New contrast-detail phantoms for improved precision in lesion detection measurements.

The previous design of our ultrasound contrast-detail (C-D) phantom is limited in its ability to evaluate the quality of diagnostic ultrasound imaging systems. There is uncertainty in the contrast-detail measurements due to the single available viewing angle for each target and the resulting single realization of the ultrasound speckle pattern. Two new contrast-detail phantom designs are described which enable many independent realizations of the speckle noise for observer C-D experiments of improved precision. In the first design, a single tissue-mimicking cone is located on the axis of a tissue-mimicking cylinder. Cross-sectional images of the cone which simulate focal lesions can be obtained from any orientation by rotating the cylinder under the transducer. In the second new design, a tissue-mimicking cone is positioned in a tissue-mimicking slurry of agar/graphite spheres. Gentle stirring of the slurry and rotation of the cone produce many independent realizations of the speckle. In both new phantoms, the lesion contrast can be specified and is frequency/transducer independent.