Direct cholangiography: Approaches, techniques, and current role

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Chapter 18 Direct cholangiography

Approaches, techniques, and current role

Direct Cholangiography Overview

Direct cholangiography, the introduction of contrast medium into the biliary system, can be achieved radiologically, endoscopically, or intraoperatively via surgically placed tubes. The nonoperative techniques are percutaneous transhepatic cholangiography (PTC) and endoscopic retrograde cholangiopancreatography (ERCP). Currently, noninvasive magnetic resonance imaging (MRI) and computed tomographic (CT) cholangiography have virtually eliminated the indications and need for direct cholangiography (Stroszczynski & Hünerbein, 2005; Miller et al, 2007; Bakhal et al, 2009; see Chapters 16 and 17). Today ERCP and PTC are almost exclusively performed only as part of a planned interventional procedure, such as drainage, stenting, stone extraction, or stricture dilation (see Chapters 27 and 28).

The most obvious benefits of noninvasive cholangiography are that it is painless, does not require sedation, and has few complications. Thin-section scanning techniques with multiplanar reconstruction allow for a large field of view that enables visualization of the entire biliary tree (Fig. 18.1). Reconstructed three-dimensional data sets can be displayed as a cholangiogram and manipulated in space. By contrast, direct dye injection only allows visualization of the structures in continuity with the opacified, nonisolated segments of the biliary system (Fig. 18.2). In PTC, even with multiple puncture sites and injections, simultaneous cross-sectional imaging may be required to ensure that the entire biliary tree has been opacified. In addition, noninvasive cholangiography has overall superior diagnostic accuracy compared with invasive techniques, allowing for visualization of structures contiguous to the biliary system and the bile duct wall.

Percutaneous Transhepatic Cholangiography (See Chapter 28)

History

The first report of radiologic visualization of the biliary tree was presented by Burckhardt and Müller in 1921, and cholecystocholangiography was achieved by percutaneous puncture of the gallbladder. The first report of PTC was by Huard and Do-Xuan-Hop in 1937, and cholangiography was performed with the suboptimal contrast agent Lipiodol. The use of transhepatic cholangiography as a diagnostic tool gained popularity 15 years later, after Carter and Saypol’s (1952) discussion of PTC with the use of a water-soluble contrast agent. In the ensuing years, many investigators (Flemma & Shingleton, 1966; Glenn et al, 1962; Mujahed & Evans, 1966; Seldinger, 1966; Shaldon et al, 1962; Weicher, 1964) described a variety of different methodologic details, including the use of sheathed or unsheathed needles of various sizes, different sites and directions of puncture, and various numbers of puncture trials to maximize success. The procedure remained associated with a significant risk of bile peritonitis, especially in obstructed systems, and the less frequent complication of hemorrhage. The last essential refinement in transhepatic cholangiography, the use of fine needle technique, was developed at Chiba University and was first presented by Ohto and Tsuchiya (1969) and later by Tsuchiya (1969). The value and decreased complication rate of the fine needle technique was verified by numerous authors (Benjamin et al, 1978; Ferrucci et al, 1976; Fraser et al, 1978; Gold & Price, 1980; Harbin et al, 1980; Hinde et al, 1977; Jain et al, 1977; Pereiras et al, 1977), and the fine needle technique has been generally accepted as the standard.

At present, diagnostic transhepatic cholangiography has been completely supplanted by noninvasive imaging techniques for the evaluation of the biliary tree. In 1985, Kadir reported that less than 5% of patients referred for evaluation of biliary disease required concomitant drainage procedures. With continued advancement of cross-sectional imaging techniques, including the development of MRI cholangiography (Park et al, 2004; Romagnuolo et al, 2003; Simone et al, 2004; Vaishali et al, 2004; Zhong et al, 2003) and CT cholangiography, diagnostic PTC should be performed only as part of a planned radiologic interventional procedure.

