<prompt> Duplex ultrasound is a combination ofA mode and pulse wave dopplerB mode and pulse wave dopplerM mode and spectral doppler3D USG and Elastography  <response>: Duplex Scan Combination of B-mode imaging with Pulsed Doppler USG - gives both anatomical physiological information of vascular system. Colour Duplex Scan Addition of colour frequency mapping - Colour Duplex imaging. 