Effect of display format on detectability.
The effects of black-echo (black dots on white background) and white-echo (white dots on black background) display formats on detectability of a wire embedded in an echogenic test object were compared. Trained observers were asked to note the presence or absence of the wire on a randomized series of 528 B scans (264 black-echo and 264 white-echo images), half of which contained a wire. The scans not containing a wire were used as controls. The specificity of the white-echo display (75 per cent) exceeded that of the black-echo display (54 per cent), with statistical significance at the 99 per cent confidence level. There was no measurable difference in sensitivity. These results are explained in terms of principles of visual physiology.
D014463:Ultrasonography