In B-mode imaging, where is the amplitude represented on the image?

In B-mode imaging, also known as brightness mode imaging, the amplitude of the returned ultrasound signals is represented in the z-axis of the image. This mode constructs images based on the strength or amplitude of echoes returned from tissue interfaces.

The x-axis typically represents the lateral position or the horizontal extent of the scanned area, while the y-axis shows the depth of the structures being imaged. The z-axis, however, correlates to the intensity or brightness of the pixel, indicating the amplitude of the echoes – brighter areas represent stronger echoes from denser tissues, while darker areas indicate weaker echoes. This representation allows clinicians to visually assess different tissue characteristics and differentiate between normal and abnormal findings in the ultrasound image.

The time-axis is not relevant in this context, as it's more commonly used in Doppler ultrasound to represent the time-variant nature of the blood flow or motion being studied.

Thus, the correct representation of amplitude in B-mode imaging clearly defines how the information from echoes is translated into a visual format that clinicians can interpret during examinations.