Introduction

Although almost all endoscopic retrograde cholangiopancreatography (ERCP) is undertaken with a view to a therapeutic intervention, an understanding of the basic concepts is essential before progressing to therapeutic ERCP. This chapter is divided into two sections. The first section introduces the basic techniques required to selectively cannulate the common bile duct or pancreatic duct, as well as the equipment required for ERCP; how to ensure that you obtain the optimum images from the procedure; and what pitfalls to watch out for in image interpretation. The second part of the chapter discusses therapeutic procedures and the complications associated with ERCP.

Introduction

In addition to the usual medications used for sedation (see Ch. 2.3 ), glucagon and secretin are sometimes use to aid identification of the major or minor papillae or assist cannulation.

1

Glucagon

Glucagon causes transient relaxation of the smooth muscles of the GI tract, thus decreasing motility. Glucagon has an onset of action of 1 min, with a duration of effect of 20–30 min. It should be avoided in patients undergoing sphincter of Oddi manometry.

2

Secretin

Secretin causes stimulation of pancreatic secretions and can be used to facilitate identification of the ampulla of Vater and the accessory papilla. Secretin has a rapid onset of action, with levels returning to baseline within 90 min.

Introduction

In addition to the usual medications used for sedation (see Ch. 2.3 ), glucagon and secretin are sometimes use to aid identification of the major or minor papillae or assist cannulation.

1

Glucagon

Glucagon causes transient relaxation of the smooth muscles of the GI tract, thus decreasing motility. Glucagon has an onset of action of 1 min, with a duration of effect of 20–30 min. It should be avoided in patients undergoing sphincter of Oddi manometry.

2

Secretin

Secretin causes stimulation of pancreatic secretions and can be used to facilitate identification of the ampulla of Vater and the accessory papilla. Secretin has a rapid onset of action, with levels returning to baseline within 90 min.

1

Patient checklist

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  Patient preparation (see Chapters 2.1, 2.2 and 2.3 )

  
  
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  Admission notes

  
  
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  Previous imaging

  
  
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  Liver function tests (AST, ALT, GGT, alkaline phosphatase, and bilirubine)

  
  
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  Pancreatic tests (amylase and lipase)

  
  
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  Anaesthetic review

  
  
• •
  

  Informed consent

  
  
• •
  

  INR, platelets

  
  
  
  
  • ▪
    

    Usually only required in patients with evidence of a bleeding disorder, liver disease, malnutrition, prolonged therapy with antibiotics associated with clotting factor deficiencies, prolonged biliary obstruction or in patients who are receiving anticoagulation therapy

  
  
  
  
• •
  

  Venous access in right arm

  
  
• •
  

  Antifoam solution is sometimes given prior to the procedure.

2

Endoscopist checklist

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  Check that the endoscope is aspirating, blowing air and water correctly, and that white balancing has been performed

  
  
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  Make sure that endoscopy recording equipment is available and working.

3

Patient positioning

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  The patient is placed in the left lateral decubitus position with their left arm at their back

  
  
• •
  

  Patients should preferably be placed in a supine position, if access to the minor papilla is required or in cases of hilar stenosis, to allow optimal visualization of the biliary tree.

1

Inserting the duodenoscope and positioning over the papilla

How to intubate and position the duodenoscope in front of the papilla is illustrated in Figure 1 . Gently insert the duodenoscope to the upper esophageal sphincter. The esophagus is intubated blindly with gentle forward pressure and slight clockwise rotation. If there is resistance STOP, and change to a forward viewing gastroscope to exclude anything which may cause difficulties with intubation (i.e. Zenker’s diverticulum/stricture). Due to the side-viewing nature of the duodenoscope, a full view of the esophagus is not possible. Once the duodenoscope passes the gastroesophageal junction, make a half turn clockwise and follow the lesser curve to the pylorus. As the duodenoscope is side viewing, the duodenum is entered by placing the pylorus in the ‘setting sun’ position, so that the upper half of the pylorus is visible at the 6 o’clock position. Check that the shaft of the scope is at the 12 o’clock position when intubating the pylorus as this ensures optimum positioning in front of the papilla. The duodenoscope is then inserted into the second part of the duodenum. Two maneuvers are performed in succession: first turn the big wheel anticlockwise and the small wheel clockwise, thus deflecting the tip of the scope up and right, then withdraw the endoscope to 50–70 cm from the incisors to reduce the gastric loop.

Inserting the duodenoscope and positioning over the papilla. (A) Duodenoscope advancing blind into the esophagus. (B) Advancing along the lesser curvature. (C) The endoscope rests on the greater curvature and faces the pylorus. (D) Deflection upwards, before advancing through the pylorus. (E) The apparatus advances to the superior flexure. (F) The endoscopist turns to his right through 90°. (G) The endoscopist has turned to his right through 90°. (H) Deflection upwards and to the right by turning the small wheel clockwise and the big wheel anti-clockwise. (I) Withdrawal of the endoscope to approximately 70 cm which removes the gastric loop.

2

Locating the papilla

The major papilla should now be in the field of vision. The major papilla consists of a frenulum, a hood, infundibulum, and orifice ( Fig. 2 ). It is often a different color from the rest of the duodenum. The papilla should be inspected for evidence of stone passage (gaping or inflamed orifice), edema or papillary adenoma. The major papilla is then classified depending on its appearance ( Fig. 3 ). This is important when assessing how far a sphincterotomy may be extended and to do a diathermic puncture of biliary infundibulum.

Normal papilla. (1) Papillary orifice. (2) Frenulum. (3) Hood. (4) Infundibulum.

Classification of the various types of infundibulum. Type 0: no infundibulum. Type 1: the infundibulum extends to the limit of visibility. Type 2: a prominent infundibulum. Type 3: a large infundibulum which covers the papilla.

2.2

Locating the minor papilla

The minor papilla is smaller ( Fig. 5 ), and is usually located 2 cm proximal and anterior to the major papilla in the second part of the duodenum. It can be difficult to locate. In these cases consider the following:

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  Use a long scope position: this is usually the optimum position to see the minor papilla

  
  
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  Place the patient in the supine position

  
  
• •
  

  Give secretin. Some authors recommend spraying the second portion of the duodenum prior to giving secretin.

