What percentage of gall stones are radio opaque?

Ans is 'a' i.e., 10-20 Cholelithiasis:* Cholelithiasis is a common cause of epigastric or right upper quadrant pain in middle aged obese female patients.* Gall stones are composed of crystals of cholesterol monohydrate and variable amounts of calcium carbonate/ phosphate/ bilirubinate.* Only 15 - 20% of the gall stones are radio-opaque.* Gallstones are the most common biliary pathology.* It is estimated that gallstones are present in 10-15% of the adult population in the USA.* They are asymptomatic in the majority (> 80%).* Approximately 1-2% of asymp- tomatic patients will develop symptoms requiring cholecystectomy per year, making cholecystectomy one of the most common operations performed by general surgeons.