title: Four-dimensional computed tomography: a method of assessing right ventricular outflow tract and pulmonary artery deformations throughout the cardiac cycle.
abstract: OBJECTIVE
  To characterise 3D deformations of the right ventricular outflow tract (RVOT)/pulmonary arteries (PAs) during the cardiac cycle and estimate the errors of conventional 2D assessments.
  
  
  METHODS
  Contrast-enhanced, ECG-gated cardiovascular computed tomography (CT) findings were retrospectively analysed from 12 patients. The acquisition of 3D images over 10 phases of the cardiac cycle created a four-dimensional CT (4DCT) dataset. The datasets were reconstructed and deformation measured at various levels of the RVOT/PAs in both space and time. Section planes were either static or dynamic relative to the motion of the structures.
  
  
  RESULTS
  4DCT enabled measurement and characterisation of in vivo 3D changes of patients' RVOT/PA during the cardiac cycle. The studied patient population showed a wide range of RVOT/PA morphologies, sizes and dynamics that develop late after surgical repair of congenital heart disease. There were also significant differences in the measured cross-sectional areas of the structures between static and dynamic section planes (up to 150%, p<0.05) secondary to large 3D displacements and rotations.
  
  
  CONCLUSIONS
  4DCT imaging data suggest high variability in RVOT/PA dynamics and significant errors in deformation measurements if 3D analysis is not carried out. These findings play an important role for the development of novel percutaneous approaches to pulmonary valve intervention.
authors.affiliation: Cardiovascular Unit, UCL Institute of Child Health & Great Ormond Street Hospital for Children, Great Ormond Street, London, WC1N 3JH, UK. s.schievano@ich.ucl.ac.uk
authors.forename: Silvia
authors.initials: S
authors.lastname: Schievano
authors.forename: Claudio
authors.initials: C
authors.lastname: Capelli
authors.forename: Carol
authors.initials: C
authors.lastname: Young
authors.forename: Philipp
authors.initials: P
authors.lastname: Lurz
authors.forename: Johannes
authors.initials: J
authors.lastname: Nordmeyer
authors.forename: Catherine
authors.initials: C
authors.lastname: Owens
authors.forename: Philipp
authors.initials: P
authors.lastname: Bonhoeffer
authors.forename: Andrew M
authors.initials: AM
authors.lastname: Taylor
mesh_terms: D000328:Adult; D000368:Aged; D002648:Child; D002675:Child, Preschool; D003287:Contrast Media; D005260:Female; D056973:Four-Dimensional Computed Tomography / Q000379:methods; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D011651:Pulmonary Artery / Q000002:abnormalities / Q000000981:diagnostic imaging; D012189:Retrospective Studies; D014694:Ventricular Outflow Obstruction / Q000175:diagnosis* / Q000000981:diagnostic imaging; D055815:Young Adult
chemical_list: D003287:Contrast Media