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DOI: 10.1148/rg.266055730
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RadioGraphics 2006;26:1603-1620
© RSNA, 2006

EDUCATION EXHIBIT

Normal and Pathologic Features of the Postoperative Biliary Tract at 3D MR Cholangiopancreatography and MR Imaging1

Christine Hoeffel, MD, Louisa Azizi, MD, Maité Lewin, MD, PhD, Valérie Laurent, MD, Christophe Aubé, MD, Lionel Arrivé, MD and Jean-Michel Tubiana, MD

1 From the Department of Radiology, Hôpital Saint-Antoine, 184 rue du Faubourg Saint-Antoine, 75571 Paris Cedex 12, France (C.H., L.A., M.L., L.A., J.M.T.), and Université Paris–Descartes, Faculté de médecine Cochin–Port-Royal, Paris, France (C.H.); Department of Radiology, CHU Nancy-Brabois, Vandoeuvre-lès-Nancy, France (V.L.); and Department of Radiology, CHU Angers, Angers, France (C.A.). Presented as an education exhibit at the 2005 RSNA Annual Meeting. Received October 28, 2005; revision requested February 24, 2006; revision received and accepted April 17. All authors have no financial relationships to disclose. Address correspondence to C.H. (e-mail: christine.hoeffel{at}sat.ap-hop-paris.fr).


   Abstract
Top
 Abstract
LEARNING OBJECTIVES FOR TEST...
 Introduction
 MR Cholangiographic Technique
 Normal Postoperative Findings
 Complications after Surgery
 Conclusions
 References
 
Magnetic resonance (MR) imaging with cholangiopancreatographic sequences plays a critical role in evaluating alterations in the biliary tract after surgical procedures such as cholecystectomy, liver transplantation, hepatic resection, and the creation of a biliary-enteric anastomosis. MR cholangiopancreatography, a rapid, noninvasive, and accurate imaging technique for the assessment of early and late complications of hepatobiliary surgery, usually enables the identification of normal and abnormal postoperative changes. In cases of complete obstruction of the bile duct, MR cholangiopancreatography allows analysis of the biliary tract above and below the level of the obstruction, a capability essential for treatment planning and one that is not provided by either endoscopic retrograde cholangiopancreatography or percutaneous transhepatic cholangiography. MR cholangiopancreatography is particularly useful for the evaluation of biliary-enteric anastomoses, for which an endoscopic approach is generally precluded. It also can help detect and localize bile duct strictures and stones and can help accurately classify bile duct injuries. It is useful for detecting bile leaks, although it generally does not directly depict the extravasation of bile. In addition to MR cholangiopancreatography, T1- and T2-weighted MR imaging may be performed to depict extrabiliary soft-tissue structures and abnormalities such as an abscess, tumor recurrence or metastasis, hematoma, or hemobilia. Mangafodipir trisodium–enhanced MR cholangiopancreatography, a recently developed technique that provides a combination of anatomic and functional information, is particularly helpful for documenting bile leaks because it allows a functional evaluation of biliary excretion and may directly depict bile leakage from injured ducts.

© RSNA, 2006


   LEARNING OBJECTIVES FOR TEST 1
Top
 Abstract
 LEARNING OBJECTIVES FOR TEST...
Introduction
 MR Cholangiographic Technique
 Normal Postoperative Findings
 Complications after Surgery
 Conclusions
 References
 
After reading this article and taking the test, the reader will be able to:


   Introduction
Top
 Abstract
 LEARNING OBJECTIVES FOR TEST...
 Introduction
MR Cholangiographic Technique
 Normal Postoperative Findings
 Complications after Surgery
 Conclusions
 References
 
During the past decade, the increasing number of hepatobiliary surgical procedures, mainly laparoscopic cholecystectomies but also liver transplantations, has been associated with an increase in postoperative biliary complications. Biliary complications are a major cause of morbidity and mortality, and accurate diagnosis is crucial for treatment planning. Bile duct injuries account for the highest number of complications of hepatobiliary surgeries overall (1). Early complications include bile duct injury caused by a mistakenly placed surgical clip, erroneous cutting of a bile duct because of misinterpretation of the biliary anatomy, periductal bile leakage with resultant edema, fibrosis or secondary stricture, and ischemia. Bile duct strictures are the most common late complications and may develop a few months or many years after surgery (2).