Minor papilla (arrow).

3

Cannulating the major papilla

Flush the catheter or sphincterotome with dye prior to commencing the procedure to prevent any injection of air. Prior to attempting cannulation, optimize conditions and ensure there is an adequate view of the papilla by ensuring:

• •
  

  Duodenal hypotonia: give glucagon if necessary

  
  
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  No bubbles or mucus: use antifoam solution (simethicone)

  
  
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  Take time to optimally position the duodenoscope and ensure that the orifice is at the center of the image

  
  
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  Wait a little for the orifice to open.

3.1

Cannulating the bile duct and pancreatic duct

To selectively cannulate the bile duct, the side-viewing duodenoscope should be placed below the major papilla. Place the catheter slightly below the papilla and direct the catheter vertically towards 11–12 o’clock ( Fig. 6 ) in the right upper quadrant. Cannulation of the pancreatic duct requires the duodenoscope to be placed en-face , and slightly to the left of the papilla. The catheter should be placed on the right side of the papilla between 1 and 3 o’clock, with the catheter moving from left to right. If the os is difficult to catheterize, the catheter can initially be introduced a few millimeters, then directed towards the biliary or pancreatic orifice. The catheter is then introduced as far as possible into the chosen duct.

Orientation of the pancreatic and bile duct. Using the face of a clock for orientation, the pancreatic duct is found between 1 and 3 o’clock position, while the bile duct is found at 11 o’clock.

In obese patients, those with malignant pancreatic disease, particularly where there is a lesion in the genu of the pancreas, it can be difficult to properly centre the major papilla. In these cases, a long scope position may be required, and the endoscopist may need to position themselves in the opposite of the classic position (i.e. at 90° to the patient’s face).

Box 2

Role of a guidewire

• •
  

  A wire allows the sphincterotome to be manipulated (i.e. withdrawn to just above the ampulla) without losing cannulation. This is very useful for people learning ERCP or after a difficult cannulation. It is also useful when the papilla is difficult to cannulate (i.e. stenotic os).

  
  
• •
  

  It can be useful to determine whether the correct duct has been cannulated, thus avoiding repeated injection of contrast into the pancreatic duct. This is done by looking at the direction the wire follows (see Clinical Tip ‘How do I know which duct I am in’ below).

  
  
• •
  

  The guidewire is also very useful where minimizing contrast injection is important, e.g. in a patient with cholangiocarcinoma.

Clinical Tip

How do I know which duct I am in?

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  Depth of duct cannulation:

  
  
  
  
  • ○
    

    Deep duct cannulation is usually associated with bile duct cannulation

    
    
  • ○
    

    Intermediate duct cannulation usually occurs after cannulating the pancreatic duct as the catheter comes up against the genu of the pancreatic duct.

  
  
  
  
• •
  

  Aspiration:

  
  
  
  
  • ○
    

    Aspiration of yellow bile or colourless pancreatic juice helps to determine which duct the catheter is in without injecting it.

  
  
  
  
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  Wire direction:

  
  
  
  
  • ○
    

    The direction of the guidewire can be used to confirm which duct has been cannulated. The wire should advance towards the diaphragm, moving towards 11 o’clock, when the bile duct is cannulated. The guidewire initially moves towards 1 o’clock followed by the 3 o’clock position if the pancreatic duct is cannulated.

  
  

4

Failure to cannulate the desired duct

• •
  

  Check that the catheter is in the correct orientation to cannulate the desired duct:

  
  
  
  
  • ▪
    

    Use fluoroscopy to check the position of the endoscope and the direction of the catheter. To cannulate the bile duct, check that the tip of the endoscope is slightly under the papillary orifice, with the catheter pointing towards 11 o’clock ( Fig. 7 ). For the pancreatic duct, the tip of the endoscope should be placed in the same area as the papillary orifice, with the catheter directed towards 1–3 o’clock ( Fig. 7 ).

  
  
  
  
• •
  

  The pancreatic and biliary orifices are separate:

  
  
  
  
  • ▪
    

    If the pancreatic duct is repeatedly cannulated, look above the cannulated orifice for the biliary orifice.

  
  
  
  
• •
  

  The catheter is in the correct direction for the bile duct, but deep cannulation cannot be achieved:

  
  
  
  
  • ▪
    

    This is because the catheter is up against the anterior wall of the ampulla or the common bile duct. Withdraw the endoscope slightly: when the papilla has disappeared from the visual field, push the catheter forward into the bile duct.

  
  
  
  
• •
  

  Use a hydrophilic guidewire to cannulate the desired duct ( Fig. 8 ).

  
  

  
  

  
  

  

  
  

  
  

  Selective cannulation with a wire. A wire can be used to selectively cannulate either the bile duct. (A) Note the position of the duodenoscope below the papilla or the pancreatic duct. (B) Once the correct duct has been cannulated with the guidewire, the sphincterotome is then inserted over it.

  
  
  
  
• •
  

  Change the catheter to a sphincterotome:

  
  
  
  
  • ▪
    

    The sphincterotome can be tensed, which allows for maximum elevation to assist biliary cannulation.

  
  
  
  
• •
  

  The papilla is stenotic:

  
  
  
  
  • ▪
    

    A tapered catheter or sphincterotome is sometimes useful.

  
  
  
  
• •
  

  If the pancreatic duct is repeatedly entered, a wire can be left in the pancreatic duct. This prevents further pancreatic duct cannulation. It also identifies the direction of the pancreatic duct. Once this is known, the direction of the bile duct can be determined. Alternatively, a pancreatic duct stent can be inserted, with subsequent cannulation of the common bile duct.

  
  
• •
  

  Cholecystokinin can sometimes be used. This causes the gallbladder to empty with subsequent opening of the papillary orifice.

Needle knife pre-cut sphincterotomy should not be used to access the biliary or pancreatic duct, except in an emergency. If the above maneuvers fail, the procedure should be discontinued and a repeat attempt made 24–48 h later. This allows the edema to settle, and the second procedure is often successful.

