title: Real-time phase-contrast flow MRI of haemodynamic changes in the ascending aorta and superior vena cava during Mueller manoeuvre.
abstract: OBJECTIVE
  To evaluate the potential of real-time phase-contrast flow magnetic resonance imaging (MRI) at 40 ms resolution for the simultaneous determination of blood flow in the ascending aorta (AA) and superior vena cava (SVC) in response to reduced intrathoracic pressure (Mueller manoeuvre).
  
  
  METHODS
  Through-plane flow was assessed in 20 healthy young subjects using real-time phase-contrast MRI based on highly undersampled radial fast low-angle shot (FLASH) with image reconstruction by regularized non-linear inversion. Haemodynamic alterations (three repetitions per subject = 60 events) were evaluated during normal breathing (10 s), inhalation with nearly closed epiglottis (10 s), and recovery (20 s).
  
  
  RESULTS
  Relative to normal breathing and despite interindividual differences, reduced intrathoracic pressure by at least 30 mmHg significantly decreased the initial peak mean velocity (averaged across the lumen) in the AA by -24 ± 9% and increased the velocity in the SVC by +28 ± 25% (p < 0.0001, n = 23 successful events). Respective changes in flow volume per heartbeat were -25 ± 9% in the AA and +49 ± 44% in the SVC (p < 0.0001, n = 23). Flow parameters returned to baseline during sustained pressure reduction, while the heart rate was elevated by 10% (p < 0.0001) after the start (n = 24) and end (n = 17) of the manoeuvre.
  
  
  CONCLUSIONS
  Real-time flow MRI during low intrathoracic pressure non-invasively revealed quantitative haemodynamic adjustments in both the AA and SVC.
authors: Institute for Diagnostic and Interventional Radiology, Heart Centre, University Medical Centre, Georg-August-University Göttingen, Germany; DZHK, German Centre for Cardiovascular Research, Göttingen, Germany.
authors: M
authors: M
authors: Fasshauer
authors: Biomedizinische NMR Forschungs GmbH am Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany; DZHK, German Centre for Cardiovascular Research, Göttingen, Germany.
authors: A A
authors: AA
authors: Joseph
authors: Institute for Diagnostic and Interventional Radiology, Heart Centre, University Medical Centre, Georg-August-University Göttingen, Germany; DZHK, German Centre for Cardiovascular Research, Göttingen, Germany.
authors: J T
authors: JT
authors: Kowallick
authors: Institute for Diagnostic and Interventional Radiology, Heart Centre, University Medical Centre, Georg-August-University Göttingen, Germany; Clinic for Cardiology and Pneumology, Heart Centre, University Medical Centre, Georg-August-University Göttingen, Germany; DZHK, German Centre for Cardiovascular Research, Göttingen, Germany.
authors: C
authors: C
authors: Unterberg-Buchwald
authors: Biomedizinische NMR Forschungs GmbH am Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany; DZHK, German Centre for Cardiovascular Research, Göttingen, Germany.
authors: K D
authors: KD
authors: Merboldt
authors: Biomedizinische NMR Forschungs GmbH am Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany; DZHK, German Centre for Cardiovascular Research, Göttingen, Germany.
authors: D
authors: D
authors: Voit
authors: DZHK, German Centre for Cardiovascular Research, Göttingen, Germany; Clinic for Paediatric Cardiology and Intensive Care Medicine, Heart Centre, University Medical Centre, Georg-August-University Göttingen, Germany.
authors: M
authors: M
authors: Steinmetz
authors: Institute for Diagnostic and Interventional Radiology, Heart Centre, University Medical Centre, Georg-August-University Göttingen, Germany; DZHK, German Centre for Cardiovascular Research, Göttingen, Germany.
authors: W
authors: W
authors: Staab
authors: Biomedizinische NMR Forschungs GmbH am Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany; DZHK, German Centre for Cardiovascular Research, Göttingen, Germany.
authors: S
authors: S
authors: Schaetz
authors: Biomedizinische NMR Forschungs GmbH am Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany; DZHK, German Centre for Cardiovascular Research, Göttingen, Germany.
authors: S
authors: S
authors: Zhang
authors: Biomedizinische NMR Forschungs GmbH am Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany; DZHK, German Centre for Cardiovascular Research, Göttingen, Germany.
authors: J
authors: J
authors: Frahm
authors: Institute for Diagnostic and Interventional Radiology, Heart Centre, University Medical Centre, Georg-August-University Göttingen, Germany; DZHK, German Centre for Cardiovascular Research, Göttingen, Germany. Electronic address: Joachim.lotz@med.uni-goettingen.de.
authors: J
authors: J
authors: Lotz
authors: Institute for Diagnostic and Interventional Radiology, Heart Centre, University Medical Centre, Georg-August-University Göttingen, Germany; DZHK, German Centre for Cardiovascular Research, Göttingen, Germany.
authors: J M
authors: JM
authors: Sohns
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D001011:Aorta / Q000502:physiology*; D001783:Blood Flow Velocity / Q000502:physiology; D001794:Blood Pressure / Q000502:physiology; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006439:Hemodynamics / Q000502:physiology*; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D001239:Inhalation / Q000502:physiology; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D011652:Pulmonary Circulation / Q000502:physiology*; D012016:Reference Values; D015656:Respiratory Mechanics / Q000502:physiology*; D013318:Stroke Volume / Q000502:physiology; D014683:Vena Cava, Superior / Q000502:physiology*