The most obvious benefits of noninvasive cholangiography are the elimination of complications and pain, but several other advantages are also important. Puncture and contrast injection techniques in high bile duct obstruction with isolated systems visualize only the portions of the biliary tree that are in continuity with the puncture site, and multiple interventions may be required to visualize the entire biliary tree if there are areas of duct isolation (see Fig. 18.2). Even with multiple punctures and contrast injections, cross-sectional imaging may be necessary sometimes to ensure that the biliary tree has been completely assessed. MRI cholangiography has the advantage of showing the entire biliary system even in the presence of isolation (see Fig. 18.1). Finally, there is the diagnostic advantage gained with cross-sectional imaging. By allowing visualization of many more organs than just the biliary system, diagnostic accuracy of cholangiography is significantly increased.

Procedure

The procedure is ideally performed on a tilting fluoroscopic table. Because the specific gravity of contrast material is greater than that of bile, when the fluoroscopic table can be tilted, less contrast agent is required to fully delineate the biliary tree.

Right-Sided Puncture

After the patient has been prepared and draped in a sterile fashion, a puncture site is selected in the right midaxillary line one or two interspaces below the costophrenic angle. Puncture sites are generally kept below the ninth intercostal space to avoid inadvertent entry into the pleural space. A 21- or 22- gauge, 15- to 20-cm styletted needle is advanced under fluoroscopic guidance over the rib, rather than under, to avoid laceration of an intercostal vessel. The puncture is performed neither from a particular intercostal space nor aiming at a particular vertebra, rather the site and direction of puncture are chosen based on evaluation of the patient’s cross-sectional imaging studies.

Care should be taken to avoid puncture of the gallbladder or extrahepatic biliary tree. A small amount of water-soluble contrast agent is injected while slowly withdrawing the needle until a bile duct is identified. Injection of contrast agent into a bile duct has the appearance of oil being dropped in water. Inadvertent opacification of a vascular structure is recognized by the rapid clearance of the contrast agent. If a bile duct is not entered during withdrawal of the needle, the needle is reintroduced in a slightly different direction. It is generally recommended, however, that the needle not be withdrawn completely from the liver to minimize damage to the liver capsule. When opacification of the biliary tree is difficult, particularly when the ducts are not dilated, the same puncture site may be used up to 12 times before a new intercostal space is selected for needle placement. In patients with biliary obstruction, 10 to 20 mL of contrast agent injected slowly is usually sufficient to opacify the bile ducts. The use of a tilting table is valuable to avoid biliary tree overdistension, which could lead to bacteremia or sepsis. A larger volume of contrast material is often required in nonobstructed systems. When the bile ducts are visualized, radiographs should be obtained in multiple projections to identify specific portions of the biliary tree and to completely delineate abnormal findings.

Success Rate and Accuracy

Opacification of the bile ducts is successful in 95% to 100% of patients with biliary obstruction (Mueller et al, 1981; Harbin et al, 1980; Jain et al, 1977). A success rate of 60% to 95% is reported for nondilated biliary systems. The chance of success in the nondilated system is increased by the number of needle passes performed (Jaques et al, 1980). Usually, the level of obstruction is accurately determined by careful attention to detail and liberal use of a tilt table, but the technique is less definitive for determining the cause of obstruction. No radiologic descriptions of obstructed bile ducts are pathognomonic for differentiation of benign and malignant disease (Hadjis et al, 1985; Wetter et al, 1991). Many malignant masquerades are well described, and it is not always possible to differentiate between calculous disease and papillary bile duct cancer. Other radiologic findings and cytology or histology are often required for accurate diagnosis.

Complications

Serious complications of PTC are rare and occur in approximately 3% of patients (Harbin et al, 1980). The most common major complications are bile leakage (1% to 2%), sepsis (2% to 3%), and hemorrhage (0.2% to 0.4%); much rarer complications include pneumothorax, biliothorax, colon puncture, and abscess formation. Many of these complications can be decreased and avoided. Ultrasound guidance and puncture below the ninth intercostal space will clearly decrease the incidence of pulmonary complications, and septic complications can be avoided by appropriate antibiotic coverage and by not overdistending the biliary tree. At times, aspiration and decompression of the biliary tree will be valuable in allowing injection of larger volumes of contrast agent without leading to sepsis.

