title: Semi-automated analysis of color M-mode echocardiographic images for determining transmitral pressure gradients using a simplified Euler equation.
abstract: We hypothesize that a simplified version of the Euler equation (SEE) utilizing differences in velocity over a distance and time as obtained by Color Doppler M-mode (CMM) echocardiography can approximate actual peak transmitral pressure gradients deltaP(TM).
  
  
  METHODS
  In 14 patients undergoing open-heart surgery, deltaP(TM) was measured under various hemodynamic conditions using 2 high fidelity transducers, 5 cm apart. Transesophageal CMM images were simultaneously acquired and a customized image analysis application was used to abstract spatiotemporal velocity characteristics. Using both the SEE and a simplified Bernoulli equations, deltaP(TM) were determined and compared to the actual deltaP(TM).
  
  
  RESULTS
  While the simplified Bernoulli equation resulted in a poor estimate (y=0.075x+0.71, r=0.45), the deltaP(TM) obtained using the SEE correlated strongly (y=0.79x+0.48, r=0.91) with the actual measurements.
  
  
  CONCLUSIONS
  Semi-automated analysis of CMM images using a SEE can accurately estimate actual deltaP(TM).
authors.affiliation: The Cardiovascular Imaging Center, The Cleveland Clinic Foundation, Cleveland, Ohio, USA.
authors.forename: M S
authors.initials: MS
authors.lastname: Firstenberg
authors.forename: N L
authors.initials: NL
authors.lastname: Greenberg
authors.forename: M J
authors.initials: MJ
authors.lastname: Garcia
authors.forename: P L
authors.initials: PL
authors.lastname: Castro
authors.forename: D L
authors.initials: DL
authors.lastname: Prior
authors.forename: N G
authors.initials: NG
authors.lastname: Smedira
authors.forename: J D
authors.initials: JD
authors.lastname: Thomas
mesh_terms: D000465:Algorithms; D001331:Automation; D001783:Blood Flow Velocity / Q000502:physiology; D003326:Coronary Circulation / Q000502:physiology*; D018618:Echocardiography, Doppler, Color; D017548:Echocardiography, Transesophageal; D006439:Hemodynamics; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008943:Mitral Valve / Q000502:physiology*; D011312:Pressure; D014160:Transducers, Pressure