Author + information
- Received June 24, 1994
- Revision received September 22, 1994
- Accepted September 28, 1994
- Published online March 1, 1995.
- Kunio Miyatake, MD, FACCa,b,*,
- Masakazu Yamagishi, MDa,b,
- Norio Tanaka, BSa,b,
- Masaaki Uematsu, MDa,b,
- Nobuo Yamazaki, MSa,b,
- Yoshitake Mine, MSa,b,
- Akihiro Sano, MSa,b and
- Makoto Hirama, PhDa,b
- ↵*Address for correspondence: Dr. Kunio Miyatake, Cardiology Division of Medicine, National Cardiovascular Center, 5-7-1, Fujishiro-dai, Suita, Osaka 565, Japan.
Objectives. 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.
This study was supported in part by Research Grant for Cardiovascular Disease 5A-3 from the Ministry of Health and Welfare of Japan, Tokyo, in 1993. It was presented in part at the 66th Annual Scientific Sessions of the American Heart Association, Atlanta, Georgia, November 1993.
- Received June 24, 1994.
- Revision received September 22, 1994.
- Accepted September 28, 1994.
- American College of Cardiology