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The WES Sign

9/26/13

Who: Drs. Stokes and White

What: Wall Echo Shadow (WES) triad, also known as the double-arc-shadow sign 

How: Start by placing the curvilinear probe in the subcostal region and slowly move your probe towards the right upper quadrant. Being a fluid filled structure, a healthy gallbladder is visualized as an ovoid structure within the homogenous liver parenchyma, with an anechoic lumen. However, when the gallbladder lumen is filled with either multiple stones or one large stone, ultrasound waves are unable to penetrate readily. 

The WES triad when present consists of a well defined near wall, echos from stones immediately beneath the wall, and posterior shadowing caused by strong echos from stones in the gallbladder fossa. 

Image 1

WES still

Clinical Importance: WES is a sign of a contracted GB filled with stones.  While not a specific sign, the WES triad has been correlated with underlying cholecystitis. 

Youtube video: http://youtu.be/-rtnWOspoxw

Literature Support: Miller et al. J Emerg Med 30(1):69–74, 2006

Karim Ali, MD
Emory University SOM