 B-mode ultrasound scan

A B-mode ultrasound scan maps echo strength to displayed brightness and assembles multiple pulse-echo ultrasound lines into a spatial image. Each echo's location is inferred from beam direction and return time using an assumed sound speed. ^[ref]

A bright point represents a strong received echo, not a direct measurement of tissue density. Acoustic impedance contrasts, propagation losses and the instrument's display mapping all affect brightness. A moving image consists of repeated spatial frames; in an M-mode ultrasound scan, the second display axis instead tracks time along one beam.