5

Cannulating the papilla beside a diverticulum

Diverticulae frequently occur in the second part of the duodenum, especially in elderly individuals. In these cases, look for the papilla at the edges or inside the diverticulum ( Fig. 9 ). Occasionally it is hidden by the duodenal folds, which should be lifted using a catheter. If the papilla cannot be identified, identify the frenulum and hence the papilla. Cannulating a papilla located at the edge, inside or in the middle of a diverticulum is usually possible. The difficulty arises when the papilla is located inside the diverticulum and with the os also facing towards the inside of the diverticulum. In these cases, the following can be tried:

• •
  

  Evert the papilla by pressing with a catheter on the edge of the diverticulum without insufflating it too much.

  
  
• •
  

  Saline has been used raise the papilla from the diverticulum ( Fig. 10A,B ); however, this can be associated with pancreatitis.

  
  
• •
  

  Gently tease the papilla outside the diverticulum with a biopsy forceps ( Fig. 10C ).

  
  

  
  

  
  

  

  
  

  
  

  Techniques for accessing a papilla located within a diverticulum. Saline can be injected (A) which raises the papilla from the diverticulum (B). However, this is associated with an increased risk of pancreatitis. Biopsy forceps can also be used to tease the papilla out of the diverticulum (C).

  
  
  
  
• •
  

  It is sometimes possible to place the tip of the endoscope into the diverticulum to center it.

  
  
• •
  

  Percutaneous transhepatic wire can be inserted through the ampulla (see section 8.11).

Location of papilla in the presence of a diverticulum. The papilla is located at the left (A) or right (B) edge of a large diverticulum. This is the most common presentation. (C) Papilla between two small diverticula. (D) Papilla in the centre of large diverticulum.

6

Cannulating a stricture

Traversing a difficult stricture requires patience, skill and optimum X-ray control. When a difficult stricture is encountered the following should be tried:

• •
  

  Consider using a fully hydrophilic wire for difficult strictures ( Fig. 11 ). Also an angled tip is sometimes useful. Repeat forward and back movements while simultaneously twirling the wire. Occasionally, a 0.025 or 0.018 inch guidewire is needed. An ultratapered sphincterotome or cure-tipped 5–6 Fr cannula may also be useful. Once the stricture has been traversed, the sphincterotome is advanced across the stricture and the guidewire should be exchanged for a regular guidewire as this facilitates dilation or stent placement.

  
  

  
  

  
  

  

  
  

  
  

  Inserting a guidewire through a stricture. Strictures should be crossed initially using a guidewire. If the guidewire is hitting the side walls (A,B), withdraw the sphincterotome slightly (C). This maneuver allows optimal alignment of the guidewire with the stricture.

  
  
  
  
• •
  

  The left hepatic duct is usually more difficult to cannulate. Bounce the guidewire off the lateral wall to cannulate the left hepatic duct. A swingtip or Haber Ramp catheter is occasionally useful in difficult cannulation.

  
  
• •
  

  Cannulate the right hepatic duct by placing the sphincterotome at the level of the bifurcation and direct towards the right hepatic duct.

  
  
• •
  

  Distortion of the second part of the duodenum by tumour can hinder the correct centering of the papilla. If cannulation of the papilla is difficult, determine if this is a technical problem or a low stenosis. Review pre-ERCP imaging (ideally MRC or EUS) to determine whether there is a low stenosis near the papillary orifice. In this case, use a sphincterotome mounted on a guidewire to find the orifice of the stenosis. Pre-cut sphincterotomy or diathermy loop excision of the infundibulum may be necessary.

  
  
• •
  

  Make a loop with the guidewire ( Fig. 12 ). Once the loop moves in the desired direction, advance the sphincterotome over the guidewire to the apex of the loop. Then withdraw the guidewire until the wire is straight. Reinsert the guidewire, forming a loop if necessary. This is repeated until the stricture is traversed.

  
  

  
  

  
  

  

  
  

  
  

  How to manipulate the wire into the correct hepatic duct. (A) Produce a loop with the guidewire. (B) Insert the catheter to the end of the loop. (C) Undo the loop formed by the guidewire. (D) Insert the guidewire through the catheter lying in the correct direction. Withdraw the guide catheter to change the direction of the guidewire if the guidewire fails to pass through the stenosis.

  
  
  
  
• •
  

  Advance stepwise if the stenosis has several angulations. The guidewire is advanced to the end of the first angulation ( Fig. 13A ). The sphincterotome is advanced over the guidewire to this point ( Fig. 13B ). The guidewire is advanced to the end of the second angulation, followed by the sphincterotome ( Fig. 13C ). This is repeated until the stricture is crossed ( Fig. 13D ).

  
  

  
  

  
  

  

  
  

  
  

  Inserting a guidewire through a complex stricture. The guidewire is advanced in a stepwise manner. The guidewire is advanced to the end of the first angulation (A). The sphincterotome is advanced over the guidewire to this point (B). The guidewire is advanced to the end of the second angulation, followed by the sphincterotome (C). This is repeated until the stricture is crossed (D).

  
  
  
  
• •
  

  Changing the patient position can help. For complex hilar strictures, placing the patient in the dorsal decubitus position is often useful.

  
  
• •
  

  Placing an inflated retrieval balloon below the stricture can stretch the bile duct and alter the angle aiding guidewire cannulation.

7

Cannulating the minor papilla

The accessory or minor papilla is usually located 2 cm proximal and anterior to the major papilla in the second part of the duodenum. The os is often very small (2 mm), with the duct of Santorini running from the 5 o’clock to the 11 o’clock position. The easiest position to cannulate the minor papilla is in the ‘long’ scope position, with the patient supine. Patience is essential. Wait for the orifice to open before attempting cannulation. Cannulation is usually performed initially with wire, following with the sphincterotome once the duct has been cannulated. This is usually possible with a regular sphincterotome, however a tapered sphincterotome can be required if the os is very small or stenosed. Care should be taken to avoid submucosal injection. If the minor papilla is difficult to locate or cannulate, placing the patient in the supine position is often useful helpful. Secretin can be used to aid identification and to encourage the os to open.

