Biliary

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Note

Across all major radiology and sonography references, there is uniform agreement regarding how gallbladder wall thickness is defined on ultrasound. The echogenic outer wall is included in the wall measurement. This convention is consistent regardless of the patient’s condition, the degree of distention, or the presence of pathology.

Multiple authoritative sources—spanning more than four decades of literature—describe the gallbladder wall in the same layered pattern:

1. Inner echogenic mucosal interface
2. Hypoechoic muscular/subserosal layer
3. Outer echogenic serosal layer

All three layers together constitute the measurable gallbladder wall.

This has been consistently demonstrated in radiology texts (Bluth & Benson, 2008; Bates, 2011; Hagen-Ansert, 2018; Siegel, 2011), classical foundational ultrasound papers (Finberg & Birnholz, 1979; Shlaer et al., 1981), more contemporary imaging studies (Gupta et al., 2021; Joo et al., 2012; Matcuk et al., 2014; Uggowitzer et al., 1997; Yokoe et al., 2013; Yarmenitis, 2001), hepatobiliary consensus and review articles (Gandolfi et al., 2003; Gomes et al., 2017), Radiology Assistant and Radiopaedia resources (Botz et al., n.d.; van Breda Vriesman et al., 2007; van Breda Vriesman et al., 2006), and additional supporting literature addressing gallbladder wall interpretation across modalities (Hwang, 2020; Parmar et al., 2017; Runner et al., 2014; Wheeler et al., 2018). All of these sources advocate including the outer echogenic line in the measurement—asserting that typically this is the only layer seen in a normal gallbladder.

The gallbladder wall thickness on ultrasound is measured from the inner echogenic mucosal interface (if seen) to the outer echogenic serosal/peritoneal interface. The outer echogenic line is part of the wall and is always included.