title: New method for evaluating left ventricular wall motion by color-coded tissue Doppler imaging: in vitro and in vivo studies.
abstract: OBJECTIVE
  The aim of this study was to examine the accuracy and validity of a newly developed tissue Doppler imaging system in in vitro and in vivo studies.
  
  
  BACKGROUND
  Because quantitative measurement of wall motion velocity in real time is still difficult by conventional echocardiography, we developed a new system for evaluating ventricular wall motion by analyzing Doppler signals from cardiac tissue.
  
  
  METHODS
  We used a modified Doppler color imaging system, omitting the high pass filter to allow Doppler signals from cardiac tissue to enter the auto-correlator. Ultrasound carrier and pulse repetition frequencies were 3.75 MHz and 3.0 to 6.0 kHz, respectively. Under these conditions, the lowest measurable velocity was 0.2 cm/s.
  
  
  RESULTS
  In the rotating sponge model, the measured velocity correlated well with the actual velocity (y = 0.97x + 2.17, r = 0.99). In clinical settings, the mid-ejection mean velocity at either endocardial or epicardial sites of the left ventricular posterior wall measured by M-mode tissue Doppler imaging correlated well with that measured by conventional M-mode echocardiography (y = 0.94x + 0.64, r = 0.99). During systole, in healthy subjects, the anterior left ventricular wall was color-coded blue and the posterior wall was color-coded red, whereas the akinetic regions associated with myocardial infarction showed no color throughout the cardiac cycle. The ventricular posterior wall excursion velocity, defined as the difference between velocities at the endocardial and epicardial sites, was significantly slower in patients with dilated cardiomyopathy (0.4 +/- 0.3 cm/s) than in normal subjects (2.0 +/- 0.6 cm/s).
  
  
  CONCLUSIONS
  These results indicate that the present system accurately represents tissue velocity and can create two-dimensional color images that facilitate visual assessment of ventricular wall motion.
authors.affiliation: Cardiology Division of Medicine, National Cardiovascular Center, Osaka, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Miyatake
authors.forename: M
authors.initials: M
authors.lastname: Yamagishi
authors.forename: N
authors.initials: N
authors.lastname: Tanaka
authors.forename: M
authors.initials: M
authors.lastname: Uematsu
authors.forename: N
authors.initials: N
authors.lastname: Yamazaki
authors.forename: Y
authors.initials: Y
authors.lastname: Mine
authors.forename: A
authors.initials: A
authors.lastname: Sano
authors.forename: M
authors.initials: M
authors.lastname: Hirama
mesh_terms: D000328:Adult; D000368:Aged; D002311:Cardiomyopathy, Dilated / Q000000981:diagnostic imaging / Q000503:physiopathology; D015150:Echocardiography, Doppler; D005260:Female; D006331:Heart Diseases / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009200:Myocardial Contraction / Q000502:physiology*; D009203:Myocardial Infarction / Q000000981:diagnostic imaging / Q000503:physiopathology; D016277:Ventricular Function, Left / Q000502:physiology*