8

ERCP in patients with altered anatomy

8.2

Which endoscope to use?

A duodenoscope is usually used where possible, as the presence of the elevator facilitates cannulation. In addition, the side viewing assists location of the ampulla ( Fig. 14A ). However, it is sometimes not possible to reach the papillary area due to the length of the afferent loop. In these cases, a forward viewing scope should be used. Reaching the ampulla is often successful with a forward viewing scope; however, the ampulla can be more difficult to visualize ( Fig. 14B ), and the lack of an elevator can make cannulation or exchanging over a guidewire difficult. The choice of forward viewing scope depends on what is available in the unit and the experience of the endoscopist. Options include a pediatric colonoscope, a single or double balloon enteroscope, or an enteroscope with Spirus overtube. Where a forward-viewing endoscope is used, but cannulation has failed, it is possible to leave a wire and then backload this wire onto a duodenoscope.

View of the ampulla in a patient with altered anatomy with a duodenoscope or forward viewing scope. In patients with altered anatomy, the ampulla can be reached with a duodenoscope or a forward viewing endoscope. The duodenoscope is side viewing and allows good visualization of the ampulla (A). The ampulla can be slightly more difficult to visualize with a forward viewing endoscope (B).

8.5

Choledochoduodenal anastomosis

For patients with a choledochoduodenal anastomosis ( Fig. 15A ), a forward-viewing endoscope is sometimes required. The anastomosis is usually located on the anterior side of the bulb. If the anastomosis is patent, the endoscope can be introduced into the bile duct. If it is an end-to-side choledochoduodenal anastomosis ( Fig. 15B ), i.e. if the segment underlying the anastomosis is closed, access to the papilla should be gained using a duodenoscope.

Clinical Tip

Sump syndrome

‘Sump syndrome’ is a rare complication of a side-to-side choledochoduodenostomy ( Fig. 15A ). The common bile duct between the anastomosis and the ampulla of Vater acts as a reservoir in which debris and stones collect. This can result in abdominal pain, cholangitis, biliary obstruction or pancreatitis. ERCP findings include dilated bile or pancreatic duct, and signs of chronic pancreatitis.

Choledochoduodenal anastomosis. (A) A side-to-side choledochoduodenal anastomosis. (B) An end-to-side choledochoduodenal anastomosis.

8.6

Pancreaticoduodenectomy (Whipple’s)

The classic pancreaticoduodenectomy described by Whipple consists of removal of the pancreatic head, duodenum, first 15 cm of the jejunum, common bile duct, and gallbladder, as well as a partial gastrectomy ( Fig. 16 ). There is a side-to-side gastrojejunostomy, often with a long afferent loop and a variety of placements for the pancreatico- and hepatico-jejunostomies. In a pylorus preserving pancreaticoduodenectomy, the gastric antrum, pylorus, and proximal 3–6 cm of the duodenum are preserved, with an end-to-side pylorojejunostomy. The pancreaticojejunostomy is usually located at the apex of the loop, with the hepatic-jejunotomy about half way down the afferent loop. In these patients, pancreatic and biliary anastomoses can rarely be reached with a duodenoscope and a forward viewing endoscope should be used.

Box 3

The afferent loop

How to identify and enter the afferent loop

• •
  

  The afferent loop is almost always more difficult to access than the efferent loop.

  
  
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  The afferent loop is usually adjacent to the lesser curve.

  
  
• •
  

  If it is not possible to intubate the afferent loop, place the patient to prone or supine position.

  
  
• •
  

  A wire can be advanced into the correct loop, and the endoscope guided over the wire into the loop.

  
  
• •
  

  If this fails, a CRE wire-guided balloon is sometimes useful. It can be inflated in the loop, and the endoscope then guided into the loop. These procedures should be performed under fluoroscopic guidance to avoid complications.

How do I know if I am in the afferent loop?

There are several tools you can use to determine if the endoscope is in the correct limb:

• •
  

  Use fluoroscope to confirm that the endoscope is moving towards the right hypochondrium.

  
  
• •
  

  The presence of bile.

Classic Whipple. This is a non-pylorus preserving pancreaticoduodenectomy. The head of the pancreas has been resected. There is a gastrojejunostomy, with an afferent and efferent limb. The afferent limb leads to the hepatico- and pancreaticojejunostomies. Note that the pancreaticojejunostomy is past the hepaticojejunostomy and is often found almost at the end of the afferent limb.

8.7

Gastrojejunal anastomosis (Billroth II)

A Billroth II was often performed in patients with peptic ulcer disease or gastric antral carcinoma and consists of a partial gastrectomy with end-to-side gastrojejunostomy ( Fig. 17 ). The operation may also be known as a Polya and Hoffmeister, depending on how the gastrojejunostomy is performed. A duodenoscope should be used initially. If this is unsuccessful, it can be exchanged for a forward viewing endoscope. There is a native papilla, but the pancreatico-biliary anatomy is reversed as described in the pancreaticoduodenectomy.

Box 4

Jejunojejunal anastomoses

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  Enteric anastomoses can either be in the ‘Y’ configuration, which presents the endoscopist with two lumens to choose from, or in a side-to-side anastomosis, which appears as three lumens.

  
  
• •
  

  The afferent loop is usually the most difficult loop to enter.

Gastrojejunal anastomosis. (A) Demonstrates the relationship of the afferent and efferent limbs in a gastrojejunal anastomosis (Finisterer type procedure). (B) Note the location of the afferent loop – it is at the top left under the fold and is the more difficult limb to enter.

