Abdominal duplex examinations require high resolution ultrasound instruments and low-frequency pulsed Doppler transducers in the range of 2 MHz to 5 MHz. Sector, curved and phased array transducers are all satisfactory for visceral vascular examinations. A curved array transducer, optimized for the appropriate imaging depth and Doppler carrier frequency, facilitates imaging through inter and sub-costal windows. Phased array transducers provide excellent tissue characterization in patients with normal body habitus. The addition of color flow imaging facilitates identification of vessels, confirmation of aberrant vascular anatomy and recognition of disordered flow patterns. Power Doppler imaging excels in delineation of off-axis and low velocity blood flow and for defining the interface between the lumen and the vessel wall. Real-time compound and or harmonic imaging should be routinely used to improve image resolution and to decrease artifacts.
