Gallbladder: follow the main lobar fissure

Answer a. The main lobar fissure is a bright line in the liver connecting the portal vein to the gallbladder neck. Follow it and it ends at the gallbladder. The falciform ligament and ligamentum venosum lie on the left side of the liver. The hepatic veins run towards the IVC, away from the gallbladder.

Answer d. A wall over 3 mm counts as thickened. Measure the anterior wall, nearest the probe, because the posterior wall blends with bowel and liver behind it. A thick wall has several causes, including cholecystitis, a recent meal, ascites and heart failure.

Answer b. Polyps attach to the wall, so they stay in place and cast no shadow. Gallstones move with the patient and cast a shadow. Sludge layers in the dependent part and moves slowly. Air in the wall gives bright lines with a dirty shadow and suggests emphysematous cholecystitis.

Answer a. The gallbladder contracts after eating and its wall looks thick. Judge cholecystitis on the combination of stones, sonographic Murphy's sign, wall thickening and pericholecystic fluid, alongside the clinical picture. A thick wall alone after a meal confirms nothing. Heart failure is one cause of wall thickening, not the only one.

Answer b. Rolling the patient left brings the gallbladder away from the ribs and moves bowel out of the way. The intercostal window is another option. A linear probe does not reach the gallbladder in most adults. More depth does not move gas out of the beam.