Analysis of cases of nonvisualized gallbladder by ultrasonography.

To define the significance of nonvisualization of the gallbladder by ultrasonography, we studied follow-up data on 31 cases in which the gallbladder could not be identified despite adequate fasting. Thirty one cases of gallbladder disease included 15 cases of chronic cholecystitis due to cholelithiasis (13 cases) and choledocholithiasis (2 cases), 4 cases of cholelithiasis which were not surgerized, and 3 cases of cancer. There were 4 cases of diagnostic error in which gallbladder nonvisualization occurred despite a demonstrable lumen. The etiology of disease was not determined in the 5 remaining cases. Therefore 22 of 26 cases were found to have diseased gallbladders. The resasons for nonvisualization of the gallbladder by ultrasonography in the 19 cases which underwent surgicl exploration were: 17 cases due to chronic cholecystitis with cholelithiasis (13 cases), choledocholithiasis (2 cases) and cancer (2 cases), obliteration of the lumen due to cancer of the gallbladder in one cases, and technical error due to an unusual location of the gallbladder in one case. The mechanisms of diagnostic error in 4 cases seemed technical error due to an unusual location of the gallbladder in 3 cases and the obscured gallbladder by intestinal gas in one case. In conclusion, we feel that careful examination should be done to detect a gallbladder located unusually or obscured by intestinal gas in order to decrease the rate of diagnostic error when the gallbladder is not visualized by ultrasonography. Also, we recommend an oral cholecystography or ERCP for ultrasonic nonvisualized gallbladder.