title: Event-by-Event Continuous Respiratory Motion Correction for Dynamic PET Imaging.
abstract: Existing respiratory motion-correction methods are applied only to static PET imaging. We have previously developed an event-by-event respiratory motion-correction method with correlations between internal organ motion and external respiratory signals (INTEX). This method is uniquely appropriate for dynamic imaging because it corrects motion for each time point. In this study, we applied INTEX to human dynamic PET studies with various tracers and investigated the impact on kinetic parameter estimation.
  
  
  
  The use of 3 tracers-a myocardial perfusion tracer, (82)Rb (n = 7); a pancreatic β-cell tracer, (18)F-FP(+)DTBZ (n = 4); and a tumor hypoxia tracer, (18)F-fluoromisonidazole ((18)F-FMISO) (n = 1)-was investigated in a study of 12 human subjects. Both rest and stress studies were performed for (82)Rb. The Anzai belt system was used to record respiratory motion. Three-dimensional internal organ motion in high temporal resolution was calculated by INTEX to guide event-by-event respiratory motion correction of target organs in each dynamic frame. Time-activity curves of regions of interest drawn based on end-expiration PET images were obtained. For (82)Rb studies, K1 was obtained with a 1-tissue model using a left-ventricle input function. Rest-stress myocardial blood flow (MBF) and coronary flow reserve (CFR) were determined. For (18)F-FP(+)DTBZ studies, the total volume of distribution was estimated with arterial input functions using the multilinear analysis 1 method. For the (18)F-FMISO study, the net uptake rate Ki was obtained with a 2-tissue irreversible model using a left-ventricle input function. All parameters were compared with the values derived without motion correction.
  
  
  
  With INTEX, K1 and MBF increased by 10% ± 12% and 15% ± 19%, respectively, for (82)Rb stress studies. CFR increased by 19% ± 21%. For studies with motion amplitudes greater than 8 mm (n = 3), K1, MBF, and CFR increased by 20% ± 12%, 30% ± 20%, and 34% ± 23%, respectively. For (82)Rb rest studies, INTEX had minimal effect on parameter estimation. The total volume of distribution of (18)F-FP(+)DTBZ and Ki of (18)F-FMISO increased by 17% ± 6% and 20%, respectively.
  
  
  
  Respiratory motion can have a substantial impact on dynamic PET in the thorax and abdomen. The INTEX method using continuous external motion data substantially changed parameters in kinetic modeling. More accurate estimation is expected with INTEX.
authors.affiliation: Department of Diagnostic Radiology, Yale University, New Haven, Connecticut Department of Engineering Physics, Key Laboratory of Particle and Radiation Imaging (Tsinghua University), Ministry of Education, Beijing, China.
authors.forename: Yunhan
authors.initials: Y
authors.lastname: Yu
authors.affiliation: Department of Diagnostic Radiology, Yale University, New Haven, Connecticut.
authors.forename: Chung
authors.initials: C
authors.lastname: Chan
authors.affiliation: Department of Engineering Physics, Key Laboratory of Particle and Radiation Imaging (Tsinghua University), Ministry of Education, Beijing, China.
authors.forename: Tianyu
authors.initials: T
authors.lastname: Ma
authors.affiliation: Department of Engineering Physics, Key Laboratory of Particle and Radiation Imaging (Tsinghua University), Ministry of Education, Beijing, China.
authors.forename: Yaqiang
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Department of Diagnostic Radiology, Yale University, New Haven, Connecticut.
authors.forename: Jean-Dominique
authors.initials: JD
authors.lastname: Gallezot
authors.affiliation: Department of Diagnostic Radiology, Yale University, New Haven, Connecticut.
authors.forename: Mika
authors.initials: M
authors.lastname: Naganawa
authors.affiliation: Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, Connecticut Department of Medical Physics in Radiation Oncology, German Cancer Research Center, Heidelberg, Germany.
authors.forename: Olivia J
authors.initials: OJ
authors.lastname: Kelada
authors.affiliation: Department of Biomedical Engineering, Yale University School of Medicine, New Haven, Connecticut; and.
authors.forename: Mary
authors.initials: M
authors.lastname: Germino
authors.affiliation: Department of Diagnostic Radiology, Yale University, New Haven, Connecticut Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut.
authors.forename: Albert J
authors.initials: AJ
authors.lastname: Sinusas
authors.affiliation: Department of Diagnostic Radiology, Yale University, New Haven, Connecticut Department of Biomedical Engineering, Yale University School of Medicine, New Haven, Connecticut; and.
authors.forename: Richard E
authors.initials: RE
authors.lastname: Carson
authors.affiliation: Department of Diagnostic Radiology, Yale University, New Haven, Connecticut Department of Biomedical Engineering, Yale University School of Medicine, New Haven, Connecticut; and chi.liu@yale.edu.
authors.forename: Chi
authors.initials: C
authors.lastname: Liu
mesh_terms: D000328:Adult; D000368:Aged; D003326:Coronary Circulation; D005080:Exercise Test; D005260:Female; D006331:Heart Diseases / Q000000981:diagnostic imaging; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D050417:Insulin-Secreting Cells; D008297:Male; D008920:Misonidazole / Q000031:analogs & derivatives; D015233:Models, Statistical; D009038:Motion; D049268:Positron-Emission Tomography / Q000379:methods*; D019275:Radiopharmaceuticals; D015656:Respiratory Mechanics; D012146:Rest; D012414:Rubidium Radioisotopes; D055815:Young Adult
chemical_list: D019275:Radiopharmaceuticals; D012414:Rubidium Radioisotopes; C031843:fluoromisonidazole; D008920:Misonidazole
keywords: INTEX; dynamic PET imaging; respiratory motion correction