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cbd size ultrasound

Cbd size ultrasound

A single measurement of the bile duct can be misleading as the duct may be normal at this point, yet be distended lower down in early obstructive jaundice. Thus, the common bile duct was measured at three locations- at the porta hepatis, in the most distal aspect of head of pancreas and mid-way between these points [ Table/Fig-1 ].

The size of the common bile duct is a predictor of biliary obstruction and it’s measurement is therefore an important component in the evaluation of the biliary system. Availability of normal measurements of the common bile duct would help to distinguish obstructive from non-obstructive causes of jaundice.


1 Demonstrator, Department of Anatomy, College of Medicine & Sagore Dutta Hospital, Kolkata, India.

Mean and standard deviation of common bile duct diameter by age group

Vivek Lal

Background: Ultrasonography is the diagnostic method of choice for visualization and rational work-up of abdominal organs. The dilatation of the common bile duct helps distinguish obstructive from non-obstructive causes of jaundice. Availability of normal measurements of the common bile duct is therefore important. There exists significant variations in the anthropometric features of various populations, regions and races.

We wanted to assess the width of the common bile duct (CBD) in an asymptomatic elderly (> 75 years) population, since no previous report has particularly considered the important age-related increase in CBD diameter for this patient group. CBD width of 92 asymptomatic people over 75 years of age (mean 84.7 years, range 75–96 years) without clinical or laboratory evidence for biliary, hepatocellular or pancreatic disease was measured by real-time high-resolution ultrasound of the upper abdomen. All examinations were performed by one experienced radiologist. Mean values were calculated for three groups: patients with and without cholecystolithiasis and after cholecystectomy. Statistical analysis was carried out by analysis of variance. Considering the measurements of all patients, the mean width (± SD) of the CBD was calculated as 6.5 ± 2.5 mm. The difference between patients without cholecystolithiasis (6.2 ± 2.3 mm) and patients after cholecystectomy (8.7 ± 2.9 mm) was statistically significant (P < 0.0001). Cholecystolithiasis (6.0 ± 1.6 mm) proves not to be an additional factor for CBD widening in comparison with patients without stone disease. The CBD of these very elderly subjects shows a considerable increase in comparison with the recommended borderline values in the ultrasound literature. An upper limit of 10 mm seems reasonable for patients with and without cholecystolithiasis. A significant increase in CBD width after cholecystectomy was found and measurements up to 14 mm may occur. Measurements have to be correlated with clinical and laboratory findings.