Gallbladder is distended and filled with heterogeneous solid material which is roughly isoechoic to the liver parenchyma. There is no internal flow on Doppler examination, and the gallbladder wall is unremarkable in thickness, and is not hypervascular. Common bile duct is not dilated, measuring 5 mm in diameter at the porta hepatis.
Conclusion
The most likely explanation for the appearance of the gallbladder is sludge, probably related to TPN administration.