The incidence of calculi in focal nonshadowing echogenicity in the gallbladder.
D000328:Adult; D000368:Aged; D002763:Cholecystectomy; D002769:Cholelithiasis / Q000175:diagnosis* / Q000453:epidemiology; D005188:False Negative Reactions; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D014463:Ultrasonography