ULTRASONOGRAPHY

Noninvasive imaging of the biliary tree frequently begins with transabdominal ultrasound, which provides a global picture of the liver and is nearly universally available. There is no radiation exposure, and contrast agents are not required. Intrahepatic ductal dilatation can be visualized easily and the size of the bile duct can be documented. Ultrasound also provides imaging of the gallbladder and detects gallstones. For detection of choledocholithiasis, ultrasound has a high specificity, but the sensitivity does not exceed 68% and is often lower than 50%.^1,2 The sensitivity decreases if the stones are small and the bile ducts are not dilated. Ultrasound is highly accurate (78% to 98%) for detecting extrahepatic biliary obstruction.² When used in conjunction with the clinical evaluation, ultrasound allows differentiation between liver parenchymal disease and extrahepatic biliary obstruction with a reasonable sensitivity and high specificity.² Ultrasound is less accurate, however, at defining the level and cause of obstruction, with accuracy rates ranging from 27% to 95% and 23% to 88%, respectively.² In addition, ultrasound is limited in the ability to distinguish malignant from benign causes of obstruction.²

MAGNETIC RESONANCE CHOLANGIOPANCREATOGRAPHY AND MULTIDETECTOR COMPUTED TOMOGRAPHY CHOLANGIOGRAPHY

Magnetic resonance cholangiopancreatography (MRCP) is a magnetic resonance imaging (MRI) study (and thus noninvasive) that is dependent on the high T2-signal characteristics of bile. It does not require administration of oral or intravenous contrast material. For the detection of choledocholithiasis, MRCP has a sensitivity ranging from 81% to 100%, a specificity ranging from 96% to 100%, and high overall diagnostic accuracy (Fig. 70-1).³ In addition, MRCP is highly accurate in demonstrating the presence of benign and malignant strictures⁴ and allows a thorough evaluation of the intrahepatic bile ducts. In patients suspected of having post-liver transplant biliary complications, intravenous administration of mangafodipir trisodium (Teslascan, Amersham Health, Princeton, NJ) may be used. This agent is excreted primarily in the bile and may improve imaging sensitivity for post-liver transplant biliary leaks and strictures.⁵ An MRI can be performed as well with an intravenous contrast agent, such as gadodiamide (Omniscan, GE Healthcare, United Kingdom) or gadopentetate dimeglumine (Magnevist, Bayer Healthcare, Leverkusen, Germany or Multihance, Bracco, Princeton, NJ), to detect and characterize mass lesions in the liver, porta hepatis, or pancreas. Contraindications to MRI include a cardiac pacemaker, automatic implantable cardioverter defibrillator, and some types of cerebral aneurysm clips. A particular concern about gadolinium-based intravenous contrast agents is that they may precipitate nephrogenic systemic fibrosis, a rare scleroderma-like disease manifested by hardening of the skin and fibrotic changes that affect multiple organs. The cause remains unclear, but reports suggest that patients with preexisting kidney disease (renal failure) are at greatest risk.^6,7

Figure 70-1. Choledocholithiasis on magnetic resonance cholangiopancreatography (MRCP) and endoscopic retrograde cholangiopancreatography (ERCP). A, MRCP showing filling defect in distal bile duct (arrow). B, Corresponding ERCP with same filling defect.

Multidetector computed tomography cholangiography (MDCT) with multiplanar reformation is a computed tomography (CT)-based imaging study. MDCT is a combination of rapid volume acquisition and thin-slice imaging. Water is used as an oral contrast agent for the biliary tree, and intravenous iodinated contrast is also administered. Images acquired in the axial plane can be reconstructed sagittally or coronally and reformatted three dimensionally. The intravenous contrast dye is not excreted in bile but enhances adjacent surrounding visceral structures such as the liver, pancreas, and other soft tissues. Bile ducts thus appear as low attenuation structures that are best visualized if dilated. The sensitivity and specificity of MDCT for bile duct strictures have been reported to be 85.7% and 100%, respectively.⁸ MDCT also has a high sensitivity and specificity for the detection of bile duct stones.⁹

TECHNIQUE

Review of CT and MR imaging of the liver prior to percutaneous THC can help determine the best approach (i.e., from the right or left side) and the location of the dominant dilated ducts and help avoid traversing adjacent structures, such as the colon, unintentionally. Dilated bile ducts on the left side may be easily accessible with a minimal number of needle passes with use of ultrasound guidance from a subxiphoid approach.¹² A standard right-sided approach is used most frequently, however, and is performed from an intracostal approach, usually via the mid-axillary region below the 10th intercostal space. Higher punctures increase the risk of pneumothorax or biliary pleural effusion.

