Dissolution of calcified gallstones. Part I. Correlation of in vitro dissolution kinetics in methyl tert-butyl ether with patterns of calcification by computed tomography.

RATIONALE AND OBJECTIVES

The authors evaluated the relationship between stone computed tomography (CT) attenuation patterns and the kinetics of dissolution with methyl tertbutyl ether (MTBE).

METHODS

Single moderately and heavily calcified gallstones from 40 patients were selected from a gallstone library and classified for pattern of calcification by in vitro CT scan (dense, rim, core, and laminated). Each stone was placed in a 10-mL aliquot of MTBE for 24 hours. Stone residue was blotted dry and weighted at 8, 16, and 24 hours. Results were normalized with respect to stone size.

RESULTS

Only 1 of 40 (4%) specimens dissolved to particulate matter that was smaller than 2 mm. All (6 of 6) stones that were densely calcified showed virtually no dissolution. The rate of gallstone dissolution varied temporally within the rim, core, and laminated stone categories and was related to the composition of the layer exposed to the solvent at any given time.

CONCLUSION

The success and rate of dissolution may be predicted by the pattern of calcification as determined by computed tomography (CT).