Either percutaneous transhepatic cholangiography or endoscopic retrograde cholangiopancreatography (ERCP) traditionally has been performed in patients in whom iatrogenic bile duct injury is suspected; however, both techniques are invasive and may lead to serious complications. In cases of complete ductal obstruction, percutaneous transhepatic cholangiography cannot depict the area below the obstruction, and ERCP cannot provide a clear view of the biliary tree above the site of obstruction. Moreover, in patients with a biliary-enteric anastomosis, in whom endoscopic access is rarely possible, percutaneous transhepatic cholangiography may be associated with an increased risk of complications. An alternative technique for the evaluation of the biliary tract in such patients is computed tomographic (CT) cholangiopancreatography. However, at CT cholangiopancreatography performed with an oral or intravenous contrast agent, the biliary excretion of contrast material cannot be guaranteed in the presence of a high-grade bile duct obstruction, whereas CT cholangiopancreatography performed without a biliary contrast agent does not enable a detailed three-dimensional (3D) evaluation of the biliary tree. Current multi–detector row CT scanners may help overcome these limitations of CT cholangiopancreatography (3).

Although patients frequently undergo cross-sectional imaging with CT or ultrasonography, magnetic resonance (MR) cholangiopancreatography has become the imaging modality of choice at many institutions for the work-up of patients with suspected bile duct abnormalities. The examination is short and can be performed emergently in patients for whom the success of treatment depends on quick decision making. In patients who have undergone surgery and in whom bile duct complications are suspected, MR cholangiopancreatography is an accurate imaging technique for assessing the integrity of the surgical procedure and investigating possible causes of postoperative symptoms. This article reviews the normal postoperative changes of the biliary tract after hepatobiliary surgery, as well as the appearance of early and late complications (eg, retained calculi, bile duct injuries, leaks, anastomotic or nonanastomotic strictures, obstructions due to hemobilia, ascending cholangitis and abscesses, stones, recurrent tumors and metastases, and cystic duct remnant mucoceles) at 3D volumetric MR cholangiopancreatography and at MR imaging.


   MR Cholangiographic Technique
Top
 Abstract
 LEARNING OBJECTIVES FOR TEST...
 Introduction
 MR Cholangiographic Technique
Normal Postoperative Findings
 Complications after Surgery
 Conclusions
 References
 
At our institutions, MR cholangiopancreatography is performed on a 1.5-T unit (Magnetom Symphomy; Siemens, Erlangen, Germany) by using a six-channel phased-array body coil. Patients are placed in a supine head-first position. We use sequences that are heavily T2 weighted to depict the fluid-containing biliary tree and pancreatic duct. Our protocol includes an axial free-breathing half-Fourier acquisition single-shot turbo spin-echo (HASTE) sequence without fat suppression (repetition time msec/echo time msec, 1200/114; matrix, 176 x 256; flip angle, 180°; section thickness, 6 mm; acquisition time, 80 sec) and a free-breathing 3D high-spatial-resolution fast spin-echo (SE) sequence with an extremely long echo time (1400/800; flip angle, 180°). A –90° radiofrequency pulse (the restore pulse) is applied at the end of the echo train to flip the transverse magnetization to the longitudinal direction, shorten the spin relaxation time, and accelerate the relaxation of the longitudinal magnetization while maintaining the same contrast resolution and reducing the acquisition time. The matrix is symmetric (256 x 256), the section thickness is 1 mm, and the voxel size is 1 x 1 x 1 mm. A stack of sections is acquired for diagnostic purposes. Postprocessing of the image data is performed to obtain maximum intensity projection (MIP) images and multiplanar reformatted images. The increased spatial resolution of the sequence is reflected by the symmetric matrix and the isotropic voxel. With the use of a parallel acquisition technique with an acceleration factor of two, the acquisition time can be further reduced, which in turn makes it possible to obtain a higher spatial resolution with a stable signal-to-noise ratio. The typical acquisition time is 3–6 minutes for respiratory-triggered navigator-gated acquisitions with the prospective acquisition and correction, or PACE, technique; however, the acquisition time partly depends on the patient’s respiratory pattern (the length of each respiratory cycle). The 3D imaging technique has potential advantages over two-dimensional imaging, including the capacity to obtain thinner sections with no gap and a higher signal-to-noise ratio. Because partial volume averaging effects may obscure small stones and subtle mural irregularities, thin-section source images must always be reviewed. Before the restore pulse sequence was available, we used a breath-hold single-shot rapid acquisition with relaxation enhancement (RARE) sequence (2800/1100; matrix, 230 x 384; field of view, 400 mm; flip angle, 150°; slab thickness, 10–20 mm; acquisition time, 3 sec), and we still use the latter sequence when the patient’s respiratory pattern is too irregular.

