Common bile duct stones in non-dilated bile ducts? An ultrasound study.

In a consecutive series of 870 patients having cholecystectomy performed by the laparoscopic technique in a single surgical unit, prospective data collection has permitted analysis of the relationship between common bile duct (CBD) diameter, as measured pre-operatively by ultrasound (US) examination, and the frequency of CBD stones. Overall, 85 patients (9.8%) have been shown to have CBD stones; the interval frequency for CBD size 0-4, 4.1-6, 6.1-8, 8.1-10 and > 10 mm, was 3.9, 9.4, 28, 32 and 50%, respectively. Because most patients have small ducts (736 with CBD size < 6.1 mm) almost half (42) of those with CBD stones came from this group. In reporting CBD size as "not dilated', radiologists should remind clinicians that this does not equate with "no CBD stones'.