Endoscopic Retrograde Cholangiopancreatography (See Chapter 27)

History

ERCP was first reported in 1968 by McCune and colleagues and has remained an important diagnostic modality frequently used in the management of patients with hepatobiliary and pancreatic diseases (Cotton, 1977; Cotton et al, 1972; Freeney, 1988; Oi et al, 1970). Since the 1970s, there has been continued progress in ERCP instrumentation. One major innovation was the development in the late 1980s of video, or electronic, endoscopy. Video endoscopy enables high-quality photographic and videotape documentation of important endoscopic findings and has made the training of physicians in the technique of ERCP much easier. The endoscopic skills needed to perform ERCP are more difficult to learn than the standard procedures of upper endoscopy and colonoscopy, but now many endoscopists throughout the world can perform diagnostic ERCP easily, rapidly, and safely. Working with a cooperative patient and a well-trained team, this procedure often can be completed in less than 15 minutes. Diagnostic ERCP is rapidly being replaced, however, by noninvasive imaging techniques, such as MRCP.

A 2002 National Institutes of Health consensus conference on ERCP concluded that although MRCP and ERCP had similar sensitivity and specificity in diagnosing common bile duct stones, ERCP, as an invasive procedure, is more operator dependent and has risks associated with it because of the required sedation, and it carries the risk of injection pancreatitis. As a result, stand-alone diagnostic ERCP is being used much less frequently. It is most commonly combined with a therapeutic endoscopic procedure, such as endoscopic sphincterotomy and stone extraction for choledocholithiasis, or the insertion of an endobiliary stent for malignant biliary obstruction.

Technique

Patient selection is important, because ERCP is commonly done in an outpatient setting. Patients should be alert and oriented and must be able to give informed consent. In the rare situation in which this is not possible, such as with an intubated patient on mechanical ventilation, consent is obtained from the next of kin. Patients with uncorrected shock, cardiac arrhythmias, profound neutropenia, or significant coagulopathy should not have an elective diagnostic test such as ERCP performed.

Age is not a contraindication to ERCP, because the procedure is safe even for selected patients in their 90s. Although children less commonly have pancreatic and biliary disease, the standard technique is often all that is necessary for children, and instrumentation is the same except in children younger than 6 months old. General anesthesia is rarely needed for children older than 11 or 12 years (Buckley & Connon, 1990). ERCP has been shown to be a valuable adjunct in the evaluation of infantile cholestasis (Wilkinson et al, 1991). In a case-control study comparing children undergoing ERCP with adults, there were no differences in the success rate or the rate of complications (Varadarajulu et al, 2004). Elderly patients can safely undergo ERCP, and they have the same risks of bleeding and perforation as younger patients do but have a lower risk of pancreatitis.

Patient comfort is maintained by the use of intravenous sedation under monitored control. Drug combinations include narcotics such as meperidine and droperidol and the benzodiazepines midazolam or diazepam. Dosages are titrated for each patient with a total dose of meperidine generally ranging from 50 and 100 mg and midazolam between 2 and 10 mg. More recently, propofol, at 190 μg/kg/min, administered by anesthesia personnel, has been replacing meperidine and a benzodiazepine. Studies have shown that propofol is more effective than sedation with midazolam, it is safe, and it is associated with a faster postprocedure recovery (Wehrman et al, 1999). In some centers, if the endoscopic procedure is expected to be difficult, or if the patient has significant comorbid medical conditions, general anesthesia is used. Excess duodenal motility is controlled by bolus injections of 0.2 to 1 mg of intravenous glucagon. Oxygen is administered by nasal cannula to avoid the hypoxemia that has been described in 40% of patients undergoing ERCP (Woods et al, 1989). The patient’s electrocardiogram, blood pressure, oxygen saturation, and overall condition are continually monitored throughout the procedure by a dedicated nurse. Antibiotics are not given routinely for diagnostic procedures except when biliary obstruction is expected. All endoscopic equipment used for this procedure, including the endoscopes, is either chemically disinfected or gas sterilized.

