title: Simplified Bernoulli's method significantly underestimates pulmonary transvalvular pressure drop.
abstract: To determine whether neglecting the flow unsteadiness in simplified Bernoulli's equation significantly affects the pulmonary transvalvular pressure drop estimation.
  
  
  
  3.0T magnetic resonance imaging (MRI) 4D velocity mapping was performed on four healthy volunteers, seven patients with repaired tetralogy of Fallot, and thirteen patients with transposition of the great arteries repaired by arterial switch. Pulmonary transvalvular pressure drop was estimated based on two methods: General Bernoulli's Equation (GBE), ie, the most complete form; and Simplified Bernoulli's Equation (SBE), known as 4V(2) . More than 2300 individual pressure drop measurements were used to compare the simplified and the general Bernoulli's methods. A linear mixed-effects model was employed for statistical analyses, fully accounting for clustering of observations among the methods and systolic phases.
  
  
  
  The simplified Bernoulli's method systematically underestimated the pressure drop compared to general Bernoulli's method during the entire systolic phase (P < 0.05), including the peak systole, where on average ΔpSBE/ΔpGBE=78%.
  
  
  
  The simplified Bernoulli method underestimated the pressure drop during all systolic phases in all the studied subjects. Therefore, it is necessary to take into account the flow unsteadiness for more accurate estimation of the pressure drop. J. Magn. Reson. Imaging 2016;43:1313-1319.
authors.affiliation: University of California Irvine, Department of Biomedical Engineering, Edwards Lifesciences Center of Advanced Cardiovascular Technology, Irvine, California, USA.
authors.forename: Ahmad
authors.initials: A
authors.lastname: Falahatpisheh
authors.affiliation: University Hospital Schleswig-Holstein Campus Kiel, Department of Pediatric Cardiology, Kiel, Germany.
authors.forename: Carsten
authors.initials: C
authors.lastname: Rickers
authors.affiliation: University Hospital Schleswig-Holstein Campus Kiel, Department of Pediatric Cardiology, Kiel, Germany.
authors.forename: Dominik
authors.initials: D
authors.lastname: Gabbert
authors.affiliation: Royal Brompton Hospital, London, UK, NIHR Cardiovascular Biomedical Research Unit of Royal Brompton and Harefield NHS Foundation Trust and Imperial College, London, UK.
authors.forename: Ee Ling
authors.initials: EL
authors.lastname: Heng
authors.affiliation: Siemens Healthcare, Erlangen, Germany.
authors.forename: Aurelien
authors.initials: A
authors.lastname: Stalder
authors.affiliation: University Hospital Schleswig-Holstein Campus Kiel, Department of Pediatric Cardiology, Kiel, Germany.
authors.forename: Hans-Heiner
authors.initials: HH
authors.lastname: Kramer
authors.affiliation: Royal Brompton Hospital, London, UK, NIHR Cardiovascular Biomedical Research Unit of Royal Brompton and Harefield NHS Foundation Trust and Imperial College, London, UK.
authors.forename: Philip J
authors.initials: PJ
authors.lastname: Kilner
authors.affiliation: University of California Irvine, Department of Biomedical Engineering, Edwards Lifesciences Center of Advanced Cardiovascular Technology, Irvine, California, USA.
authors.forename: Arash
authors.initials: A
authors.lastname: Kheradvar
mesh_terms: D000293:Adolescent; D000328:Adult; D001783:Blood Flow Velocity; D001794:Blood Pressure; D001795:Blood Pressure Determination / Q000379:methods*; D002648:Child; D003198:Computer Simulation; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D007223:Infant; D019028:Magnetic Resonance Imaging, Cine / Q000379:methods*; D008297:Male; D008875:Middle Aged; D008955:Models, Cardiovascular; D011652:Pulmonary Circulation; D011664:Pulmonary Valve / Q000000981:diagnostic imaging / Q000503:physiopathology*; D011666:Pulmonary Valve Stenosis / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D055815:Young Adult
keywords: Bernoulli equation; pulmonary transvalvular pressure drop; pulmonary valve stenosis; unsteady Bernoulli equation