When a bile leak is suspected, we sometimes use mangafodipir trisodium (Teslascan; Nycomed Amersham Imaging, Oslo, Norway), a hepatobiliary MR imaging contrast agent that consists of manganese bound to a vitamin B6 analog. The contrast agent is administered intravenously, taken up by the liver, and transported to bile, where it causes T1 shortening as a result of the paramagnetic effects of the manganese ion. Because the contrast agent is excreted primarily via the biliary system, it is suitable for use in the MR imaging assessment of hepatobiliary functioning. Manganese also produces T2 shortening. The contrast-enhanced liver and functioning bile ducts, therefore, have higher signal intensity on T1-weighted images and lower signal intensity on T2-weighted images. The high signal intensity of the biliary system during excretion of the contrast agent produces excellent contrast with the liver parenchyma and hepatic vessels in the background. The signal intensity of the liver begins to increase within 1–3 minutes after intravenous injection of the contrast agent, and steady-state enhancement of the liver is achieved in approximately 5–10 minutes. Biliary excretion of the contrast agent is usually apparent in a nondilated biliary system within 10 minutes after injection (4,5). The contrast agent is injected slowly (0.1 mL/kg), and a T1-weighted fat-saturated volumetric interpolated breath-hold examination (4.3/2, 3; flip angle, 15°; matrix, 145 x 384; field of view, 430 mm; 44 partitions with an interpolated section thickness of 1.3 mm) is performed in the axial and oblique coronal planes before and 40 minutes after administration of the contrast agent. The imaging study is terminated when the contrast material is seen entering the duodenum or extravasating with bile from a biliary duct. Source images from the 3D data set are reviewed, and MIP images are generated with and without a restricted volume.


   Normal Postoperative Findings
Top
 Abstract
 LEARNING OBJECTIVES FOR TEST...
 Introduction
 MR Cholangiographic Technique
 Normal Postoperative Findings
Complications after Surgery
 Conclusions
 References
 
The most frequent interventional procedure that affects the biliary tract is cholecystectomy. Other major interventions in the biliary tract include choledochocholedochostomy after liver transplantation, biliary-enteric anastomosis (hepaticojejunostomy), and ligation of hepatic ducts during partial hepatectomy or segmentectomy. Less common surgical procedures include a choledochoduodenostomy and a biliary-enteric anastomosis to the right or left hepatic ducts or their intrahepatic branches when a hepaticojejunostomy between the common hepatic duct and the jejunum below or at the confluence of the major hepatic ducts is unfeasible.

After cholecystectomy, a variable length of the cystic duct is left in place. The cystic duct remnant usually is 1–2 cm long, but remnants up to 6 cm in length may be seen (6) (Fig 1). A longer remnant may be left after cholecystectomy, in the presence of a long parallel cystic duct or a low and medial-sided insertion of the duct. The diameter of the main bile duct may increase slightly after cholecystectomy, but most patients do not experience significant compensatory dilatation of the main duct. A maximal diameter of 13 mm, with subtle tapering, is within the normal range for the postoperative common bile duct (7).


Figure 1
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  		Figure 1.  Normal biliary ductal anatomy in a 45-year-old man after cholecystectomy. Coronal MIP image from a 3D respiratory-triggered T2-weighted fast SE restore MR imaging data set shows a high insertion of the cystic duct (arrow).

 
Choledochocholedochostomy and hepaticocholedochostomy are performed during hepatic transplantation and surgical treatment of biliary tract injury. In hepatic transplantation, the choledochocholedochostomy is the more common of the two procedures. A biliary tube (T tube or straight biliary tube) is left in place for a variable period of time (6 weeks to 6 months) after transplantation (Fig 2). The T tube is placed through the choledochotomy into the common bile duct of the recipient. When a straight tube is used, placement is via the donor cystic duct remnant, which obviates choledochotomy. A size disjuncture between the donor common bile duct and the recipient common bile duct was found in 18% of patients in one study (8). Generally, the donor’s common bile duct is thin and smooth and the recipient’s is slightly enlarged (Fig 3), but occasionally the donor’s common bile duct may be abnormally large and the recipient’s duct thin and smooth. Although the type of anastomosis may vary, the absence of intrahepatic dilatation and the presence of gradual tapering of the bile duct lumen instead of focal complete obliteration allow differentiation of an anastomosis from stenosis. The gallbladder is removed from both the donor and the recipient prior to transplantation. Two cystic duct remnants (one each in the donor and the recipient) may be seen with a primary duct-to-duct anastomosis. Kinking of the common bile duct at the level of the anastomosis may be observed (Fig 4) (9).


