Abdominal X-ray
Radiologically, important evidence of gallstone disease can be found in:
- emphysematous cholecystitis
- gallstone ileus
- porcelain gallbladder (Kasper 2015)
The vast majority of cholesterol stones and also bilirubin stones do not give a shadow on radiography (Herold 2022). Only about 20% of cholesterol stones are calcified and thus radiopaque. Of the black pigment stones, about 75% are calcified. Brown pigment stones are basically not calcified (Krombach 2015).
Abdominal sonography
Abdominal sonography is the fastest and most sensitive method for detecting gallstones (Herold 2022). It is practically the domain in the diagnosis of gallstones (Krombach 2015).
The detection of gallstones up to a diameter of 1.5 mm (Kasper 2015) is successful due to:
- Positional displacement when the patient is repositioned.
- visualization of the stones in 2 planes
- arched anechoic reflux with posterior sonic release (Krombach 2015) so-called stone or sonic shadow (Sigman 2023). Only small concretions may lack the sonic shadow (Krombach 2015).
The rate of false-negative and false-positive results in sonography is between approximately 2 - 4 % (Kasper 2015).
Detection of gallbladder sludge:
- low echogenic activity
- does not produce a sonic shadow
- Gallbladder sludge is preferentially found in the most dependent position of the gallbladder (Kasper 2015)
Evidence of a dilated choledochal duct:
- in patients with preserved gallbladder > 7 mm in diameter
- after cholecystectomy > 9 mm diameter
- with age, the diameter of the choledochal duct usually increases (Herold 2022)
Complications such as acute cholecystitis are indicated by:
- pericholecystic fluid
- thickening of the wall (> 0.4 cm)
- Size change of the gallbladder (Sigman 2023)
- three-layeredness of the gallbladder wall
Cave: Three-layeredness and thickening of the gallbladder wall is also found in portal hypertension and acute hepatitis (Herold 2022).
Failure to visualize the gallbladder when bile ducts are present:
This indicates:
- obstruction of the bile ducts
- acute or chronic cholecystitis
- Z. n. cholecystectomy (Kasper 2015).
Endosonography
Endosonography plays a role especially in patients with microlithiasis (Dietrich 2008). It is also used to evaluate choledocholithiasis with sensitivity and specificity similar to MRI. Since this is an invasive examination, MRI is preferred when available (Hjaltadottir 2020).
Abdominal CT.
On CT, density measurements can be used to distinguish between the two types of stones.
Cholesterol stones float in the gallbladder, whereas pigment stones sediment at the bottom of the gallbladder (Herold 2022).
However, CT is not as good as sonography for assessing lithiasis of the bile ducts (Sigman 2023) because the sensitivity of CT is poor in this regard.
Abdominal CT is predominantly used for the diagnosis of cholecystitis. Here, the sensitivity is 94% and the specificity is 59% (Hjaltadottir 2020).
MRC(P)
This examination is used in particular to visualize the biliary tree (Sigman 2023). MRC(P) is used especially in cases of clinical v. a. gallstones and negative sonography. In this case, a filling defect can be detected in the event of lithiasis. The sensitivity is 93% and the specificity 96% (Hjaltadottir 2020).
ERC(P).
If other imaging techniques do not show a clear picture, further clues may be found with this. Additionally, ERCP is used to treat choledocholithiasis (Sigman 2023).
PTC
Because of the high rate of complications, PTC is a so-called "reserve method" if ERC(P) is not possible (Herold 2022).