PREDICTION OF GALL STONE COMPOSITION BY ULTRASOUND - IMPLICATIONS FORNONSURGICAL THERAPY

Oral cholecystography is the basic radiodiagnostic procedure required to assess chemical composition of gallstones as well as functional sta tus of gall bladder prior to non-surgical management of gallstones. Ho wever, the value of ultrasound in non-surgical management of gallstone s is yet to be proved. In this study we attempt to establish sonograph ic criteria which will predict the composition of gallstones prior to their non-surgical treatment. For this purpose the ultrasonographic ch aracteristics of 233 patients with gallstone disease and functioning g all bladders were studied and an effort was made to correlate choleste rol and calcium content of different types of stones (as estimated by X-Ray powder diffraction study and atomic absorption spectrophotometry ) with their ultrasonographic characteristics. Sonographic criteria fo r the presence of cholesterol stones were those which were floating an d gallstones producing acoustic shadowing without internal echoes from within the stone. In detecting findings which would predict the prese nce of cholesterol stones on ultrasound, ultrasound had a sensitivity of 72.90% and a specificity of 100%. The predictive values of positive findings and negative findings were 100% and 93.4%, respectively. The demonstration of typical features of cholesterol stones on ultrasound obviates the need for oral cholecystography.