Spectral and color Doppler sonographic applications of a new test object with adjustable moving target spacing

A new test object has been developed with the aim of covering a wide range of Doppler quality assurance requirements, with particular emphasis on color Doppler imaging (both velocity and power modes). The test object consists of a rotating string-loop, which provides the single velocity source required for velocity calibration. The loop geometry provides two targets with adjustable spacing, which move in opposite directions within the same scan plane, and the string material offers a number of desirable properties (absence of knot artifacts, small diameter, uniform backscatter as a function of Doppler angle, and low attenuation). Representative results are included to demonstrate applications of the test object in the assessment of velocity accuracy, intrinsic spectral broadening, spatial resolution, and sensitivity, as well as to discuss quality assurance and performance issues in the context of spectral and color Doppler sonography.