title: Quantification of atrial dynamics using cardiovascular magnetic resonance: inter-study reproducibility.
abstract: BACKGROUND
  Cardiovascular magnetic resonance (CMR) offers quantification of phasic atrial functions based on volumetric assessment and more recently, on CMR feature tracking (CMR-FT) quantitative strain and strain rate (SR) deformation imaging. Inter-study reproducibility is a key requirement for longitudinal studies but has not been defined for CMR-based quantification of left atrial (LA) and right atrial (RA) dynamics.
  
  
  METHODS
  Long-axis 2- and 4-chamber cine images were acquired at 9:00 (Exam A), 9:30 (Exam B) and 14:00 (Exam C) in 16 healthy volunteers. LA and RA reservoir, conduit and contractile booster pump functions were quantified by volumetric indexes as derived from fractional volume changes and by strain and SR as derived from CMR-FT. Exam A and B were compared to assess the inter-study reproducibility. Morning and afternoon scans were compared to address possible diurnal variation of atrial function.
  
  
  RESULTS
  Inter-study reproducibility was within acceptable limits for all LA and RA volumetric, strain and SR parameters. Inter-study reproducibility was better for volumetric indexes and strain than for SR parameters and better for LA than for RA dynamics. For the LA, reservoir function showed the best reproducibility (intraclass correlation coefficient (ICC) 0.94-0.97, coefficient of variation (CoV) 4.5-8.2%), followed by conduit (ICC 0.78-0.97, CoV 8.2-18.5%) and booster pump function (ICC 0.71-0.95, CoV 18.3-22.7). Similarly, for the RA, reproducibility was best for reservoir function (ICC 0.76-0.96, CoV 7.5-24.0%) followed by conduit (ICC 0.67-0.91, CoV 13.9-35.9) and booster pump function (ICC 0.73-0.90, CoV 19.4-32.3). Atrial dynamics were not measurably affected by diurnal variation between morning and afternoon scans.
  
  
  CONCLUSIONS
  Inter-study reproducibility for CMR-based derivation of LA and RA functions is acceptable using either volumetric, strain or SR parameters with LA function showing higher reproducibility than RA function assessment. Amongst the different functional components, reservoir function is most reproducibly assessed by either technique followed by conduit and booster pump function, which needs to be considered in future longitudinal research studies.
authors.affiliation: Division of Imaging Sciences and Biomedical Engineering, The Rayne Institute, St Thomas' Hospital, King's College London, London, UK. johannes.kowallick@kcl.ac.uk.|Institute for Diagnostic and Interventional Radiology, Georg-August-University Göttingen, Göttingen, Germany. johannes.kowallick@kcl.ac.uk.|DZHK (German Centre for Cardiovascular Research), partner site Göttingen, Göttingen, Germany. johannes.kowallick@kcl.ac.uk.
authors.forename: Johannes T
authors.initials: JT
authors.lastname: Kowallick
authors.affiliation: Portsmouth Hospitals NHS Trust, Portsmouth, UK. geraintmorton@gmail.com.
authors.forename: Geraint
authors.initials: G
authors.lastname: Morton
authors.affiliation: Division of Imaging Sciences and Biomedical Engineering, The Rayne Institute, St Thomas' Hospital, King's College London, London, UK. pablo.lamata@kcl.ac.uk.|Department of Computer Science, University of Oxford, Oxford, UK. pablo.lamata@kcl.ac.uk.
authors.forename: Pablo
authors.initials: P
authors.lastname: Lamata
authors.affiliation: Division of Imaging Sciences and Biomedical Engineering, The Rayne Institute, St Thomas' Hospital, King's College London, London, UK. roy.jogiya@kcl.ac.uk.
authors.forename: Roy
authors.initials: R
authors.lastname: Jogiya
authors.affiliation: Children's Hospital and Medical Center, University of Nebraska College of Medicine, Omaha, NE, USA. skutty@unmc.edu.
authors.forename: Shelby
authors.initials: S
authors.lastname: Kutty
authors.affiliation: Department of Cardiology and Pneumology, Georg-August-University Göttingen, Göttingen, Germany. hasenfus@med.uni-goettingen.de.|DZHK (German Centre for Cardiovascular Research), partner site Göttingen, Göttingen, Germany. hasenfus@med.uni-goettingen.de.
authors.forename: Gerd
authors.initials: G
authors.lastname: Hasenfuß
authors.affiliation: Institute for Diagnostic and Interventional Radiology, Georg-August-University Göttingen, Göttingen, Germany. joachim.lotz@med.uni-goettingen.de.|DZHK (German Centre for Cardiovascular Research), partner site Göttingen, Göttingen, Germany. joachim.lotz@med.uni-goettingen.de.
authors.forename: Joachim
authors.initials: J
authors.lastname: Lotz
authors.affiliation: Division of Imaging Sciences and Biomedical Engineering, The Rayne Institute, St Thomas' Hospital, King's College London, London, UK. eike.nagel@cardiac-imaging.org.|Division of Cardiovascular Imaging, Goethe University Frankfurt and German Centre for Cardiovascular Research (DZHK, partner site Rhine-Main), Frankfurt, Germany. eike.nagel@cardiac-imaging.org.
authors.forename: Eike
authors.initials: E
authors.lastname: Nagel
authors.affiliation: Division of Imaging Sciences and Biomedical Engineering, The Rayne Institute, St Thomas' Hospital, King's College London, London, UK. amedeo.chiribiri@kcl.ac.uk.
authors.forename: Amedeo
authors.initials: A
authors.lastname: Chiribiri
authors.affiliation: Division of Imaging Sciences and Biomedical Engineering, The Rayne Institute, St Thomas' Hospital, King's College London, London, UK. andreas_schuster@gmx.net.|Department of Cardiology and Pneumology, Georg-August-University Göttingen, Göttingen, Germany. andreas_schuster@gmx.net.|DZHK (German Centre for Cardiovascular Research), partner site Göttingen, Göttingen, Germany. andreas_schuster@gmx.net.
authors.forename: Andreas
authors.initials: A
authors.lastname: Schuster
mesh_terms: D000328:Adult; D016279:Atrial Function, Left; D016280:Atrial Function, Right; D001696:Biomechanical Phenomena; D002940:Circadian Rhythm; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D019028:Magnetic Resonance Imaging, Cine; D008297:Male; D009200:Myocardial Contraction; D015588:Observer Variation; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D013314:Stress, Mechanical; D013997:Time Factors; D055815:Young Adult