In order to assess the association between common bile duct diameter and anthropometric measurements, both of which were continuous variables, correlation was used.
3 Regional Medical Advisor (East), GLRA-India.
Ultrasonography is an accurate, safe, non-invasive and inexpensive imaging modality, which is highly sensitive and specific for the detection of many biliary tree diseases . Ultrasonography is comparable in accuracy to oral cholecystography, radionuclide studies, computed tomography and magnetic resonance imaging, and more cost-effective .
Socio-demographic details related to age, sex and place of residence were recorded for each subject. The ultrasonographic findings with regard to common bile duct diameter were obtained. In order to reduce observer bias, the same expert radiologist was involved in conducting ultrasonography for all subjects. A 3.5 megahertz (MHz) transducer was used. The common bile duct was identified through its association with the portal vein in the long axis of the gallbladder. At this location the common bile duct and hepatic artery appear as two smaller circles anterior to the portal vein, giving an appearance of a face with two ears – also called a ‘Mickey Mouse’ sign. With the indicator directed toward the patient’s right, the right ear is the common bile duct and the left ear, the hepatic artery.
However, some authors like Reinus et al.,  have reported no relation of common bile duct diameter with age.
The mean weight and height of the participants was 51.4 kg (SD 12.25 kg) and 163.4 cm (SD 9.98 cm) respectively. The mean circumference measured at levels of chest, transpyloric plane, umbilicus and hip were 83.5 cm (SD 9.04 cm), 75.2 cm (SD 9.94 cm), 78.1 cm (SD 12.02 cm) and 87.2 cm (SD 10.0 cm) respectively.
The mean common bile duct diameters of proximal and distal parts were 4.0 mm (SD 1.02 mm) and 4.2 mm (SD 1.01 mm), respectively. A strong correlation was found between proximal and distal part of CBD due to constant diameter. Similar correlation has been reported by Adibi and Givechian  and Niederau et al., .
In order to compare the diameter across the five age groups, and test the null hypothesis that the groups have the same common bile duct diameters, we applied the Analysis of Variance (ANOVA). The difference was found to be statistically significant (p = 0.05).
Choledochojejunostomy, in which the donor CBD is anastomosed directly to the recipient jejunum, is usually performed in patients with pre-existing biliary disease such as primary sclerosing cholangitis, prior history of biliary surgery, or when a size mismatch exists between donor and recipient ducts. Post-transplant bile duct leaks may be due to ischemia, relative downstream obstruction, sphincter of Oddi hypertension, or from T-tube removal, and most commonly occur at the biliary-enteric anastomosis or T-tube exit site. Leaks may manifest as extravasation of contrast material from the T-tube site into the peritoneal cavity on direct cholangiography, or as single or multiple bilomas. 41
CT is useful for evaluation of biliary ductal dilatation and the measurements used in CT are applicable, but it is only moderately sensitive for detection of choledocholithiasis (with reported sensitivities between 25-90%). Only 20% of stones are high attenuation and up to 24% are isoattenuating to the surrounding bile (Figure 1). 7,8 Narrow window settings and coronal reconstructions may help accentuate the stone from adjacent bile or soft tissue. 9
Initial evaluation of suspected transplant biliary complication should include laboratory evaluation and transabdominal grayscale and Doppler ultrasound. When no T-tube is present, MRI/MRCP, with or without hepatocyte specific gadolinium agents, is the preferred imaging tool for further evaluation of the biliary tree and avoids the potential complications associated with ERCP. ERCP has a high failure rate in patients with Roux-en-Y reconstruction, except when double balloon enteroscopy is available to assess the biliary tree. Percutaneous transhepatic cholangiography is usually reserved for cases in which ERCP cannot be performed.
=Biliary tract emergencies have the potential to result in significant patient morbidity but frequently present with nonspecific and overlapping clinical features, thus presenting unique challenges in diagnosis and management. Imaging in this setting often requires a multimodality approach, particularly in complex or postoperative patients. Ultrasound remains the first-line imaging tool for investigation of suspected biliary obstruction, while MRCP with hepatobiliary contrast agents has emerged as a valuable tool in the evaluation of biliary tract injury. Advances in MRI and MRCP have likewise reduced the requirement for diagnostic ERCP. Appropriate selection and interpretation of imaging studies in acute biliary tract disease can aid in timely and accurate diagnosis and guide management of these conditions.
MRI/MRCP is less frequently indicated in evaluation of hemobilia due to lengthier examination times and suboptimal evaluation of the peripheral vasculature, but can effectively demonstrate blood products within the biliary system. Hemorrhagic bile appears as increased signal on T1-weighted MRI and decreased signal on T2-weighted MR. Blood products within the biliary system usually appear as filling defects on MRCP. Once the site of bleeding is identified, the site can be embolized in the interventional fluoroscopy suite using either microcoils or liquid embolic agents (Figure 6). 34 Surgical intervention is often unnecessary, as success of endovascular management at experienced centers approaches 100%. 36 Depending on the patient’s situation, percutaneous biliary drainage may also be necessary for successful drainage of biliary obstruction from intraluminal blood products.
Despite the dual therapeutic and diagnostic capabilities of ERCP, the invasive nature and inability to help detect extrabiliary abnormalities limit its diagnostic application as a first-line modality for bile leak detection. 24
Bile leaks typically manifest within one week of surgery, but may not become apparent for up to one month. CT and US may demonstrate free or loculated fluid but cannot reliably distinguish between bile leaks and other postoperative collections. As in the post-traumatic setting, hepatobiliary scintigraphy can provide functional information and demonstrate the presence of free or contained bile leakage. Delayed MRI imaging with hepatobiliary contrast agents may indicate the site of bile leak and help distinguish between fluid collections of biliary and nonbiliary origin by demonstrating contrast accumulation and communication with the biliary tree. MRI/MRCP may also delineate other postoperative complications, such as biliary strictures or retained stones.
Magnetic resonance cholangiopancreatography (MRCP) and abdominal MRI are highly accurate for imaging the biliary tree and is useful in multiple obstruction settings. For instance, it is useful for patients with obstructive jaundice in whom CT and ultrasound findings are inconclusive; when underlying mass or biliary tract neoplasm is suspected; or for evaluation of suspected ascending cholangitis and associated complications (Figure 2). 3 Since it is noninvasive, MRCP avoids the potential complications of endoscopic retrograde cholangiopancreatography (ERCP) and is especially useful in patients with surgically altered biliary anatomy not amenable to ERCP (eg, those with biliary-enteric anastomosis). 10,11 ERCP is now largely reserved for therapeutic purposes. 3,12
Biliary complications remain a major source of morbidity after liver transplant, with an incidence of 5-15%, and are usually observed within the early postoperative period (≤3 months after surgery). 27,37,38 Potential complications include anastomotic and non-anastomotic strictures, leaks, stones, ampullary dysfunction, biliary necrosis, and cholangitis.