A side-viewing duodenoscope is used to afford excellent visualization of the ampulla of Vater. In patients with a Billroth II type gastrojejunostomy, a standard forward-viewing upper endoscope or pediatric colonoscope may be needed to successfully approach the ampulla. An initial endoscopic evaluation of the stomach and duodenum is performed before cannulation of the ampulla. The pancreatic and biliary ducts are selectively cannulated and identified, and a contrast agent, such as diluted Renografin-60, is injected into the desired duct under fluoroscopic control, with subsequent radiographic images obtained of the duct anatomy. The use of a guidewire to cannulate the ampulla without using contrast is becoming common. In one recent series, 795 (99%) of 801 ERCPs were performed without contrast to initially identify access to the common bile duct (CBD). The pancreatitis rate in this series was 1.3%, as was guidewire perforation of the bile duct, which also occurred infrequently (Adler et al, 2010). An additional way of gaining access to the difficult-to-cannulate CBD is to selectively place a pancreatic duct stent first and then attempt wire-guided cannulation of the bile duct.

Material for pathologic and cytologic evaluation can be obtained from either the biliary or pancreatic duct system with a variety of dedicated endoscopic biopsy forceps and cytology brushes. Pathologic and cytologic material also may be obtained from the ampulla of Vater, duodenum, and stomach.

A skilled endoscopist can be expected to identify the ampulla of Vater in almost all patients with normal anatomy. If the ampulla is inside a duodenal diverticulum, or if the second portion of the duodenum is stenotic, compressed, or invaded by a pancreatic mass, identification of the ampulla may be difficult. When the ampulla is found, success rates for selectively cannulating the CBD and pancreatic duct are greater than 90% (Rosch, 1985). When difficulty occurs in cannulation of the CBD, invasive maneuvers, such as precut papillotomy, can improve the success rate but with an associated increase in the complication rate (Shakoor & Geenen, 1992). In a patient with a Billroth II gastrojejunostomy, success rates for bile duct cannulation are much lower (Katon et al, 1975; Osnes & Myren, 1975).

Endoscopy and Pancreatography during Endoscopic Retrograde Cholangiopancreatography

The ability to perform endoscopy and pancreatography in addition to cholangiography during ERCP affords a major advantage to this procedure. It is common for endoscopic examination of the stomach and duodenum to provide important diagnostic information that is helpful in management planning. Displacement of the antrum or pylorus or a stricture or narrowing of the second portion of the duodenum may indicate the presence of a pancreatic mass responsible for obstructive jaundice. The diagnosis can be confirmed by biopsy and cytologic specimens taken during the procedure from the infiltrated or ulcerated duodenal wall.

Duodenal diverticula almost always are located near the papilla in the descending duodenum. Large juxtapapillary diverticula are clinically significant, because they are often associated with choledocholithiasis. Although it was thought that periampullary diverticula may make cannulation of the ampulla more difficult, more recent work has shown that this may not be true (Tham & Kelly, 2004). On inspection of the ampulla, anatomic variants should be looked for before attempting cannulation (Phillip et al, 1974). Occasionally, two orifices are found, and this indicates separate biliary and pancreatic duct systems. The minor ampulla is located about 1 to 2 cm above the major papilla. Impacted gallstones give rise to a characteristic distension or bulge of the papilla, and previous spontaneous passage of bile duct stones can be recognized by a fissured splitting of the papillary orifice. Previous surgical dilation of the papilla or spontaneous gallstone perforation above the papilla also produces a characteristic appearance. Occasionally, a fistulous perforation in the roof of the papilla is found as a result of a false passage produced at surgical dilation (Tanaka & Ikeda, 1983). Biliary–enteric anastomoses appear as circular or slitlike openings.

The endoscopic diagnosis of ampullary carcinoma is not difficult, especially if the tumor is exophytic. The diagnosis becomes more challenging, however, when the tumor is predominantly intramural. In such instances, the diagnosis is frequently confirmed by biopsy and cytologic specimens, after endoscopic papillotomy allows the tumor to be exposed. In a series from the Medical College of Wisconsin, the correct diagnosis was made by endoscopic biopsy in 42 of 44 patients with ampullary neoplasia and in 16 of 18 patients with invasive ampullary cancer (Komoroski et al, 1991).

