Gallstone analysis using Fourier transform infrared spectroscopy (FT-IR)

Background: Gallstone analysis is important in determining the possible etiology of stone formation and the pathophysiology of cholelithiasis. Physical analysis using Fourier transform infrared spectroscopy (FT-IR), compared to chemical analysis, requires minimal sample volume, shows uniform sensitivity and specificity for all components and provides quantitative results with greater reproducibility. We studied the characteristics and distribution of gallstones using FT-IR in addition to the risk factors for gallstone formation in Korean patients. A better understanding of the mechanism underlying stone formation may help prevent gallstone development. Methods: Physical analysis of gallstones in 490 patients who underwent cholecystectomy was carried out using the FT-IR system 2000 (Perkin-Elmer Co.) and Spectrum(TM) software (Perkin-Elmer Co.). Visual inspection of the size, color, consistency and surface of the stones was compared with the physical characteristics. Clinical, demographic and laboratory findings were evaluated and compared with the gallstone components. Results: The FT-IR evaluation showed that most gallstones were composed of a single component (84.1%); cholesterol was the most commonly observed element among the major components (50%, 245/490). Morphological classification according to color, consistency and surface was different from the FT-IR composition analysis. There were significant differences in the components based on age, obesity, education level and the presence of diabetes mellitus. Conclusions: The results of this study show that physical analysis of gallstones with FT-IR provides important information on stone composition, distribution and risk factors. These study results will help improve our understanding of the pathophysiology of gallstone disease in the Korean population, where there is a high frequency of hepatobiliary disorders.