8.10

Cannulating the bile duct and pancreatic duct in patients with Billroth II or Whipple’s procedure

In Billroth II the ampulla will be intact, while in a Whipple’s or other reconstructive surgery there will be a surgical anastomosis (i.e. choledochoenteric anastomosis), and the pancreatic and bile duct anastomoses are usually found separately in the jejunum. The pancreatic duct is often located just proximal to the end of the loop, while the biliary orifice is located proximal to the pancreatic orifice, on the anti-mesenteric wall. As the papilla has been reached retrograde through the afferent loop, the anatomy is reversed by 180° with the biliary orifice found between 5 and 6 o’clock rather than the normal 11 o’clock position ( Fig. 18 ). A straight catheter can be used to cannulate the bile duct or pancreatic duct. It is helpful to maintain an en-face position and exaggerated distance away from the ampulla. A standard cannula is sometimes useful, as a standard sphincterotome may make biliary cannulation difficult in this situation due to its pre-curve. In our experience, guidewire cannulation is particularly useful in these circumstances.

Cannulating the papilla in a patient with a Billroth II. As the papilla has been reached retrograde through the afferent loop, the anatomy is reversed by 180° with the biliary orifice found between 5 and 6 o’clock rather than the normal 11 o’clock position.

8.11

Rendezvous procedure

A percutaneous transhepatic catheter (PTC) is inserted by an interventional radiologist prior to or at the same time as the ERCP.

Technique

• •
  

  Identify the percutaneous catheter ( Fig. 19 )

  
  

  
  

  
  

  

  
  

  
  

  Rendezvous procedure. (A) A PTC catheter is inserted by an interventional radiologist. (B) The catheter is identified. (C) The sphincterotome is advanced in the catheter. Once percutaneous catheter containing the sphincterotome is retracted into the bile duct, the PTC catheter is withdrawn. (D) Biliary sphincterotomy is performed.

  
  
  
  
• •
  

  Insert a sphincterotome into the catheter

  
  
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  The percutaneous catheter containing the sphincterotome is retracted into the bile duct

  
  
• •
  

  The sphincterotome is placed in the papilla and a standard sphincterotomy performed.

Alternative techniques

• •
  

  Use the PTC catheter as a guide, and cannulate alongside the catheter using a sphincterotome with a wire.

  
  
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  A guidewire is inserted percutaneously ( Fig. 20 ). The guidewire is retrieved using a snare and gently pulled into the instrument channel. A sphincterotome is then inserted over the guidewire and a standard sphincterotomy is performed.

  
  

  
  

  
  

  

  
  

  
  

  Rendezvous procedure. (A) Percutaneous insertion of a guidewire through the papilla. (B) Retrieval of the guidewire using a snare which is re-inserted in the operating channel. (C) A sphincterotome is inserted over the guidewire. (D) Biliary sphincterotomy is performed.

  
  
  
  
• •
  

  A variation of this is where a catheter has been placed by radiology. Insert a guidewire through the catheter ( Fig. 21 ). The percutaneous guidewire is retrieved using a snare and pulled out of the instrument channel. The guide catheter is mounted on the guide wire in the bile duct. The stent is pushed through the stenosis.

  
  

  
  

  
  

  

  
  

  
  

  Alternative rendezvous technique for access to the papilla. (A) The percutaneous guidewire is recovered using a diathermy loop. (B) The guide catheter is mounted on the guidewire in the bile duct. (C) The stent is pushed through the stenosis. (D) Withdrawal of the guidewire before withdrawal of the catheters. (E) Stent in the hepatic parenchyma to be repositioned.

  
  

Warning!!

It is very important to work closely with radiology. Large catheters should not be removed without prior discussion with radiology, as these can cause bile to leak into the peritoneum.

Clinical tips for patients with a PTC

• •
  

  If the sphincterotome is being advanced over the wire, a long wire (>450 cm) is required as it will need to pass from the liver, through the duodenoscope.

  
  
• •
  

  Always manipulate the catheter/wire gently as liver laceration can occur.

  
  
• •
  

  Some of the PTC catheters have a fixed pigtail to maintain their position in the duodenum. This must be either released or cut prior to removing the catheter or liver laceration can occur.

  
  
• •
  

  It is advisable to insert a regular guidewire through the PTC catheter prior to manipulating it to minimize the risk of laceration.

PTC, percutaneous transhepatic cholangiogram.

9

Successful cannulation rate

Cannulation of the papilla is successful in 95–98% of cases when performed by an experienced endoscopist. The pancreatic ducts are opacified on average in 90–95% of cases and the bile ducts in 85–90%. Failures are due to duodenal stenosis, a papillary lesion, or the intradiverticular location of the papilla.

In patients with altered anatomy, success rates depend on the type of surgery. Patients with a pyloroplasty, Billroth I, or choledochoduodenal anastomosis, have a similar success rate to normal ERCP. Patients with a Roux-en-Y have lower success rates of between 60% and 75%, provided the afferent loop is not too long or located transmesocolically.

10

ERCP in children

ERCP in children should be undertaken under general anesthesia. A diagnostic side-viewing duodenoscope may be used from the age of 1 year upwards. A therapeutic duodenoscope can be used in children over 5 foot. A 7.5 mm diameter duodenoscope with a 2.0 mm operating channel is available for use in children under the age of 1. There are few indications: bile duct stones, jaundice due to bile duct malformation, recurrent pancreatitis, pancreatic trauma, bile stones.

1

Cytology

The cytological study of the bile or pancreatic juice can help to diagnose cancer of the bile ducts or pancreas and has a sensitivity of between 35% and 70%, with a specificity of >90%. Fluid can be collected by selective catheterization, or by collection of duodenal aspiration either after irrigation with saline or following stimulation with either CCK or secretin. Stents inserted into potentially neoplastic stricture should also be sent for cytological analysis.

2

Biopsies

Endoscopic transpapillary biopsies of a localized lesion or stenosis of the biliary or pancreatic ducts are more difficult, with a sensitivity of between 43% and 88% and a specificity of >90%. It is particularly difficult to introduce biopsy forceps through an intact papilla and to position them correctly within the lesion. Biopsies of the major papilla should be taken in patients who are suspected of having autoimmune pancreatitis.