Figure 2
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  		Figure 2.  Normal postoperative appearance after liver transplantation with a duct-to-duct anastomosis. Coronal MIP image from a 3D respiratory-triggered T2-weighted fast SE restore data set shows two cystic duct remnants (straight arrows) and the anastomosis (curved arrow), through which a T tube has been placed.

 

Figure 3
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  		Figure 3.  Size disjuncture between donor and recipient common bile ducts in a 60-year-old man with a liver transplant. Coronal MIP image from a 3D respiratory-triggered T2-weighted fast SE restore data set shows that the recipient common bile duct (curved arrow) has a larger diameter than that of the donor (arrowhead). The liver function is normal, and the intrahepatic ducts are not dilated. Note the two cystic duct remnants (straight arrows).

 

Figure 4
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  		Figure 4.  Normal duct-to-duct anastomosis in a 56-year-old man 5 years after orthotopic liver transplantation. Coronal MIP image from a 3D respiratory-triggered T2-weighted fast SE restore data set shows a tortuous course of both the donor duct and the recipient duct, with kinking at the site of the anastomosis (arrow). Note the long parallel cystic duct remnant (arrowhead).

 
Biliary-enteric anastomoses are performed in a variety of surgical procedures, including the Whipple procedure (choledochojejunostomy [Roux-en-Y anastomosis]); hepatic transplantation in the presence of preexisting biliary tract disease or secondary biliary cirrhosis (choledochojejunostomy or hepaticojejunostomy); surgical repair of a bile duct injury; choledochal cyst resection; hepatectomy; and surgical treatment of primary sclerosing cholangitis, cholangiocarcinoma, and choledocholithiasis. A biliary-enteric anastomosis is usually created between a normal bile duct segment proximal to the site of disease and a segment of the gastrointestinal tract, commonly a Roux-en-Y loop of the jejunum, which is brought up for anastomosis (Figs 5, 6). The blind end of the jejunal loop is of variable length. There is usually no cystic duct remnant, although a very small remnant may be left in place.


Figure 5
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  		Figure 5.  Normal Roux-en-Y anastomosis in a 70-year-old man after a Whipple procedure for pancreatic carcinoma. Coronal reformatted image from a 3D respiratory-triggered T2-weighted fast SE restore data set shows a short segment of the common hepatic duct anastomosed to the jejunal loop (arrows), with no cystic duct remnant. Note the trifurcation of the biliary duct.

 

Figure 6
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  		Figure 6.  Biliary-enteric anastomosis in a 30-year-old man who underwent resection of a choledochal cyst in childhood. Coronal MIP image from a 3D respiratory-triggered T2-weighted fast SE restore data set depicts a normal three-way anastomosis between a jejunal loop (straight arrow) and the left hepatic duct (arrowhead) and right posterior and anterior ducts (curved arrows).

 

   Complications after Surgery
Top
 Abstract
 LEARNING OBJECTIVES FOR TEST...
 Introduction
 MR Cholangiographic Technique
 Normal Postoperative Findings
 Complications after Surgery
Conclusions
 References
 
Complications may occur singly, but complex biliary complications, such as bile duct injury combined with bile duct leakage, are frequently seen.

Calculus Retention
On occasion, calculi may remain within the cystic duct remnant, the intrahepatic ducts, or the extrahepatic biliary tree after a laparoscopic cholecystectomy (Fig 7). Retained common bile duct calculi may even lead to secondary bile leakage due to displacement of the cystic duct clips because of increased biliary pressure (10). Calculi also may remain after a sphincterotomy or biliary-enteric anastomosis for choledocholithiasis. For unequivocal diagnosis of a stone in the extra-hepatic biliary system, two images in different planes are needed.


