title: Automated flow quantification in valvular heart disease based on backscattered Doppler power analysis: implementation on matrix-array ultrasound imaging systems.
abstract: OBJECTIVE
  Cardiac ultrasound imaging systems are limited in the noninvasive quantification of valvular regurgitation due to indirect measurements and inaccurate hemodynamic assumptions. We recently demonstrated that the principle of integration of backscattered acoustic Doppler power times velocity can be used for flow quantification in valvular regurgitation directly at the vena contracta of a regurgitant flow jet. We now aimed to accomplish implementation of automated Doppler power flow analysis software on a standard cardiac ultrasound system utilizing novel matrix-array transducer technology with detailed description of system requirements, components and software contributing to the system.
  
  
  METHODS
  This system based on a 3.5 MHz, matrix-array cardiac ultrasound scanner (Sonos 5500, Philips Medical Systems) was validated by means of comprehensive experimental signal generator trials, in vitro flow phantom trials and in vivo testing in 48 patients with mitral regurgitation of different severity and etiology using magnetic resonance imaging (MRI) for reference.
  
  
  RESULTS
  All measurements displayed good correlation to the reference values, indicating successful implementation of automated Doppler power flow analysis on a matrix-array ultrasound imaging system. Systematic underestimation of effective regurgitant orifice areas >0.65 cm(2) and volumes >40 ml was found due to currently limited Doppler beam width that could be readily overcome by the use of new generation 2D matrix-array technology.
  
  
  CONCLUSIONS
  Automated flow quantification in valvular heart disease based on backscattered Doppler power can be fully implemented on board a routinely used matrix-array ultrasound imaging systems. Such automated Doppler power flow analysis of valvular regurgitant flow directly, noninvasively, and user independent overcomes the practical limitations of current techniques.
authors.affiliation: West German Heart Center Essen, Department of Cardiology, University of Duisburg-Essen, Hufelandstrasse 55, 45122 Essen, Germany. thomas.buck@uk-essen.de
authors.forename: Thomas
authors.initials: T
authors.lastname: Buck
authors.forename: Shawn M
authors.initials: SM
authors.lastname: Hwang
authors.forename: Björn
authors.initials: B
authors.lastname: Plicht
authors.forename: Ronald A
authors.initials: RA
authors.lastname: Mucci
authors.forename: Peter
authors.initials: P
authors.lastname: Hunold
authors.forename: Raimund
authors.initials: R
authors.lastname: Erbel
authors.forename: Robert A
authors.initials: RA
authors.lastname: Levine
mesh_terms: D000328:Adult; D000368:Aged; D001331:Automation; D003326:Coronary Circulation; D015150:Echocardiography, Doppler / Q000295:instrumentation*; D004867:Equipment Design; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D008944:Mitral Valve Insufficiency / Q000000981:diagnostic imaging* / Q000473:pathology / Q000503:physiopathology; D008955:Models, Cardiovascular; D019047:Phantoms, Imaging; D015203:Reproducibility of Results; D012720:Severity of Illness Index; D012984:Software; D014159:Transducers