What is the role of ultrasonography in the diagnosis of varicose veins and spider veins (telangiectasia)?

Updated: Sep 25, 2020
  • Author: Robert Weiss, MD; Chief Editor: William D James, MD  more...
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Duplex ultrasonography is the standard imaging modality for diagnosis of varicose insufficiency syndromes and for treatment planning and preoperative mapping.

Two-dimensional ultrasonography forms an anatomic picture based on the time delay of ultrasonic pulses reflected from deep structures. Structures that absorb, transmit, or scatter ultrasonic waves appear as dark areas; structures that reflect the waves back to the transducer appear as white areas in the image. Vessel walls reflect ultrasound; blood flowing in a vessel absorbs and scatters ultrasound in all directions. The normal vessel appears as a dark-filled white-walled structure.

Duplex ultrasonography is a combination of anatomic imaging by 2-dimensional ultrasound and flow detection by Doppler-shift. With duplex ultrasonography, after the 2-dimensional anatomic image is displayed, a particular spot in the image can be selected for Doppler-shift measurement of flow direction and velocity.

Color-flow imaging (sometimes called triplex ultrasonography) is a special type of 2-dimensional ultrasonography that uses Doppler flow information to colorize areas of the image in which flow has been detected. Vessels in which blood is flowing are colored red for flow in one direction and blue for flow in the other, with a graduated color scale to reflect the speed of the flow. Modern color-flow duplex ultrasonography equipment can provide flow information in conjunction with surprisingly high-resolution views of both deep and superficial venous systems. Structural details that can be observed include the most delicate venous valves, small perforating veins, reticular veins as small as 1 mm in diameter, and (using special 13-MHz probes) even tiny lymphatic channels.

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