3

Brushing

The sensitivity of endoscopic transpapillary brush cytology is dependent on the type of tumor, as well as the number of passes made with the brush. Thus, it is important to brush multiple times, and to repeat brushing if the patient returns for repeat ERCP. Tumors which compress the bile duct (i.e. pancreatic) have a lower sensitivity than primary biliary cancer. If a pancreatic neoplasm is suspected, endoscopic ultrasound should be considered as the initial procedure of choice to obtain tissue.

A new technique, inserting a guidewire through a stricture and collecting juice above the stricture, has a high sensitivity (93%) and specificity (100%) in a single study. Further studies are required to confirm these promising results.

4

Biochemical examination of bile and pancreatic juice

1

Normal and variant biliary anatomy

The Couinaud classification gives eight functionally independent segments, numbered I through VIII ( Fig. 1 ). The segments are numbered in a clockwise manner starting with the caudate lobe (segment I). Each segment has its own vascular inflow, outflow, and biliary drainage. In the center of each segment there is a branch of the portal vein, hepatic artery, and bile duct. In the periphery of each segment, there is vascular outflow through the hepatic veins. The liver is divided by vascular structures. The right hepatic vein divides the right lobe into anterior and posterior segments. The middle hepatic vein divides the liver into right and left lobes, while the left hepatic vein divides the left lobe into medial and lateral parts. The portal vein divides the liver into upper and lower segments.

Normal segmental anatomy of the liver. This drawing shows normal biliary segmental anatomy, which is observed in 56% of individuals.

The biliary drainage runs in parallel to the portal venous supply. The right hepatic duct drains the segments of the right liver (V–VIII), with the right posterior duct draining the posterior segment (VI and VII), and the right anterior duct draining the anterior segments (V, VIII). The right posterior duct has an almost horizontal course, while the right anterior duct tends to have a more vertical course. The left hepatic duct is formed from tributaries draining segments II–IV. The common hepatic duct is formed by fusion of the right and left hepatic ducts. The duct draining the caudate lobe (I) usually joins the origin of the right or left hepatic duct. The cyst duct usually joins the common hepatic duct below the confluence of the right and left hepatic ducts ( Fig. 2 ).

Extrahepatic biliary tree.

There are variations of this classic anatomy. The most common variant, which is present in up to 19% of the population, is where the right posterior duct drains into the left hepatic duct before its confluence with the right anterior duct ( Fig. 3D ). Another common variant, occurring in 12% of individuals, is where the right posterior duct empties into the right aspect of the right anterior duct. Another common variant is where the right anterior, posterior, and left hepatic ducts drain simultaneously into the common hepatic duct ( Fig. 3A ). In these individuals, the right hepatic duct is virtually non-existent.

Note

ERCP images can only be interpreted with the patient in dorsal decubitus position.

Hepatic duct variation. Variant anatomy most commonly affects the right hepatic duct. (A) The right posterior (RP), right anterior (RA) and left hepatic duct (LHD) insert together. This occurs in 12% of individuals. (B) Segments II, III and IV join the right anterior and posterior ducts in 3% of people. (C) This is the most common anatomical variation, occurring in 16% of individuals, where the right anterior hepatic duct (RA) drains into the left hepatic duct (LHD), prior to its confluence with the right posterior hepatic duct (RP). Other variations include insertion of the left hepatic duct into the right posterior hepatic duct, prior to insertion of the right anterior hepatic duct (4%) (D); insertion of the right anterior hepatic duct into the left hepatic duct followed by a confluence with the right posterior hepatic duct (5%) (E); insertion of the right posterior hepatic duct into the left hepatic duct which then joins the right anterior hepatic duct (1%) (F); and (G) confluence of the left hepatic duct with the right posterior hepatic duct which then join the right anterior hepatic duct (1–2%).

The cystic duct termination exhibits a number of variants. A common variation is where there is a low insertion of the cystic duct into the distal third of the common bile duct (9%) ( Fig. 4 ). Another variation is where the cystic duct drains into the left side of the common hepatic duct.

Variations in cystic ductal anatomy. The cystic duct termination exhibits a number of variants. A common variation is where there is a low insertion of the cystic duct into the distal third of the common bile duct (9%) (C). Another variation is where the cystic duct drains into the left side of the common hepatic duct (D).

The common bile duct terminates at the ampulla of Vater, where it joins the main pancreatic duct (Wirsung’s duct) ( Fig. 5 ). There are a number of variations in the communication between the common bile duct and Wirsung’s duct. It is important to be familiar with these variations when cannulating the papilla ( Fig. 6 ). In the majority of cases (98%), the papilla has a single orifice (type I). The biliary duct and the pancreatic duct may have separate openings in the papilla (type II) ( Fig. 7 ) or openings at different points in the duodenum (type III). There are two types of common opening (or common channel):

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  Type 1a corresponds to a long common channel with extraduodenal confluence of the two channels ( Fig. 8 ).

  
  

  
  

  
  

  

  
  

  
  

  Type 1a common channel. These images illustrate a type 1a, with a long common channel (arrow).

  
  
  
  
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  Type 1b corresponds to a common channel confined to the mucosa and to the duodenal submucosa.

Ampulla of Vater with junction of the common bile duct and Wirsung’s duct. (1) Common sphincter. (2) Choledochic sphincter. (3) Wirsung’s duct sphincter.

Variations in the communication between the common bile duct and Wirsung’s duct. Type 1a has a long common bile duct (>1 cm) with one orifice. Type 1b has a short common bile duct with one orifice. Type 2 has a separate orifice for the bile and pancreatic ducts. Type 3 has separate orifices for the bile and pancreatic ducts at different points in the duodenum.

Type II opening with separate pancreatic (black arrow) and bile ducts.

When the common channel is >15 mm long, the frequency of congenital anomalies of the bile ducts (choledochal cyst, Caroli disease) and cholangiocarcinoma is believed to be higher.

The arterial supply of the papilla exhibits numerous anatomical variations, which are determined by the retroduodenal artery and the branch of the upper pancreaticoduodenal artery. Significant bleeding can occur depending on the configuration of the blood vessels at the papilla ( Fig. 9 ).

Arterial supply of the papilla. (A) This configuration is associated with a low hemorrhagic risk with sphincterotomy. (B) This configuration is associated with increased risk of bleeding due to a low arterial trunk which can be cut during sphincterotomy.

