Chronic cholecystitis. An analysis of diagnostic strategies.

To define the optimal diagnostic approach for suspected chronic cholecystitis comprehensive management strategies were developed. Using a computer model, the frequency of appropriate surgery, inappropriate surgery, complications, death, and medical costs were compared in populations of patients with various disease prevalences. The optimal strategy began with ultrasonography, followed by an oral cholecystogram when the ultrasonogram was inconclusive. Oral cholecystogram also was employed when additional diagnostic studies failed to provide another explanation for the patient's symptoms. Compared with strategies using only ultrasonography or oral cholecystography, the combination strategy lowered the frequency of inappropriate surgery from 7.1 to 4.4% and direct medical costs from $1,877 to $1,766 per patient in a population with a 20% prevalence of chronic cholecystitis. The differences persisted at higher prevalences of cholecystitis and when sensitivities and specificities of the tests were varied over ranges reported in the literature. Diagnostic accuracy and direct medical costs could be improved by a more frequent interpretation of subtle abnormal ultrasonographic findings as inconclusive and by a more liberal use of oral cholecystography. This analysis demonstrates that a strategy combining ultrasonography and oral cholecystography is superior to the use of either test alone and is cost-efficient.