Figure 7
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  		Figure 7a.  Residual calculus in a 71-year-old woman after cholecystectomy. (a) Coronal MIP image from a 3D respiratory-triggered T2-weighted fast SE restore data set shows slight dilatation of the intrahepatic bile ducts but does not clearly depict the distal part of the common bile duct (arrows). The round or oval high-signal-intensity structures are cysts in the liver. (b) Thin-section source image obtained with the 3D fast SE restore sequence shows, much more clearly than in a, a filling defect with hypointense signal suggestive of a stone in the distal part of the common bile duct (arrow). (c) Axial free-breathing T2-weighted HASTE image shows a round low-signal-intensity structure (arrow) surrounded by high-signal-intensity fluid in the distal part of the common bile duct.

 

Figure 7
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  		Figure 7b.  Residual calculus in a 71-year-old woman after cholecystectomy. (a) Coronal MIP image from a 3D respiratory-triggered T2-weighted fast SE restore data set shows slight dilatation of the intrahepatic bile ducts but does not clearly depict the distal part of the common bile duct (arrows). The round or oval high-signal-intensity structures are cysts in the liver. (b) Thin-section source image obtained with the 3D fast SE restore sequence shows, much more clearly than in a, a filling defect with hypointense signal suggestive of a stone in the distal part of the common bile duct (arrow). (c) Axial free-breathing T2-weighted HASTE image shows a round low-signal-intensity structure (arrow) surrounded by high-signal-intensity fluid in the distal part of the common bile duct.

 

Figure 7
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  		Figure 7c.  Residual calculus in a 71-year-old woman after cholecystectomy. (a) Coronal MIP image from a 3D respiratory-triggered T2-weighted fast SE restore data set shows slight dilatation of the intrahepatic bile ducts but does not clearly depict the distal part of the common bile duct (arrows). The round or oval high-signal-intensity structures are cysts in the liver. (b) Thin-section source image obtained with the 3D fast SE restore sequence shows, much more clearly than in a, a filling defect with hypointense signal suggestive of a stone in the distal part of the common bile duct (arrow). (c) Axial free-breathing T2-weighted HASTE image shows a round low-signal-intensity structure (arrow) surrounded by high-signal-intensity fluid in the distal part of the common bile duct.

 
Hemorrhage and Hemobilia
Hemorrhage may occur from surgical injury to the liver or from poor hemostasis in the region of the gallbladder bed. Hemorrhage also may result from injury to the hepatic artery, inadequate ligation of the cystic artery, or injury to the portal vein. MR cholangiographic images may depict a normal or displaced but intact biliary tree with an adjacent fluid collection that represents a hematoma (11) (Fig 8). Hemobilia usually results from an invasive procedure (either liver biopsy or percutaneous transhepatic cholangiography). It is a relatively infrequent complication but can lead to a temporary biliary obstruction (Fig 9).


Figure 8
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  		Figure 8.  Hematoma in the gallbladder fossa in a 55-year-old man after cholecystectomy. Axial T1-weighted fat-suppressed volumetric interpolated breath-hold image shows a hypointense fluid collection with an internal peripheral rim of high signal intensity in the gallbladder bed, features suggestive of a hematoma (arrows). The biliary tree is intact.

 

Figure 9
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  		Figure 9a.  Hemobilia after a percutaneous liver biopsy in a 26-year-old man with a liver transplant. (a) Coronal MIP image from a 3D respiratory-triggered T2-weighted fast SE restore data set, obtained 3 days after the biopsy, demonstrates irregular filling defects in the dilated bile ducts (arrowheads) with an intact duct-to-duct anastomosis (arrow) and an intact recipient duct. (b) Axial T1-weighted gradient-recalled-echo MR image shows a curvilinear area of high signal intensity (arrow) along the dilated bile ducts, a finding suggestive of hemobilia. (c) Coronal MIP image from a 3D respiratory-triggered T2-weighted fast SE restore data set, obtained 5 months after the diagnosis of hemobilia, depicts multiple intrahepatic ducts with focal areas of mild dilatation (straight arrows) as well as small biliary lakes (arrowheads), findings suggestive of diffuse cholangitis and bile duct necrosis, which were confirmed at surgery. The recipient duct (curved arrow) appears normal.

