Ultrasound Imaging Basic Principle: sound wave pulse emitted at >20 kHZ, some reflected, and some transmitted. Reflection from single signal – A-scan Reproduced from

B-Mode Imaging Energy displayed as:- amplitude, as in A-mode, - brightness, as in B-mode, - motion curve, as in M-mode. 2D image formed with linear or angular sweep. Reproduced from

B-Mode 2D Imaging Image built line by line: i) emitting the pulse, ii) waiting for reflected echoes iii) tilt beam & emit next pulse. Cardiac application: 2D visualization of beating heart. Reproduced from

Doppler Imaging Idea: moving source of sound undergoes Doppler shift. 1.Moving train 2.Blood flow: exploit frequency shift to estimate motion. Reproduced from & Wikimedia Commons.