title: Impact of respiration on stroke volumes in paediatric controls and in patients after Fontan procedure assessed by MR real-time phase-velocity mapping.
abstract: OBJECTIVE
  Blood flow rate quantification using two-dimensional phase-contrast MRI (PC-MRI) results in averaging of flow information due to long acquisition times precluding the examination of short-term effects. The aim of this study was to determine respiration-related flow rate variations by non-electrocardiographic triggered real-time phase-contrast MRI (PC-MRI).
  
  
  RESULTS
  Real-time PC-MRI was applied to study respiration-driven blood flow fluctuations in the ascending aorta (AAo), superior vena cava (SVC), and inferior vena cava (IVC) under normal and forced breathing in 33 healthy children and 10 Fontan patients. Respiration-dependent flow rates were virtually generated by dividing the respiration curve into four segments: expiration, end-expiration, inspiration, and end-inspiration. Whereas in volunteers aortic flow rate was elevated during end-expiration (5.6 ± 3.0%) and decreased during end-inspiration (-5.8 ± 3.5%) in relation to mean blood flow (P < 0.05), highest flow was detected during inspiration in SVC (10.5 ± 14.1%) and IVC (22.5 ± 12.1%) and lowest flow during expiration (-11.6 ± 13.5%, -13.2 ± 14.1%, P < 0.05). Differences were increased under forced breathing in AAo (10.4 ± 5.5%, -7.4 ± 6.5%, P < 0.05) and SVC (40.0 ± 30.3%, -30.0 ± 19.2%, P < 0.05), whereas were unchanged in IVC (16.5 ± 23.6%, -13.7 ± 21.6%, P = n.s.). Regarding patients, respiratory-dependent flow rate variability was increased and had to be related to the patient's individual quality of Fontan circulation.
  
  
  CONCLUSIONS
  Real-time PC-MRI allows a physiological assessment of respiratory-related flow rate fluctuations in healthy subjects as well as in Fontan patients. Its capability for detection of short-term effects in clinical routine was demonstrated.
authors.affiliation: Institute for Radiology, Nuclear Medicine and Molecular Imaging, Heart and Diabetes Center Northrhine-Westfalia, Ruhr-University of Bochum, Georgstraße 11, D-32545 Bad Oeynhausen, Germany hkoerperich@hdz-nrw.de.
authors.forename: Hermann
authors.initials: H
authors.lastname: Körperich
authors.affiliation: Institute for Radiology, Nuclear Medicine and Molecular Imaging, Heart and Diabetes Center Northrhine-Westfalia, Ruhr-University of Bochum, Georgstraße 11, D-32545 Bad Oeynhausen, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Barth
authors.affiliation: Philips Healthcare, Hamburg, Germany.
authors.forename: Jürgen
authors.initials: J
authors.lastname: Gieseke
authors.affiliation: Center for Congenital Heart Defects, Heart and Diabetes Centre Northrhine-Westfalia, Ruhr-University of Bochum, Bad Oeynhausen, Germany.
authors.forename: Katja
authors.initials: K
authors.lastname: Müller
authors.affiliation: Institute for Radiology, Nuclear Medicine and Molecular Imaging, Heart and Diabetes Center Northrhine-Westfalia, Ruhr-University of Bochum, Georgstraße 11, D-32545 Bad Oeynhausen, Germany.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Burchert
authors.affiliation: Institute for Radiology, Nuclear Medicine and Molecular Imaging, Heart and Diabetes Center Northrhine-Westfalia, Ruhr-University of Bochum, Georgstraße 11, D-32545 Bad Oeynhausen, Germany.
authors.forename: Hermann
authors.initials: H
authors.lastname: Esdorn
authors.affiliation: Center for Congenital Heart Defects, Heart and Diabetes Centre Northrhine-Westfalia, Ruhr-University of Bochum, Bad Oeynhausen, Germany.
authors.forename: Deniz
authors.initials: D
authors.lastname: Kececioglu
authors.affiliation: Medizinische Hochschule Hannover, Kinderheilkunde, Pädiatrische Kardiologie und Pädiatrische Intensivmedizin, Hannover, Germany.
authors.forename: Philipp
authors.initials: P
authors.lastname: Beerbaum
authors.affiliation: Center for Congenital Heart Defects, Heart and Diabetes Centre Northrhine-Westfalia, Ruhr-University of Bochum, Bad Oeynhausen, Germany.
authors.forename: Kai Thorsten
authors.initials: KT
authors.lastname: Laser
mesh_terms: D000293:Adolescent; D001783:Blood Flow Velocity / Q000502:physiology*; D055424:Cardiac-Gated Imaging Techniques; D016022:Case-Control Studies; D002648:Child; D004452:Echocardiography; D005260:Female; D018729:Fontan Procedure; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D011446:Prospective Studies; D012119:Respiration; D013318:Stroke Volume / Q000502:physiology*; D055815:Young Adult
keywords: MRI; Pediatrics; Phase-velocity mapping; Respiration-dependency; Stroke volume