Mercedes-Benz sign of gallstones

Case contributed by Dr Levente István Lánczi


CT requested upon urinary bladder tumor.

Patient Data

Age: 69 years
Gender: Female

An accidental finding of multiple, air-containing gallstones.

In the center of the gallstones the density is between -150 HU and -100 HU.

Case Discussion

Ultrasound is still the first line imaging tool for diagnosing gallstones. 

Gas or fluid containing gallstones are relatively rare findings on abdominal CT. Characteristic finding is the low density, star shaped center within a gallstone, producing a triradiate pattern, similar to Mercedes-Benz automobile sign.

CT can reveal air inside the stones: 

  • stones with central density under -100 HU are considered as gas containing gallstones
  • stones with central density between 0 and -100 HU can contain mixed gas and fluid

As a pathological background, degenerating stones can collect nitrogen gas in central fissures

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Case information

rID: 46896
Case created: 22nd Jul 2016
Last edited: 30th Jul 2016
Inclusion in quiz mode: Excluded

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