Grayscale image contrast is primarily influenced by:

Grayscale image contrast is fundamentally influenced by compression settings. Compression in ultrasound refers to the adjustment of the range of amplitudes of the received echoes so that they can be displayed effectively on the screen. It enhances the differentiation between varying tissue types, thereby increasing the overall contrast in the image.

When compression is applied, weaker echoes from low-reflective tissues can be enhanced relative to stronger echoes, which helps to visualize structures that might otherwise be obscured. This adjustment allows a sonographer to optimize the appearance of soft tissue interfaces, enhancing the diagnostic utility of the ultrasound images.

While other factors like scan converter settings, transducer frequency, and echo amplitude play roles in image formation, they do not primarily govern the grayscale contrast the way compression settings do. The scan converter settings are more related to the digital processing of the images, transducer frequency can affect the resolution and penetration of the ultrasound waves, and echo amplitude is related to the strength of the signals received but not directly to contrast enhancement. Thus, compression settings are key in determining the contrast seen in grayscale images during an ultrasound examination.