Imaging the pancreatic duct can be an important adjunct to cholangiography during ERCP. Strictures, stones, and other obstructing lesions can be identified. With increasing age comes progressive atrophy and fibrosis of the pancreas. The diameter of the main pancreatic duct also increases with age, although one study found no difference in pancreatic duct length among patients younger than 40 years compared with older patients. Duct diameter throughout the pancreas was significantly greater, however, in patients over 40 (Anand et al, 1989).

Anatomic variations, such as pancreas divisum (Fig. 18.4), also may be identified on a pancreatogram. This abnormality has been described in 7.5% of ERCP procedures and can be confirmed by cannulation of the main pancreatic duct through the orifice in the minor papilla (Bernard et al, 1990).

Complications

The experience of the endoscopist is one of the most significant factors related to the development of ERCP complications (Bilbao et al, 1976). Statistics on complication rates vary accordingly. High case volume also has an impact on the complication rate. In a study conducted in Austria, endoscopists performing more that 50 ERCP procedures per year were compared with on those performing fewer than 50 per year. Those in the higher case volume group had a significantly higher success rate (86.9% vs. 80.3%; P < .001) and a lower overall complication rate (10.2% vs. 13.6%, P = .007; Kapral et al, 2008).

Acute pancreatitis after ERCP occurs in less than 7% of patients (Christensen et al, 2004; Rosch et al, 1981) and should be distinguished from transient asymptomatic hyperamylasemia, which occurs in 40% to 75% of cases (Classen & Demling, 1975). Asymptomatic hyperamylasemia disappears within 1 to 2 days, as do hypertrypsinemia (Phillip & Hagenmuller, 1983) and elevations of serum lipase and elastase 1 levels (Okuno et al, 1985). Radiographic documentation of renal excretion of the contrast agent injected into the pancreatic duct does not predict the development of acute pancreatitis (Hopper et al, 1989), and necrotizing pancreatitis, a serious complication, is observed in about 0.1% of pancreatograms. The prevalence of post-ERCP pancreatitis in children is quite low, about 2.5% in one study (Iqbal et al, 2008).

The use of nonionic contrast medium of low osmolarity has shown no advantage over the less expensive ionic contrast medium in preventing ERCP-related pancreatitis (Hannigan et al, 1985). The risk of pancreatitis is reduced by careful and gentle injection of the contrast medium into the pancreatic duct, by avoiding overdistension or “acinarization” of the pancreatic duct, and by minimizing repeated injection of the pancreatic duct when encountering difficulty in filling the CBD. Prophylactic administration of somatostatin or its analog octreotide has not been shown to prevent pancreatitis during diagnostic or therapeutic ERCP (Borsch et al, 1984; Sternlieb et al, 1992). A large, prospective, randomized, placebo-controlled study from Italy looked at the efficacy of somatostatin and gabexate in preventing post-ERCP pancreatitis; 966 patients were studied, and no difference in the rate of pancreatitis was observed between the groups (Andriulli et al, 2004). A randomized control study demonstrated that 24 hours of octreotide prophylaxis before ERCP significantly decreased the incidence of post-ERCP pancreatitis compared with a placebo group (2/100 [2%] vs. 9/101 [8.9%]; P = .03) (Thomopoulos et al, 2006). Other investigators have suggested that when injection pancreatitis is a possibility, the use of a temporary pancreatic duct stent may serve to prevent its occurrence (Singh et al, 2004). In addition, when pancreatitis has developed, the use of somatostatin does not improve its clinical course (Phillip et al, 1985).

A serious complication of ERCP is the development of postprocedure cholangitis. This condition occurs most commonly when there is a significant and high-grade bile duct obstruction. When an obstructed bile duct is identified on ERCP, it is important to treat the obstruction rapidly by nonsurgical or surgical means (Classen & Phillip, 1982). Although no studies confirm the benefit of prophylactic antibiotics, it is reasonable to administer intravenous antibiotics that are preferentially excreted from the liver into the bile until adequate biliary drainage is achieved.

One study looked at the prophylactic use of antibiotics in routine ERCPs (Sauter et al, 1990

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