An investigation has been carried out on the velocity resolution, spat
ial resolution and accuracy of Doppler images as part of a study into
the Doppler display of cardiac tissue motion. Test-phantoms were desig
ned to perform this work and images were captured on a computer. The c
haracteristics of the phantom images and of the image capture process
were studied. The smallest detail that was observed in the Doppler ima
ge was 3 mm by 3 mm. Doppler receive gain and Doppler ensemble size bo
th affected velocity resolution. Different target materials gave diffe
rent measures for velocity resolution. This could be related to the di
fferent back-scatter intensities of the materials.