Answer #41

The correct answer is E: B mode Doppler. This is a good question to review the different ultrasound modalities and know which ones are scanned and non scanned.

A scanned modality means the ultrasound transducer scans across a 2 dimensional plane to collect data and create a 2 dimension image. Older transducers used to have mechanically moving parts to move a set of crystals in this fashion. Modern transducers use electrical scanning techniques and do not have moving parts.

PW and CW Doppler are non-scanned since they only interrogate velocities along a line that is chosen by the user. Information is given only as a set of velocities seen along that line (Y axis) across time (X axis).

M mode is similar in that it gives information only along a line of interrogation, however it given us distances (Y axis) across time (X axis)

A mode ultrasound is not really used clinically. It uses only one line of interrogation like M mode but plots ultrasound intensity (Y axis) across time (X axis)

B mode ultrasound is a scanned modality that gives us 2 D images as the ultrasound beam scans across a 2 D plane. It was the major breakthrough that allowed for more practical application of ultrasound for diagnostic purposes.