cbd dilation size

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.

Dynamic hepatobiliary scintigraphy can detect the presence and severity of an active bile leak. Progressive intra-abdominal accumulation of radiotracer that does not conform to the morphologic appearance of the bowel is characteristic (Figure 4). 22 Its main limitation is poor spatial resolution, which can be partly overcome with use of SPECT/CT. 19.23

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.

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.

Biliary leaks after liver transplant

The American Society for Gastrointestinal Endoscopy has proposed a risk-stratified management algorithm to determine which patients with suspected choledocholithiasis would most benefit from further imaging based on clinical predictors at initial evaluation with transabdominal US. 5 The risk factors are divided into very strong, strong, and moderate (Table 1). Additional biliary imaging with MRCP or endoscopic ultrasound (EUS) may be most helpful in those at intermediate probability (10-50%) of choledocholithiasis – patients with only one “strong” predictor and/or at least one moderate predictor – to determine potential need for endoscopic stone extraction. Given the frequent need for therapeutic intervention in patients with high probability of choledocholithiasis – those with any “very strong” predictor or both “strong” predictors – preoperative ERCP or operative cholangiography is suggested instead.

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

MRCP with hepatobiliary contrast agents such as gadoxetate disodium (Eovist; Bayer Healthcare Pharmaceuticals, Berlin, Germany) can provide useful functional and anatomic information and in many cases may supersede both scintigraphy (through superior anatomic detail and spatial resolution) and ERCP (by demonstrating peripheral sites of leakage that do not opacify by retrograde injection) in the dynamic evaluation of biliary injury. Delayed hepatocyte phase T1-weighted MR imaging may allow improved characterization of biliary anatomy by providing a higher signal-to-noise ratio in the bile duct than can be achieved with conventional T2-weighted MR imaging. 25 Extravasation of contrast material in the liver, perihepatic space, peritoneum, or pleural cavity is indicative of bile leak. Pooling of contrast material within an intrahepatic or perihepatic fluid collection implies direct communication with the biliary tree. 26

Traumatic bile leaks

Biliary tract injury is a rare complication of abdominal trauma, with a reported prevalence of 2.8–7.4% in patients sustaining blunt hepatic injury. 17,18 Injuries to the extrahepatic bile ducts usually result from acute deceleration and tend to occur at sites of anatomic fixation, such as the intrapancreatic portion of the CBD. Injuries to the intrahepatic bile ducts may be seen in the setting of parenchymal liver injury.

Bile leaks have been associated with various surgical procedures, including open and laparoscopic cholecystectomy, hepatic resection, liver biopsy, liver transplantations, ERCP, percutaneous transhepatic cholangiography (PTC), and ablation of hepatic tumors. 27,28 Significant postoperative bile leaks have been reported in up to 1% of patients following laparoscopic cholecystectomy, 0.5% of patients after open cholecystectomy and in 2%–25% of patients after orthotopic liver transplantation or hepatic resection. 24,29,30 Postoperative bile leaks can go unrecognized due to nonspecific imaging findings and even less specific clinical features, which may be attributed to other more common postoperative complications. Intraperitoneal bile collections may also be difficult to distinguish from other postoperative fluid collections.

Cbd dilation size

Article in press: May 28, 2015

A study by Carriere et al[42] showed a EUS yield of 28.7% in a cohort of 94 patients with unexplained isolated CBD dilatation, although an undetermined number of subjects of the group underwent endoscopy because of abdominal pain and/or abnormal liver function tests, thus suggesting a higher pre-test probability of pathological findings.

Pathologic conditions are also able to induce isolated bile duct dilatations with non-specific symptoms or biochemical abnormalities. Choledocholithiasis, which develops in about 10%-20% of patients with gallbladder stones, may be asymptomatic in half of cases and CBD stones cannot always be identified by traditional non invasive imaging techniques[22]. Reported sensitivity in detection of CBD stones is 18%-74% for TUS and 50%-90% for CT[23-25]. Recently developed imaging modalities, such as MRCP and helical computed tomographic cholangiography (HCT-C) have shown higher sensitivity than TUS and conventional CT, and remain less invasive than ERCP[26]. However, EUS is considered more accurate in detecting CBD stones, especially if smaller than 5 mm in diameter, which are sometimes not identified by MRCP and HCT-C[26]. When choledocholithiasis is suspected, sensitivity of EUS reaches 90% for the detection of CBD stones[27-29]. In a prospective study, performed by Fernández-Esparrach et al[30] on patients with dilatated biliary tree, EUS increased the pretest probability of accurately diagnosing choledocholithiasis as the cause of obstruction from 49% to 84%. On the contrary, this probability decreased from 49% to 0% if EUS ruled out lithiasis as the cause of obstruction[30].

Examples of pathologic findings identified on endoscopic ultrasound in patients with negative prior imaging tests. A: Choledocholithiasis: Small stones in the common bile duct; B: Small pancreatic cancer; C: Small duodenal diverticulum with bile duct indentation (see arrow); D: Ampullary carcinoma with pancreas invasion; E: Inflammatory thickening of the distal common bile duct.

ACKNOWLEDGMENTS

Several studies in the last 20 years reported an increase in the CBD diameter in older patients, even if with consistent variability[6,7,9,10,12]. Based on autoptic observations, some authors identified loss of elastic fibers and proximal compensatory dilatation due to distal sclerosis as potential causes of the phenomenon[13]. Moreover, the fragmentation of the longitudinal smooth myocyte bands in elderly subjects and use of drugs such as calcium antagonists and nitroglycerine, may reduce contractility and cause hypotonus of the duct[12,14]. Finally, prior cholecystectomy seems to influence CBD diameter since gallbladder physiologically plays a role in accommodation of pressure fluctuation in biliary system which, after surgery, could be transferred to bile duct causing dilatation[11,15-17].

First decision: October 14, 2014

In 2001, a prospective study performed by Kim et al[41] showed the existence of pathological conditions in subjects with dilatated CBD, despite the lack of symptoms, jaundice or causative lesions in TUS. Among the 49 patients who underwent ERCP, a significant prevalence of abnormal findings likely causative of dilatation (periampullary duodenal diverticula, benign strictures, choledochal cysts, anomalous pancreaticobiliary ductal anatomy and distal CBD masses), associated with both normal or altered liver chemistry tests, was found.

IMPACT OF EUS IN THE DIAGNOSTIC WORK UP OF CBD DILATATION

Correspondence to: Claudio De Angelis, MD, Professor, Department of Gastroenterology and Digestive Endoscopy, “Città della Salute e della Scienza”, University of Turin, corso Bramante 88, 10126 Turin, Italy. [email protected]

In 2007, Malik et al[3] retrospectively evaluated a cohort of patients with CBD dilatation and non-diagnostic imaging (TUS, CT or MRCP), previously performed for abdominal pain, weight loss or elevated liver enzymes in serum. These patients underwent EUS, being divided into two groups based on the level of clinical suspicion for biliary pathology (32 patients with normal liver chemistry tests and 15 patients with elevated enzymes)[3]. In the first group, the authors identified two findings on EUS (6%) potentially causative of biliary dilatation, a 7-mm stone of the CBD and a periampullary diverticulum. In the second group, 8 significant findings (53%) were observed: 4 periampullary diverticula, 3 choledocholithiasis and 1 ampullary tumor, not previously detected by TUS and CT.