Composition Analysis of Gallstones by Fourier Transformed Infrared Spectroscopy

Composition analysis of gallstones by Fourier transformed infrared spectroscopy (FTIR) was rarely reported in the past. There were 73 cases of gallbladder stones (GBS), 41 common bile duct stones (CBDS), and 42 intrahepatic stones (IHS) in this study. The percentages of stone composition, which included cholesterol, calcium carbonate, and calcium bilirubinate, were analyzed. In the GBS group, there were 33 cholesterol stones (45.2%), 28 pigment stones (38.4%), 7 calcium carbonate stones (9.6%), and 5 unclassified stones (6.8%). In the CBDS group, there were 5 cholesterol stones (12.2%), 34 pigment stones (82.9%), 1 calcium carbonate stone (2.4%), and 1 unclassified stone (2.4%). In the IHS group, there were 6 cholesterol stones (14.3%), 32 pigment stones (76.2%), and 4 calcium carbonate stones (9.5%). There were 17 cases which involved more than one site (e.g. GBS+CBDS, GBS+JHS, or CBDS+IHS, and 11 out of the 17 cases had stones of different composition. It was concluded that gallstones occur more commonly iii people over 50 years old. The female-to-male ratios of cholesterol, pigment, and calcium carbonate stones were 1.8, 1.3, and 1.0, respectively. Most of the BDS and IHS were pigment stones; whereas, in the GBS group, 33 out of 73 cases were cholesterol stones (45.2%). Gallstones were of a variety of colors and shapes, and to classify gallstones simply by their gross appearances would sometimes be misleading. It is worth mentioning that the existence of cholesterol stones in the biliary tree, intrahepatic or extrahepatic ducts, is not so uncommon.