 

Figure 9
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  		Figure 9b.  Hemobilia after a percutaneous liver biopsy in a 26-year-old man with a liver transplant. (a) Coronal MIP image from a 3D respiratory-triggered T2-weighted fast SE restore data set, obtained 3 days after the biopsy, demonstrates irregular filling defects in the dilated bile ducts (arrowheads) with an intact duct-to-duct anastomosis (arrow) and an intact recipient duct. (b) Axial T1-weighted gradient-recalled-echo MR image shows a curvilinear area of high signal intensity (arrow) along the dilated bile ducts, a finding suggestive of hemobilia. (c) Coronal MIP image from a 3D respiratory-triggered T2-weighted fast SE restore data set, obtained 5 months after the diagnosis of hemobilia, depicts multiple intrahepatic ducts with focal areas of mild dilatation (straight arrows) as well as small biliary lakes (arrowheads), findings suggestive of diffuse cholangitis and bile duct necrosis, which were confirmed at surgery. The recipient duct (curved arrow) appears normal.

 

Figure 9
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  		Figure 9c.  Hemobilia after a percutaneous liver biopsy in a 26-year-old man with a liver transplant. (a) Coronal MIP image from a 3D respiratory-triggered T2-weighted fast SE restore data set, obtained 3 days after the biopsy, demonstrates irregular filling defects in the dilated bile ducts (arrowheads) with an intact duct-to-duct anastomosis (arrow) and an intact recipient duct. (b) Axial T1-weighted gradient-recalled-echo MR image shows a curvilinear area of high signal intensity (arrow) along the dilated bile ducts, a finding suggestive of hemobilia. (c) Coronal MIP image from a 3D respiratory-triggered T2-weighted fast SE restore data set, obtained 5 months after the diagnosis of hemobilia, depicts multiple intrahepatic ducts with focal areas of mild dilatation (straight arrows) as well as small biliary lakes (arrowheads), findings suggestive of diffuse cholangitis and bile duct necrosis, which were confirmed at surgery. The recipient duct (curved arrow) appears normal.

 
Bile Duct Injuries
Bile duct injuries may be classified as leakage, stricture, or complete transection and excision of a ductal segment, with or without obstruction of the proximal biliary tree by surgical clips.

Bile Leaks.— Injuries after cholecystectomy may be restricted to minor ducts and may not produce any loss of continuity in the biliary tree. Such injuries include bile leaks at the cystic duct or from the gallbladder bed. Bile leaks at the cystic duct may occur when clips on the cystic duct remnant become dislodged or do not encompass the entire duct. Leaks from the gallbladder bed may occur when the plane of dissection on the liver bed is too deep and the small right-sided biliary radicles are injured. Such injury is particularly likely when the presence of an anatomic abnormality (eg, an intrahepatic position of the gallbladder, or an adherent gallbladder due to chronic cholecystitis) makes surgical access difficult (11,12). These types of bile leaks become manifest with pain and sepsis due to the intraperitoneal collection of bile and almost always can be treated successfully with endoscopic sphincterotomy. Injuries to an accessory cystic duct or ducts of Luschka, which usually branch from an accessory right hepatic duct and which connect the gallbladder directly to the right lobe of the liver, also may result in leaks. Misidentification of an aberrant right hepatic duct as the cystic duct may lead to transection without occlusion and thus to a leak that must be treated with the surgical creation of a biliary-enteric anastomosis (Fig 10). A bile leak after cholecystectomy also may result from a tear in a main bile duct. Most often, such a tear is partial and is related to misidentification of the common bile duct as the cystic duct. Such tears may be treated with endoscopic stent placement. Bile leakage after hepatic surgery may originate from the site of a biliary anastomosis, a dislodged or removed external drainage tube (Fig 11), or a bile duct damaged during surgery or trauma. Such leaks represent the most frequent acute biliary complications during the first few weeks after liver transplantation (13). Bile leakage from a biliary-enteric anastomosis is diagnosed when a fluid collection is seen that is independent of the anastomotic jejunal loop and connected to the bile ducts or the anastomosis.


Figure 10
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  		Figure 10a.  Excision injury of a right anterior bile duct in a 24-year-old woman with abdominal pain and fever 6 days after a laparoscopic cholecystectomy. (a) Coronal MIP image from a 3D respiratory-triggered T2-weighted fast SE restore data set shows a mildly dilated and discontinuous right anterior duct (straight arrow) with a bile leak (arrowhead) that was treated with surgical drainage. Note that the right posterior duct is connected with the left hepatic duct (curved arrow). (b) Coronal MIP image from a 3D respiratory-triggered T2-weighted fast SE restore data set obtained 1 month later shows dilatation of the discontinuous right anterior bile duct (arrow), a finding compatible with stricture due to scarring.