From either side, the procedure is initiated by advancing a 22-gauge needle under fluoroscopic guidance centrally toward the liver hilum and gently injecting contrast as the needle is withdrawn slowly. The initial use of such a small needle reduces hepatic trauma as well as the likelihood of bleeding despite the potential need for multiple needle passes to cannulate a bile duct, particularly when the bile ducts are not dilated. Ultrasound guidance and CT guidance can be used to access nondilated bile ducts.^13,14

When a bile duct is cannulated, a diagnostic cholangiogram can be performed. Isolated ducts, because of strictures or stones that do not communicate with the rest of the biliary tree, may need to be opacified via additional needle passes. If the procedure is only diagnostic, and biliary obstruction is not evident, the needle is simply withdrawn. If the biliary system is obstructed, however, serious consideration should be given to traversing the obstruction and leaving a decompressive “external-internal” tube in place; abandoning an obstructed biliary system may lead to bile leakage from the puncture site. The risk of hepatic arterial injury is reduced by using a peripheral intrahepatic bile duct for final access. If the duct cannulated initially is too central (the larger branches of the hepatic artery tend to be more central), a more peripheral duct should be chosen for access into the biliary tree. Frequently, use of a second needle to puncture a more peripheral duct is required, and the initial needle is used to opacify and visualize this new and safer access duct. A 0.018-inch “micro” wire is then advanced via the needle into the biliary tree and the access system “upsized” by the passage of catheters of increasing diameter over the wire. When access is gained, the obstruction can be traversed and an external-internal biliary tube can be placed (Fig. 70-2). These tubes provide drainage holes positioned above the level of obstruction; the distal pigtail is configured within the small intestine. The size of the tube usually ranges from 8 to 12 French. A larger tube may yield better decompression, but care must be taken not to place a tube in which the size may actually obstruct drainage of smaller ducts, particularly in the setting of primary sclerosing cholangitis (PSC), in which many of the obstructed ducts are not dilated. If the obstruction cannot be traversed during the initial attempt, a drainage catheter can be left proximal to the obstruction in the biliary tree (external drainage), and subsequent attempts can be made via this access after several days of drainage. This delay often allows inflammation to decrease and increases the likelihood of subsequent internalization of a catheter. Generally, the external-internal drainage tube is left to external drainage until fever or blood in the biliary tree resolves. Capping of the external end of the tube to permit internal drainage only decreases biliary fluid losses, which can be more than 1 liter per day, and prevents associated dehydration or electrolyte abnormalities. Bile samples obtained during the initial procedure can be sent for culture or cytology.

Figure 70-2. Schematic showing percutaneous transhepatic cholangiography. A, A peripheral bile duct is identified and entered with a needle. B, A guidewire is passed through the needle across the obstructing lesion into the duodenum. C, The needle has been withdrawn. D, An internal-external catheter is inserted over the guidewire.

Contraindications to percutaneous THC include coagulopathy. Generally the procedure is thought to be safe with an international normalized ratio (INR) of less than 1.8 and platelet count greater than 50,000/mm³. Any abnormalities should be corrected immediately before the procedure. Marked ascites between the liver and puncture site increases the risk of bile leakage, whereas a tortuous biliary catheter course may lead to malposition of the catheter or difficulty with future manipulations. In the presence of a substantial amount of perihepatic ascites, a pre-procedure paracentesis can be performed or ultrasound guidance can be used to place a small temporary peritoneal drainage catheter adjacent to the liver for the duration of the procedure. Biliary sepsis can be minimized by avoiding overdistention of the bile ducts and limiting the number of manipulations during the procedure. As soon as a tube is placed, it can be used as an access for further manipulations or interventions.

Following initial biliary decompression, further intervention should be avoided until fever and sepsis have resolved. Patients need to be monitored closely for the first 24 to 48 hours following the procedure. Brisk bleeding around the catheter site, through the catheter itself, or from the gastrointestinal tract suggests the possibility of hepatic arterial injury.¹⁵ Presentation of a hepatic artery pseudoaneurysm can be delayed, sometimes for a week or two after the initial procedure. If bleeding persists, the hemoglobin level drops substantially or the patient becomes hemodynamically unstable, hepatic angiography should be considered, and, if an injured arterial branch is demonstrated, embolization should be performed. A small amount of blood in the biliary tube or bile ducts following the original procedure, or during subsequent manipulations, is frequently self-limited and clears within one or two days.

