Also called B-mode echography, B-mode sonography, 2D-mode, and sonogram.
B-mode ultrasound (Brightness-mode) is the display of a 2D-map of B-mode data, currently the most common form of ultrasound imaging.
The development from A-mode to B-mode is that the ultrasound signal is used to produce various points whose brightness depends on the amplitude instead of the spiking vertical movements in the A-mode. Sweeping a narrow ultrasound beam through the area being examined while transmitting pulses and detecting echoes along closely spaced scan lines produces B-scan images. The vertical position of each bright dot is determined by the time delay from pulse transmission to return of the echo, and the horizontal position by the location of the receiving transducer element.
To generate a rapid series of individual 2D images that show motion, the ultrasound beam is swept repeatedly. The returning sound pulses in B-mode have different shades of darkness depending on their intensities. The varying shades of gray reflect variations in the texture of internal organs. This form of display (solid areas appear white and fluid areas appear black) is also called gray scale.

Different types of displayed B-mode images are:
The probe movement can be performed manual (compound and static B-scanner) or automatic (real-time scanner).
The image reconstruction can be parallel or sector type.

See also B-Scan, 4B-Mode, and Harmonic B-Mode Imaging.

A four dimensional B-mode ultrasound means length, width, and depth over time so that a moving three-dimensional image is seen on the monitor.

See 4D Ultrasound.

QB-mode (Quadratic Brightness-mode) images are gray scale images from the quadratic component. QB-mode achieves higher contrast and increased dynamic range than the standard B-mode ultrasound images, without loss in spatial resolution.

Compound B-mode imaging takes different forms and refers to different methods of creating the ultrasound image.
Real-time compound ultrasound improves the image quality of B-mode scanning by combining ultrasound information obtained from multiple angles. The used averaging process of compound B-mode reduces artifacts and improves the representation of true image data.
B-mode images and Doppler mode images (see also Duplex) can be compounded on the display to improve the visualization of the anatomical relationships between vessels and the surrounding tissues.

Harmonic B-mode imaging takes advantage of the non-linear oscillation of microbubbles. During harmonic imaging, the sound signal is transmitted at a frequency of around 1.5 to 2.0 MHz and received at twice this frequency. The microbubbles also reflect waves with wavelengths different from the transmitted one, the detectors can be set to receive only the latter ones and create only images of the contrast agent.
Using bandpass filters the transmitted frequency is separated from the received signal to get improved visualization of vessels containing ultrasound contrast agents (USCAs). The signal to noise ratio during the presence of microbubbles in tissue is four- to fivefold higher at the harmonic compared with the basic frequency.
Using harmonic B-mode imaging, harmonic frequencies produced by the ultrasound propagation through tissue have to be taken into account. The tissue reflection produces only a small amount harmonic energy compared to USCAs, but has to be removed by background subtraction for quantitative evaluation of myocardial perfusion.

See also Non-linear Propagation.