The Mercedes Benz Sign: An Indicator of Gallstones
There are two types of gallstones: Pigment stones which are predominantly calcified and appear hyperdense on CT and cholesterol stones which are not visible on CT because they are embedded in bile overloaded with cholesterol. Less than half of these stones contain gas which can diffuse outside the stones in case of a cracking of the latter. This gas will then be the only indicator of the gallstones. This was the case of this 47 year old patient, with a history of a breast cancer who was referred to or department for a thoraco abdomino pelvic CT as part of her usual follow up. A presence air in a star shaped pattern was noted in his gallbladder, corresponding to the Mercedes Benz sign (Figure 1) The ultrasound supplement performed confirmed that it was indeed stones in the gallbladder (Figure 2)