• Cholesterol stones (∼ 80% of cases)
  • Radiolucent with radiopaque areas due to calcifications (< 20%)
  • Composed of cholesterol and calcium carbonate
• Pigment gallstones
  • Black pigment gallstones
    • Radiopaque
    • Associated with hemolytic diseases such as sickle cell anemia, hereditary spherocytosis
    • Composed of calcium bilirubinate
  • Brown pigment gallstones
    • Radiolucent
    • Associated with infection