1.1

Normal pancreas and its variants

The main pancreatic duct rises steeply in the head, then crosses the upper abdomen horizontally or in a slightly ascending manner ( Fig. 10 ). In healthy individuals, the shape of the pancreatic duct is variable, and diagnostic conclusions cannot be based on shape alone. Loops (ansa loops) may be observed, particularly in the isthmus ( Fig. 11 ). The diameter of the pancreatic duct is on average 4 mm in the head of the pancreas, 3 mm in the body and 2 mm in the tail. The duct of Santorini usually connects the pancreatic duct to the accessory papilla. Collateral branches open perpendicular to the axis of the pancreatic duct. Their normal diameter should not exceed 1 mm. The diameter of the pancreatic duct increases with age. The aging of the pancreas is accompanied by irregularities in ductal diameter and may make differential diagnosis with incipient chronic calcifying pancreatitis difficult.

Normal pancreatic ductal anatomy. (1) Duct of Wirsung or pancreatic duct. (2) Duct of Santorini. (3) Secondary ducts. (4) Parenchyma.

Ansa pancreatica loop. A wire is in the pancreatic duct. Note where the tip of the sphincterotome is (arrow) there is an alfa loop consistent with ansa pancreatica but the wire is in the direction of the common bile duct. Ensure careful injection.

1.2

Congenital anomalies of the pancreatic ducts

Annular pancreas is characterized by a ring of pancreatic tissue surrounding the descending portion of the duodenum. It is thought to be due to incomplete rotation of the pancreatic ventral bud. It is a rare anomaly in adults (0.1% of ERCP).

Pancreas divisum ( Fig. 12 ) is the embryonic anomaly most commonly found in adults (5% of ERCP), characterized by the failure of the ventral and dorsal pancreatic ducts to fuse. A definite diagnosis can be obtained only by cannulation of the major papilla and the accessory (minor) papilla.

Normal pancreatogram and pancreas divisum. (A) Normal pancreatogram. (B) Ventral duct (pancreas divisum). (C) Dorsal duct (pancreas divisum).

Cannulation of the major papilla opacifies the ventral pancreas ( Fig. 12B ). The ventral duct is short with a small diameter. The length varies from a few millimetres to 5 or 7 cm. If the duct is very short, injection of contrast medium results very quickly in acinarization, which must not be confused with a submucosal injection. If the duct measures 3 or 4 cm, complete occlusion of the head of the pancreas by cancer must be excluded. Opacification of the dorsal pancreas ( Fig. 12C ) should be performed to confirm the diagnosis of pancreas divisum if the ventral pancreas is completely atrophic and invisible after catheterization of the major papilla. Opacification also allows visualization of lesions in the dorsal pancreas. Incomplete forms of pancreas divisum exist ( Fig. 13 ).

Variations in pancreatic anatomy.

2

Post-surgical anatomy

It is important to understand post surgical anatomy (see also Ch. 10.6 ), as it is encountered frequently due to the increase in obesity and gastric bypass surgery. Gastroduodenal anastomoses ( Fig. 14 ) and certain types of choledochoduodenal anastomoses ( Fig. 15 ) can usually be reached with a duodenoscope. The papilla is more difficult to reach in patients with Roux-en-Y anatomy ( Fig. 16 ). A pediatric colonoscope, enteroscope or double/single balloon or spiral enteroscopy may be required to reach the papilla. The main problem in these patients is the length of small bowel that has to be traversed. The shortest distance is encountered with a Billroth II ( Fig. 17 ), with the longest distance typically associated with Roux-en-Y, associated with gastric bypass. Whether the limb has been placed antero- or retrocolic can also affect the ability to reach the papilla ( Fig. 18 ). Retrocolic is associated with acute turns which can be difficult to negotiate but it’s a short way to find papilla. Anterocolic is a long way to reach papilla.

Gastroduodenal anastomoses. (A,B) represent two different types of gastroduodenal anastomoses. A Pean (A) anastomosis is commonly found in Europe, while a Billroth I is seen more frequently in the USA (B). These types of surgery were often performed for treatment of peptic ulcer disease and are seen less frequently now due to eradication of H. pylori and use of proton pump inhibitors.

Choledochoduodenal anastomoses. (A) Side-to-side choledochoduodenal anastomosis. (B) End to side choledochoduodenal anastomosis. (C) Choledochojejeunal anastomosis with Roux-en-Y anastomosis.

Roux-en-Y. This is the classic Roux-en-Y configuration found in patients with Billroth II, Finsterer and Polya anatomy. Note that the Roux limb can be either antero- or retrocolic (as found in this figure). Retrocolic Roux limbs have greater angulation and can be more difficult to traverse.

Gastrojejunal anastomoses. These figures represent different types of gastrojejunal anastomoses. (A) Polya is found more commonly in Europe, while a Billroth II (B) is performed commonly in the UK and USA for patients with pancreatic cancer in the head. (C,D) represent a classic and an isoperistaltic Finsterer gastrojejunostomy. Note that the Roux limbs are labelled A and E. A represents the afferent limb, which contains the papilla or choledochoenterostomy. E is the efferent limb which leads to the remaining small bowel. It is very important to check what limb you are in. This is usually done by looking for bile (afferent limb) and by using fluoroscopy to check your position. The endoscope should be going in the direction of the right upper quadrant. If you are not, you may be in the efferent limb.

Roux limbs. In (A) the Roux limbs have been arranged in a classic omega pattern with a side-to-side anastomosis. The omega loop and retrocolic position make it difficult to reach the papilla. The configuration in (B) is better, as there is a relatively straight path to the papilla. (C) Demonstrates enterocolic Roux limb. Patients with this type of anatomy have less angulation of the bowel, compared with retro-colic Roux-limbs; however, the distance to the papilla is greater, which can make accessing the papilla challenging.

Introduction

It is very important that high quality radiographic images are obtained. The type of contrast used, the amount injected, and how to obtain good radiographic views are discussed below.

