Gallstones

Gallstones, also called cholelithiasis, are concretions that may occur anywhere within the biliary system, most commonly within the gallbladder

Gallstones (cholelithiasis) describes stone formation at any point along the biliary tree. Specific names can be given to gallstones depending on their location:

  • cholecystolithiasis: gallstones within the gallbladder
    • the terms cholelithiasis or gallstones have been largely used in clinical practice by their own to refer to stones in the gallbladder 
  • choledocholithiasis: gallstones within the bile ducts

Biliary microlithiasis refers to gallstones <3 mm in diameter. 

Gallstones occur in ~10% of the population with a predominance in women (F:M = 2:1). The prevalence increases with age in both sexes 3

Genetics may have an important role in gallstone formation. Several studies have shown an association between age-adjusted prevalence of gallstone, ethnicity 4 and family history of gallstones:

  • highest age-adjusted prevalence (~50%): Pima Indians, some North and South American Indians
  • intermediate age-adjusted prevalence (up to 20%): Caucasians (20%), and Asian population (5-20%)
  • lowest age-adjusted prevalence (≤5%): Africans

Common risk factors for cholesterol gallstones include female sex, middle age, obesity, and positive family history (see 5-F rule) as well as recent rapid weight loss.

Gallstones may be symptomatic in only 25% of cases. The most common presentation is with biliary colic (right upper quadrant or epigastric abdominal pain or discomfort, especially after a fat-rich meal). Other symptoms include belching, bloating, flatulence, heartburn, and nausea.

Abdominal pain is often referred to the right shoulder. Patients may demonstrate this radiation to the tip of scapula by placing their hand behind the back and thumb pointing upwards: the "Collins' sign". This may be useful in distinguishing gallstone pain from esophagitis, gastritis, or duodenal ulcer in ~50% of patients 5

There are three types of gallstones 3,4,7-10:

  • cholesterol (10%)
    • >50% cholesterol contents; form with supersaturation of bile, nucleation and stone growth
    • predisposing factors
      • diet, sedentary lifestyle, rapid loss of weight, obesity, oral contraceptive pill, total parenteral nutrition (TPN)
      • ethnicity, genetic predisposition, older age, female sex
  • mixed (80%)
    • 20-50% cholesterol content
    • predisposing factor: similar to cholesterol stones
  • pigment stones (10%)
    • <20% cholesterol content; high bilirubin content and occur when there is supersaturation of unconjugated bilirubin
    • two further subtypes each with their own predisposing factors:

Some radiopaque gallstones may be seen on plain film:

Ultrasound is considered the gold standard for detecting gallstones 6:

  • greyscale ultrasound
    • highly reflective echogenic focus within gallbladder lumen, normally with prominent posterior acoustic shadowing regardless of pathological type (acoustic shadowing is independent of the composition and calcium content) 11
    • gravity-dependent movement is often seen with a change of patient position (the rolling stone sign)
  • color Doppler
    • may demonstrate a twinkling artifact and is particularly useful for identification of small stones

Pure cholesterol stones are hypoattenuating to bile and calcified gallstones are hyperattenuating to bile. Some gallstones are isodense to bile and these may not be clearly identified on CT.

  • T2: signal void or low signal outlined by markedly hyperintense bile within the gallbladder 
  • MRCP: focus of signal void inside the gallbladder

Possible imaging differential considerations in selected situations include

  • gallstone acoustic shadowing is prominent with
    • larger size stones (usually >3 mm for shadowing)
    • higher transducer frequency
    • focal zone at the level of gallstone
  • a gallbladder full of stones may paradoxically be hard to visualize (wall-echo-shadow sign)
Gallbladder and biliary tract pathology
Ultrasound - general index
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Article information

rID: 20125
Synonyms or Alternate Spellings:
  • Gallbladder microlithiasis
  • Cholecystolithiasis
  • Biliary microlithiasis
  • Gallstone
  • Gallbladder calculosis
  • Cholelithiasis
  • Biliary calculi
  • Biliary calculus

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Cases and figures

  • Figure 1: gallstones
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  • Gallstones and sp...
    Case 1: on ultrasound
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  •  Case 2: on ultrasound
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  • Case 3: on ultrasound
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  • Case 4: on CT
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  •  Case 5: on a radiograph
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  • AP
     Case 6: on a radiograph
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  • Case 7: on CT
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  • Case 8: on CT
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  • Case 9: on CT
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  • Case 10: on CT
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  • MRCP
    Case 11: on MRCP
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  • Case 13 : on MRI
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  • coronal
    Case 14: on MRI
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  • axial
    Case 15: on MRI
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  • Case 16: on CT
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  • Case 17
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  • Case 18
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  • Case 19: with hepatolithiasis
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  • Case 20
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  • Differential hepa...
    Case 21: with portal vein thrombosis
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  • Case 22: with choledocholithiasis
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