachim
authors.initials: J
authors.lastname: Hornegger
authors.affiliation: Department of Radiology, NYU Langone Medical Center, New York, NY, USA.
authors.forename: Kai Tobias
authors.initials: KT
authors.lastname: Block
authors.affiliation: Department of Nuclear Medicine, Klinikum Rechts der Isar, Technische Universität München, Munich, Germany.
authors.forename: Stephan G
authors.initials: SG
authors.lastname: Nekolla
mesh_terms: D000008:Abdominal Neoplasms / Q000175:diagnosis*; D000465:Algorithms; D016477:Artifacts; D003198:Computer Simulation; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods*; D015233:Models, Statistical; D009038:Motion; D009068:Movement; D064847:Multimodal Imaging / Q000379:methods; D010363:Pattern Recognition, Automated / Q000379:methods; D049268:Positron-Emission Tomography / Q000379:methods*; D015203:Reproducibility of Results; D015656:Respiratory Mechanics; D055425:Respiratory-Gated Imaging Techniques / Q000379:methods*; D012680:Sensitivity and Specificity; D013382:Subtraction Technique; D018511:Systems Integration; D013899:Thoracic Neoplasms / Q000175:diagnosis*
keywords: MRI; Motion compensation; PET/MRI; Respiratory gating; Respiratory motion