1

Dilute or full strength contrast media?

Contrast media can be used undiluted (300 mg iodine/mL), or diluted to 50%. In most cases, undiluted contrast is usually used. This provides excellent visualization of neoplastic stenoses or diseases of the small bile or pancreatic ducts. Diluted contrast is often used where biliary or pancreatic stones are suspected, as stones are often not seen if full strength contrast is used.

2

How much contrast should be injected?

Continue injecting until the intrahepatic bile ducts or the small pancreatic ducts are visible. Do not overfill the gallbladder (due to the risk of cholecystitis) or secondary pancreatic ducts (due to the risk of pancreatitis). Usually 3–5 mL of contrast medium is sufficient to opacify the pancreatic ducts, while 15–20 mL is required for the bile ducts. In patients who have a sphincterotomy, a balloon catheter may be required to allow adequate opacification of the ducts.

3

When and how many X-ray images should be taken?

X-rays should be taken at different stages. An image should be taken before injection and passing the endoscope, as well as in different stages of opacification (as you start injecting, once injection is completed and while contrast is emptying from the ducts). Images taken from different views (left lateral decubitus, dorsal decubitus with slight rotation to the right) can be used to clearly define abnormal areas, and to identify normal structures such as the cystic duct take off. An image of contrast emptying from the bile duct is taken after the duodenoscope has been removed. An image is often taken in the supine position after removing the duodenoscope to exclude perforation for medicolegal reasons. The pancreatic duct, however, empties quickly and images must be taken during the injection of the contrast medium.

4

Diagnostic problems and interpretation errors

Interpreting cholangiographic and pancreatographic images sometimes raises difficult problems, which should be borne in mind.

4.1

Stones or bubbles?

A filling defect corresponds in the majority of cases to a stone; however, occasionally it may be due to parasites (gallbladder with hydatid cyst, Ascaris , flukes), benign or malignant tumor fragments, hemobilia, or even air bubbles. To differentiate air bubbles from stones, tilt the table in such a way that the patient’s head is elevated (reverse Trendelenburg position). This will cause air bubbles to rise and stones to fall ( Fig. 1 ).

Diagnostic dilemmas and interpretation errors. (A,B) Differentiation of a stone versus an air bubble. (A) A possible stone is present in the common bile duct. A stone generally rises towards the intrahepatic bile ducts with a patient prone. (B) Air bubbles do not usually rise. (C) Adenoma arising in the common bile duct appears as a fixed, non-moving object. (D) Hemobilia. (E,F) False underfilling: stone occluding the lower common bile duct (complete filling necessary before drawing conclusions).

Errors of interpretation can be reduced by some simple principles:

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  Use contrast medium diluted to 75% if stones are suspected.

  
  
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  Use undiluted contrast medium if a tumor is suspected (dense bile due to stasis prevents accurate assessment of the limit of the tumor).

  
  
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  Catheterization of the bile and pancreatic ducts must be selective and deep to achieve correct opacification which is the key to the correct interpretation of the images.

  
  
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  In the left lateral decubitus and ventral position, air bubbles remain in the lower common bile duct, while stones rise to the hilum. In the dorsal decubitus position, the opposite occurs.

  
  
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  A close examination of all the images, including those taken in the dorsal decubitus position, is essential. This allows the following to be confirmed:

  
  
  
  
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    Correct drainage of the bile and pancreatic ducts

    
    
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    Opacification of the left intrahepatic bile ducts

    
    
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    A stone pushed by the injection into the intrahepatic bile ducts which has re-descended with the patient in dorsal decubitus.

  
  
  
  
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  The catheter can be connected to a pump which injects contrast. This should be purged correctly with a constant drop-wise injection system to reduce the risk of injecting bubbles. A stone located in the papilla or in the bile duct may simulate the image of a tumor, by its immobility.

  
  
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  A stone located in the papilla may not be identified and present a misleading tapered aspect. Images taken during emptying show the normal lower common bile duct with a tapered appearance varying over time, related to the alternate contraction and relaxation of the sphincter of Oddi. A stone or a tumor yields a fixed image.

  
  
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  A normal dilated bile duct, without visible stones, does not automatically rule out the possibility of stones. Microlithiasis may be present, the stone may be hidden in contrast medium, or the stone may have migrated since the clinical event.

  
  
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  An image in which contrast does not appear to fill beyond the bile duct may correspond to obstruction by a tumor or a false image due to incomplete opacification. This is also true for the left intrahepatic bile ducts, which fill only in excess pressure or in images taken with the patient in dorsal decubitus.

  
  
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  The benign or malignant nature of a biliary stenosis is sometimes difficult to determine from the radiological appearance alone.

  
  
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  Obstruction of the intrapancreatic bile duct may correspond to cancer of the pancreas or of the common bile duct.

  
  
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  Dilation of the bile duct does not always correspond to sphincter of Oddi stenosis, particularly in elderly or cholecystectomized individuals.

  
  
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  Cancer in the region of the ampulla of Vater infiltrating the ampulla is not endoscopically visible and may appear as irregular stricture of the lower common bile duct during opacification.

  
  
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  Minor anomalies during pancreatography are difficult to interpret. They may correspond to incipient chronic pancreatitis or to a normal pancreas, particularly in the elderly.

  
  
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  Compression of bile duct by the gallbladder may be secondary to cholecystitis, a stone impacted in the cystic duct or a tumor lesion (gallbladder cancer).

  
  
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  Incomplete stenosis of the pancreatic duct may correspond to cancer or to pancreatitis.

  
  
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  Complete stenosis of the pancreatic duct may be due to cancer, pancreatitis or to a technical fault (injection of air bubbles or incomplete opacification which must not be confused with pancreas divisum).

  
  
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  Normal pancreatography does not rule out incipient chronic pancreatitis or cancer of the peripheral pancreas.

  
  
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  Incorrectly filled intrahepatic bile ducts should be distinguished from sclerosing cholangitis.

Most of these diagnostic problems can be resolved by correct catheterization technique, rigorous analysis of the radiological images and precise knowledge of the limits of ERCP.