title: Higher dose dobutamine stress MR imaging in repaired Tetralogy of Fallot: observer variance of volumetric assessment compared with normal volunteers.
abstract: OBJECTIVE
  To investigate changes in image quality and observer variance between rest and higher-dose dobutamine stress MR imaging (DS-MR) in tetralogy of Fallot (TOF) patients and in a group of normal healthy volunteers using both axial and short axis orientation for cardiac volumetric assessment.
  
  
  METHODS
  Eighteen adult patients (age 34 ± 13) with TOF and severe pulmonary regurgitation and 10 healthy volunteers underwent ventricular MR volumetry at baseline and during dobutamine infusion of 10 μg/kg/min and 20 μg/kg/min. Inter-observer and intra-observer agreement was calculated by coefficient of variance (COV).
  
  
  RESULTS
  Inter-observer comparison showed good agreement for left ventricle (LV) and right ventricle (RV) end-diastolic volumes at rest and both stress levels in TOF patients (axial geometry) and in normal volunteers (short axis). During dobutamine stress, the COV in TOF patients increased for LV end-systolic volume (LV-ESV) with each level, suggesting less agreement between observers. In contrast, RV-ESV was much more comparable with a COV < 10 at each condition. All volumetric measurements in normal volunteers showed good inter-observer agreement. Excellent intra-observer agreement could be seen for all volumetric parameters with COV levels below 7.
  
  
  CONCLUSIONS
  Volumetric assessment during DS-MR shows excellent inter-observer agreement, except for LV-ESV in the TOF patients at higher doses of dobutamine. The axial geometry appears to be reproducible for assessment of RV parameters, and could be considered superior to short axis imaging in patients with repaired TOF.
authors.affiliation: King's College London BHF Centre, Division of Imaging Sciences, NIHR Biomedical Research Centre at Guy's and St Thomas' NHS Foundation Trust, London, UK; Adult Congenital Heart Disease Service, Guy's and St Thomas' NHS Foundation Trust, London, UK.
authors.forename: Victoria
authors.initials: V
authors.lastname: Parish
authors.forename: Israel
authors.initials: I
authors.lastname: Valverde
authors.forename: Shelby
authors.initials: S
authors.lastname: Kutty
authors.forename: Catherine
authors.initials: C
authors.lastname: Head
authors.forename: Gerald F
authors.initials: GF
authors.lastname: Greil
authors.forename: Tobias
authors.initials: T
authors.lastname: Schaeffter
authors.forename: Reza
authors.initials: R
authors.lastname: Razavi
authors.forename: Philipp
authors.initials: P
authors.lastname: Beerbaum
mesh_terms: D000328:Adult; D002316:Cardiotonic Agents / Q000008:administration & dosage; D004280:Dobutamine / Q000008:administration & dosage*; D004305:Dose-Response Relationship, Drug; D005080:Exercise Test / Q000379:methods*; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D015588:Observer Variation; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013771:Tetralogy of Fallot / Q000473:pathology* / Q000601:surgery*; D016896:Treatment Outcome
chemical_list: D002316:Cardiotonic Agents; D004280:Dobutamine
keywords: Dobutamine stress magnetic resonance imaging (DS-MR); Tetralogy of Fallot (TOF)