Are morphology and composition of gallstones related? An x-ray diffraction study

An x-ray diffractometric technique was used to study the crystalline composition of gallstones removed during surgery from 106 patients. Monohydrate cholesterol was found in the stones of 70 (66%) patients, either alone (33%) or in association with calcium salts (33%). The anhydrous form of cholesterol was found in the stones of 28 (26%) patients, either alone (10%) or in association with calcium salts (16%). These salts (vaterite, aragonite, and calcite) were found in 50% of cases in varying amounts (from 12% to 15% of the stone weight). Eight stones contained no cholesterol: 4 showed an amorphous pattern and 4 were composed of calcium carbonate salts. In 7 of 8 patients with bile duct stones concomitant with gallbladder stones, results of the diffractograms of the stones from the two different sites were comparable, even in 4 cases in which the stones were macroscopically different. Neither the macroscopic appearance nor the chemical structure of the stones appeared to be influenced by the patient's sex.