POSTOPERATIVE BILIARY STRICTURES

Postoperative strictures may occur following laparoscopic cholecystectomy, major hepatic resection, and liver transplantation at a choledochocholedochal anastomosis or within an intrahepatic duct as a result of ischemia or recurrent PSC (Table 70-1) (see Chapters 66, 68, and 95). Dilation of a postoperative or other benign biliary stricture can be performed via percutaneous THC or through a mature, surgically-placed T-tube tract. Maturation of the T-tube tract usually requires six weeks. Percutaneous THC and biliary balloon dilation may be performed at the same session in the absence of clinical signs of cholangitis or sepsis. An 8-French or 10-French transhepatic tube is left in place, and the patient returns for repeat cholangiography six weeks later, at which time further stricture dilation is performed if bile duct narrowing of 30% or greater persists. The tube is then repeatedly upsized to a 12-French tube to facilitate healing of the stricture at a larger diameter. If the stricture resolves on follow-up, the biliary tube can be removed; otherwise, a similar procedure should be performed after six to eight weeks.

Table 70-1 Principal Causes of Benign Biliary Strictures

In one of the largest series published with long-term follow-up, percutaneous biliary balloon dilation was performed in 85 patients with a benign biliary stricture.¹⁶ In the 75 patients with follow-up, 205 percutaneous procedures were performed during 112 treatments of 84 biliary strictures. Stricture balloon dilation from 8 to 12 mm was performed. Procedures were repeated at 2- to 14-day intervals until cholangiography demonstrated free drainage of contrast material to the small intestine and no residual stenosis. An internal-external biliary drain was left in place for a mean of 14 to 22 days and removed if the patient did well when the catheter was clamped and had a normal cholangiogram. All procedures were technically successful. A total of 52, 11, 10, and 2 patients underwent a total of one, two, three, and four dilations, respectively. Major complications occurred in 2% of procedures: two subphrenic abscesses, one hepatic arterial pseudoaneurysm, and one case of hemobilia. The probability that clinically significant restenosis did not develop at 5, 10, 15, 20, and 25 years was 0.52, 0.49, 0.49, 0.41, and 0.41, respectively, after the first treatment, and 0.43, 0.30, 0.20, 0.20, and 0.20, respectively, after the second treatment. No significant difference was found in the rate of restenosis for strictures at anastomotic and nonanastomotic sites. Overall, 56 of 75 patients (75%) had successful management with percutaneous therapy.

Following liver transplantation, percutaneous THC is used for treating complications in patients with a duct-to-duct anastomosis and especially in patients in whom hepaticojejunostomy has been performed; these latter anastomoses frequently cannot be accessed via an endoscopic approach. Hepaticojejunal anastomosis is performed at the time of liver transplantation in children, persons with PSC, persons who undergo reoperation for a complication of a duct-to-duct (choledococholedochal) anastomosis, and living-related donors. For treatment of both duct-to-duct and hepaticojejunal anastomotic strictures, percutaneous therapy provides a high nonoperative success rate.^17–19 In addition, in those patients in whom the bile duct is approachable via ERCP but who fail an endoscopic approach, a percutaneous approach is often successful.²⁰

PRIMARY SCLEROSING CHOLANGITIS

Most nonsurgical therapeutic interventions for PSC are now performed via ERCP (see Chapter 68). In the past, percutaneous therapy for a dominant stricture using balloon dilation followed by biliary drain placement for two to three months was found to be highly effective for treating obstructive biliary symptoms in patients with PSC²¹ but less effective in patients with jaundice for more than six months because of liver parenchymal dysfunction. More recently, only case reports of percutaneous therapy for PSC have appeared in the literature.²² In our experience, percutaneous therapy is useful for patients with a dominant stricture that cannot be accessed endoscopically (Fig. 70-3). In these cases, a guidewire or catheter passed percutaneously can be left in the duodenum to facilitate future endoscopic access (see later).

Figure 70-3. Percutaneous therapy for recurrent primary sclerosing cholangitis after liver transplantation. The patient has a hepaticojejunostomy. A, Initial puncture and passage of a guidewire into the jejunum. B, Balloon dilation of right and left hepatic ducts. C, Follow-up cholangiogram with indwelling internal-external biliary catheter.

