A comparison of regional myocardial velocity information derived by pulsedand color Doppler techniques: An in vitro and in vivo study

The objective was to compare velocity information derived from either a tis sue mimicking phantom or normal contracting myocardium by both pulsed wave and color Doppler myocardial imaging (PWDMI and CDMI). Both CDMI and PWDMI allow quantitative assessment of regional myocardial contraction and relaxa tion velocities, but their potential clinical applications have not yet bee n investigated. Moreover, no information is available as to whether they ca n be used interchangeably for regional velocity assessment. For the in vitr o study, a rotating, circular-shaped, tissue-mimicking sponge driven by a m otor at speeds of 15, 30, 60, 90 rpm was used to derive velocity data from the same eight points of interest by using PWDMI or CDMI techniques. For th e in vivo study, 25 normal subjects were examined at rest using parasternal and apical approaches. Velocity profiles were derived from the same 26 are as of interest (18 left ventricular segments, 3 right ventricular segments, and 5 measurement points for the tricuspid and mitral annuli) for each tec hnique. Peak maximal velocities were detected by PWDMI and peak mean veloci ties were measured using CDMI. The results of the in vitro study phantom sh owed excellent correlation (r = 0.99, P < 0.001) and satisfactory agreement (0.04 cm/sec; 3.3 cm/sec) between both Doppler techniques. PWDMI velocitie s were higher than CDMI velocities by up to 20% and overestimated the real velocity value (0.37 +/- 0.29 cm/sec) while CDMI underestimated predicted v elocity by 1.35 +/- 0.36 cm/sec. Good correlation (r = 0.87, P < 0.001), bu t poor agreement (-2.1 cm/sec; 5.4 cm/sec) was shown in vivo for all segmen ts with regard to peak systolic and diastolic velocities. Both Doppler tech niques cannot be used interchangeably for comparing peak velocities in, the clinical situation. However, with adequate temporal resolution, they can b e used interchangeably for velocity profile recording and for timing of eve nts.