Tensile gallbladder fundus sign
The tensile gallbladder fundus sign is positive when the gallbladder fundus is seen to bulge into, and distort, the anterior abdominal wall and is a feature of acute cholecystitis.
It is particularly useful as an early sign of the condition on CT as it has around a 75% sensitivity and 95% specificity for acute cholecystitis in the absence of any other CT features.