Pearls & Pitfalls for Vascular Ultrasound
1. Bedside ultrasound can provide you with valuable data to help you make critical diagnoses and expedite patient care. Minimize the chances of a false positive or false negative scan by approaching each scan with an open and critical mind. Don’t inadvertently “see” what you are hoping to find.
2. Always visualize and identify adjacent structures and anatomical landmarks. Figure out “where you are” in the body before you jump to any conclusions. Novice sonographers will place the ultrasound probe right over the point of interest, make a quick diagnosis, and put themselves at risk for common pitfalls. Improve your accuracy by obtaining multiple views of the target structure.
3. Most vascular ultrasounds are performed with a high frequency, linear array transducer. Pay close attention to the depth markers on the side of the image and ask yourself if the sonographic images you see make sense with anatomical expectations.
4. Lymph nodes will appear as round or oval shaped hypoechoic structures on bedside ultrasound. Enlarged lymph nodes can often be mistaken for a clotted vessel in the short axis view. Obtaining a long axis view can help delineate the borders of the structure you are evaluating. Lymph nodes will have a well-defined border when you rotate your probe.
5. Utilize power and color Doppler to provide you with physiologic and anatomic information that can help you make the proper diagnosis.
6. Always correlate your sonographic findings with the clinical picture. Evaluating lymph nodes via ultrasound is beyond our scope of clinical practice as emergency physicians. Ensure appropriate follow up and further evaluation if suspicious appearing lymphadenopathy is visualized on a bedside scan. Abnormal lymph nodes are usually rounder with peripheral or mixed vascularity.
Brady Pregerson manages a free online EM Ultrasound Image Library and is the author of the Tarascon Emergency Department Quick Reference Guide. For more info visit EMResource.org.
Teresa S. Wu is the Assoc. Residency Director and Director of Ultrasound and Simulation Based Training for the Maricopa EM Program in Phoenix.