BILE LEAKS

Bile leaks are almost always postsurgical in etiology and arise from anastomotic (e.g., post-liver transplant) and nonanastomotic sites. The latter include cut surfaces of the liver and bile ducts following hepatectomy and laparoscopic injury. Percutaneous management may include drainage of free bile from the peritoneal cavity and of localized bile collections (bilomas) as well as placement of a biliary catheter above or across the leaking site to allow successful closure in the majority of cases.^23–25

BILE DUCT INJURY

Widespread performance of laparoscopic cholecystectomy has led to an increased frequency of major bile duct injuries (see Chapter 66). Other causes of bile duct injury include bile duct exploration or biliary injury resulting from abdominal surgery or trauma. Percutaneous transhepatic biliary drain placement can be used as primary treatment of the injury or to augment surgical repair. Misra and colleagues²⁶ retrospectively evaluated 51 patients who underwent percutaneous biliary management following laparoscopic cholecystectomy-related bile duct injuries over a 10-year period; 45 had operative repair prior to referral. Overall, 46 of the 51 were initially managed percutaneously, and 5 were managed percutaneously following failed hepaticojejunostomy. Nonoperative percutaneous management with balloon dilation resulted in an overall success rate of 58.8% at a mean follow-up of 76 months.

BILE DUCT STONES

Bile duct stones can be managed percutaneously via cholecystostomy tubes, percutaneous placed drains, or surgical T-tubes. Gallbladder tube or T-tube tracts require approximately six weeks to mature prior to use. In many cases, bile duct stones can be cleared percutaneously by dilating the papilla from an antegrade approach.^27,28 The stones, which may require mechanical fragmentation, are flushed into the duodenum. The percutaneous catheter is replaced for several days and then removed. With this approach, in one study²⁷ stones were removed in 95 of 100 patients. In some cases, particularly in the setting of complex intrahepatic stones, a small-caliber choledochoscope (cholangioscope) can be passed through a mature percutaneous tract. Stones are then fragmented using a variety of techniques, with a high rate of success (see Chapter 65).^29,30

MALIGNANT BILIARY OBSTRUCTION

Stents can be placed percutaneously for relief of malignant biliary obstruction, either preoperatively or for palliation. Stents are composed of either rigid plastic or self-expanding metal. Self-expanding metal stents (SEMS) were designed to avoid occlusion from bacterial biofilm, which invariably occurs in plastic stents and results in the need for re-intervention.

Distal bile duct strictures (e.g., caused by pancreatic head cancer) are preferably managed via ERCP (see later) because endoscopic stent placement is less painful than percutaneous stent placement and is associated with fewer complications. This conclusion is based on a randomized trial of endoscopic and percutaneous approaches using plastic stents.³¹ Percutaneous stent placement can easily be achieved in these patients, however. Multiple interventions are often needed to place plastic stents prior to final internalization of the stent because large-bore (≥10-French) stents require dilation of a tract through the liver, which often cannot be accomplished in one stage. Bleeding, which occurs with such aggressive dilation, often requires maintenance of an external catheter to drain blood within the biliary tree. More recently, SEMS have been used. In a classic study, percutaneous placement of SEMS was associated with significantly longer stent patency, reduction in the need for re-intervention, and shorter hospital stays.³² In addition, advantages of SEMS when placed percutaneously are the availability of small-diameter pre-deployment delivery systems, so that the percutaneous tract does not require dilation, and the capability for stent insertion in one step.^32,33 In a randomized trial³⁴ of endoscopic versus percutaneous palliation of malignant bile duct obstruction in which metal biliary stents were placed percutaneously in one step and plastic stents were placed endoscopically, percutaneous placement of SEMS was associated with a 34% lower rate of recurrent biliary obstruction.

Relief of hilar biliary obstruction (e.g., caused by hilar cholangiocarcinomas, or Klatskin tumors) is more difficult to achieve endoscopically than relief of distal bile duct obstruction. Several studies have suggested that the percutaneous approach to these tumors is superior to the endoscopic approach, with a lower rate of post-procedure cholangitis.^34,35

Covered SEMS were designed to improve stent patency by reducing the frequency of occlusion resulting from tumor ingrowth and tissue hyperplasia. Studies have shown promising results,^36,37 although no randomized trials of covered versus uncovered stents placed via the percutaneous approach have been published.