 

Figure 10
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  		Figure 10b.  Excision injury of a right anterior bile duct in a 24-year-old woman with abdominal pain and fever 6 days after a laparoscopic cholecystectomy. (a) Coronal MIP image from a 3D respiratory-triggered T2-weighted fast SE restore data set shows a mildly dilated and discontinuous right anterior duct (straight arrow) with a bile leak (arrowhead) that was treated with surgical drainage. Note that the right posterior duct is connected with the left hepatic duct (curved arrow). (b) Coronal MIP image from a 3D respiratory-triggered T2-weighted fast SE restore data set obtained 1 month later shows dilatation of the discontinuous right anterior bile duct (arrow), a finding compatible with stricture due to scarring.

 

Figure 11
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  		Figure 11.  Bile leak due to displacement of a T tube in a 57-year-old man after an orthotopic liver transplantation. Coronal MIP image from a 3D respiratory-triggered T2-weighted fast SE restore data set shows a bile leak (arrows) along the T tube.

 
Bile collections are usually close to the site of the leak, but occasionally they may have a more remote location. The biliary tree may be intact or may show evidence of bile duct injury. The presence of free fluid on the right side of the abdomen, with or without a fluid collection adjacent to the injured bile duct, should be considered suggestive of bile leakage (Fig 12). MR cholangiopancreatography performed without the use of contrast material has been useful in the diagnosis of bile leaks (14); however, it does not provide functional information (15,16) and generally only shows indirect evidence of bile leakage instead of directly depicting it. The utility of the technique also may be limited by its inability to help differentiate bile leaks from ascites, perihepatic fluid collections, and soft-tissue edema, all of which are common in the postoperative period. Several authors have described the use of intravenously administered mangafodipir trisodium for the detection and localization of bile duct leaks at MR cholangiography after bile duct surgery (4,5,13, 16,17). This technique provides both anatomic and functional information about the biliary tract and enables the direct visualization of bile extravasation from injured bile ducts as well as the identification of bile collections (Figs 13, 14).


Figure 12
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  		Figure 12.  Biliary leak through a drain placed in the subhepatic area 3 days after a complex duodenal surgery in a 50-year-old man. Coronal MIP image from a 3D respiratory-triggered T2-weighted fast SE restore data set demonstrates a leak from a branch of the right anterior bile duct (arrow) and a biloma (arrowhead).

 

Figure 13
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  		Figure 13.  Partial tear of the common hepatic duct in a 30-year-old woman with abdominal pain and fever 7 days after a laparoscopic cholecystectomy. Coronal MIP image obtained with a volumetric interpolated breath-hold fat-saturated T1-weighted sequence 1 hour after the intravenous administration of mangafodipir trisodium shows an intact biliary tract with discrete narrowing of the common hepatic duct (straight arrow) and a subhepatic fluid collection (curved arrow) that consists of bile.

 

Figure 14
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  		Figure 14a.  Biloma in a 30-year-old woman after a laparoscopic cholecystectomy. (a) Axial T2-weighted single-shot fast SE MR image shows a small fluid collection with high signal intensity (arrows). (b) Axial T2-weighted single-shot fast SE MR image, acquired 30 minutes after an injection of mangafodipir trisodium, shows extravasated contrast material as a localized pocket of low signal intensity (arrow) within the high-signal-intensity fluid collection, which represents bile.

 

Figure 14
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  		Figure 14b.  Biloma in a 30-year-old woman after a laparoscopic cholecystectomy. (a) Axial T2-weighted single-shot fast SE MR image shows a small fluid collection with high signal intensity (arrows). (b) Axial T2-weighted single-shot fast SE MR image, acquired 30 minutes after an injection of mangafodipir trisodium, shows extravasated contrast material as a localized pocket of low signal intensity (arrow) within the high-signal-intensity fluid collection, which represents bile.

 
 Although mangafodipir trisodium is not currently marketed in the United States, other agents are in various stages of development for the same purpose and may be available in future.

