The width of the common bile duct in relation to age and stone disease. Kaude JV. The common bile duct (CBD) was measured in 600 ultrasound studies. In normal patients the mean width of the CBD increased from 2.8 mm in the age group 20 years or younger to 4.1 mm in patients 71 years of age or older. The mean width of the CBD for all age groups in normal cases was 3.4 (range 2 to 11 mm).  Various authors report different normal ranges for the diameter of the common bile duct. The consensus is that most people have a common bile duct diameter of around 5mm, +/- 1 mm. However, there are reports were people with no hepatobilliary disease have a normal common bile duct size up to 10 mm. Also, there is a correlation between common bile duct diameter and age. Am J Gastroenterol. 2000;95(4):897. Conventionally, the upper limit of normal for the common bile duct as measured by ultrasound is considered to be 6 mm. This review is a somewhat personalized account of how that number became the convention and cautions the reader to avoid being slavish in the use of this number. It is concluded that, based on the visualization of the entire extrahepatic duct echographically, the normal inner diameter of common bile duct can be up to 10 mm, and there is a mild change of duct size with age. On MDCT, the common hepatic duct and CBD are visible in almost 100% of patients with or without biliary obstruction [1] . A normal range for CBD has not been established on CT. In an autopsy study the outer diameters of the duct ranged from 4 to 12 mm, with an average of 7.39 ± 1.64 mm [2] . The upper limit of normal for the CBD has been reported as 4–10 mm on ultrasound [3] , [4] , [5] , [6] and [7] . However, others found dilatation of the CBD in patients after cholecystectomy [7] and [10] . In this study we aimed to find the size of the normal common bile duct on MDCT. We searched age related changes in the diameter of the common bile duct. They demonstrated minimal increase in the common bile duct diameter: 3.6 mm ± 0.26 at age 60 years and 4.0 mm ± 0.25 at age 85 years or older. Of course, Dr Laks correctly asserts that even though the expected value (mean) of the extrahepatic bile duct diameter may not vary with age, its reference range, that is its CI, may do so in such a manner as to include the 1.0 mm per decade value in its upper limit. In the published literature the upper limit of the CBD has been reported as 4–10 mm on ultrasound [3] , [4] , [5] , [6] and [7] . The mean diameter of the common bile duct measured by US was reported as 4.1 mm in the study by Parulekar [4] . However, others found dilatation of the CBD in patients after cholecystectomy [7] and [10] . In this study we aimed to find the size of the normal common bile duct on MDCT. We searched age related changes in the diameter of the common bile duct. In fact, 1,000 of their 1,018 patients, all aged at least 60 years, had duct diameters less than 6.0 mm, which directly refutes 1.0 mm per decade as an upper limit of normal. Of course, Dr Laks correctly asserts that even though the expected value (mean) of the extrahepatic bile duct diameter may not vary with age, its reference range, that is its CI, may do so in such a manner as to include the 1.0 mm per decade value in its upper limit. In 1979, a landmark study by Parulekar 1 established anupper limit of normal for the common bile duct of 7.0 mm ina population of 73 patients aged between 20 and 65 years. Inthe early 1980s, reports of increasing duct size with increasingage began to appear.  Abstract. Conventionally, the upper limit of normal for the common bile duct as measured by ultrasound is considered to be 6 mm. This review is a somewhat personalized account of how that number became the convention and cautions the reader to avoid being slavish in the use of this number
http://www.ncbi.nlm.nih.gov/pubmed/6873071 http://www.answers.com/Q/What_is_the_normal_size_of_the_common_bile_duct http://www.uptodate.com/contents/ultrasonography-of-the-hepatobiliary-tract/abstract/2-5 http://www.sciencedirect.com/science/article/pii/S0720048X10005528 http://pubs.rsna.org/doi/full/10.1148/radiol.2253020309 http://www.sciencedirect.com/science/article/pii/S0720048X10005528 http://pubs.rsna.org/doi/full/10.1148/radiol.2253020309 http://edus.ucsf.edu/sites/edus.ucsf.edu/files/wysiwyg/Bile%20Duct%20US%20Horrow%202010.pdf http://www.nature.com/ajg/journal/v95/n4/full/ajg2000239a.html
normal common bile duct above normal age