Particle image-resolution test object.

A blur definition and measurement technique for high-subject-contrast image resolution is proposed. A new test object utilizing the blur principle has been developed and feasibility tested. In developing this new test object, tests of various sizes and concentrations of small plastic particles in a gelatin base were performed. Optimum particle sizes and concentrations were selected for the popular clinical transducer frequencies. Test images were obtained with static and real-time transducers of various focal properties. In all cases the proposed test object clearly indicated the zone (focal zone) of optimum high-subject-contrast image resolution. The advantages of the proposed blur definition and measurement technique of high-subject-contrast image resolution include: test object simplicity, ease of performing and interpreting the measurement, usefulness for all types of real-time scanners, and the need for only one scan for both axial and lateral resolution information at all image depths.