Duplex ultrasound is a medical imaging technique that uses sound waves to create images of the structures within the body. It combines two types of ultrasound, namely, Doppler ultrasound and conventional B-mode ultrasound, to evaluate blood flow and structure of organs and tissues. Doppler ultrasound measures the speed and direction of blood flow in vessels, whereas B-mode ultrasound produces a two-dimensional image of the tissue being examined. Duplex ultrasound is a non-invasive and safe imaging technique that does not involve exposure to ionizing radiation, making it a preferred choice for many diagnostic applications.