During mid-gestation, visualization of which structure indicates the biliary tree is present?

• A. Gallbladder
• B. Appendix
• C. Spleen
• D. Pancreas

Answer: (A)

Visualizing the gallbladder signals the biliary tree is present. The biliary system drains bile from the liver into the gallbladder and onward to the duodenum, so seeing a gallbladder in mid-gestation confirms that part of the biliary tract has formed and is patent. On ultrasound, the gallbladder appears as a small, fluid-filled sac with a thin echogenic wall, which is a normal early indicator of the biliary pathway.

The other structures aren’t direct markers of the biliary system. The appendix isn’t typically visualized in fetal imaging and isn’t part of the biliary tree. The spleen is a separate organ, and while the pancreas lies near the biliary tract, its visualization doesn’t indicate that the biliary tree itself is present.