Biliary Injuries from Excision or Ligation.— Laparoscopic cholecystectomy is associated with a large number of biliary injuries. The risk factors for biliary injury due to this surgical procedure are the surgeon’s lack of experience with the laparoscopic technique, inflammation, and anatomic anomalies. Direct causes of bile duct injury include erroneous cutting of a duct, incorrect placement of a surgical clip, and excessive heating (eg, from thermal ablation therapy). There are wide anatomic variations in the extrahepatic biliary tree, some of which may make surgical access difficult. Such anomalies include a low and medial-sided insertion of the cystic duct, a parallel course of the cystic duct alongside the common hepatic duct, and an aberrant right hepatic duct (Figs 15, 16).


Figure 15
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  		Figure 15.  Aberrant right hepatic duct in a 40-year-old woman. Coronal MIP image from a 3D respiratory-triggered T2-weighted fast SE restore data set demonstrates an aberrant right posterior duct (arrows) with a low insertion in the common hepatic duct.

 

Figure 16
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  		Figure 16.  Variant biliary anatomy in a 45-year-old man. Coronal MIP image from a 3D respiratory-triggered T2-weighted fast SE restore data set shows a long cystic duct that parallels and has a rather low insertion in the common hepatic duct (arrows).

 

Bile duct excision and ligation injuries may involve an aberrant right hepatic duct or the main bile ducts. Injuries to the main bile ducts are grouped according to the Bismuth classification system (18). Bismuth types I–IV designate injuries at progressively higher levels of the biliary tree, from the lowest part of the common hepatic duct through the bifurcation into right and left branches, and type V represents injury to a variant right segmental branch with or without involvement of the main duct. Type I designates an injury more than 2 cm distal to the biliary confluence, and type II, an injury less than 2 cm from the biliary confluence. Type III designates injury of the entire common hepatic duct without involvement of the biliary confluence. Type IV represents complete or partial destruction of the biliary confluence (19). The classification of an injury according to the Bismuth system is useful for surgical planning: When a ligation or excision injury is present, the length of the intact common duct distal to the biliary confluence determines whether a choledochojejunostomy or hepaticojejunostomy is performed. When the confluence is involved in the injury, a hepaticojejunostomy is performed, and the confluence is surgically reconstructed. Excision injury is depicted at MR cholangiopancreatography as a persistent discontinuity in a bile duct segment, a finding that should be confirmed by comparing MIP images with the source images. Types of excision injury include biliary excision with bile leakage, partial excision with ductal obstruction, and ductal ligation with obstruction. Complete transection or occlusion of a bile duct is depicted at MR cholangiography as a discontinuity in the extrahepatic bile duct, and ligation of the bile duct is depicted as narrowing or discontinuity in a ductal segment (19) (Figs 17–19). MR cholangiography allows exact definition of the level and length of the biliary injury, information that is essential for preoperative planning;


Figure 17
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  		Figure 17a.  Surgically proved Bismuth type III excision injury with ligation in a 50-year-old woman with right upper quadrant pain and jaundice 3 days after a laparoscopic cholecystectomy. (a) Coronal breath-hold RARE image (20-mm-thick section) shows moderate intrahepatic ductal dilatation, a ductal cutoff due to ligation by a thread just below the biliary confluence, and a bile leak (arrowheads). A 1.5-cm-long segment of the extrahepatic duct is not visible (arrows), a finding suggestive of excision injury. (b) ERCP image shows an abrupt cutoff (arrowhead) of the distal part of the bile duct and contrast material extravasation indicative of bile leakage along a surgically placed drainage tube (arrows).

 

Figure 17
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  		Figure 17b.  Surgically proved Bismuth type III excision injury with ligation in a 50-year-old woman with right upper quadrant pain and jaundice 3 days after a laparoscopic cholecystectomy. (a) Coronal breath-hold RARE image (20-mm-thick section) shows moderate intrahepatic ductal dilatation, a ductal cutoff due to ligation by a thread just below the biliary confluence, and a bile leak (arrowheads). A 1.5-cm-long segment of the extrahepatic duct is not visible (arrows), a finding suggestive of excision injury. (b) ERCP image shows an abrupt cutoff (arrowhead) of the distal part of the bile duct and contrast material extravasation indicative of bile leakage along a surgically placed drainage tube (arrows).

 

Figure 18
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  		Figure 18.  Surgically proved Bismuth type II excision injury with ligation after a laparoscopic cholecystectomy. Coronal MIP image from a 3D respiratory-triggered T2-weighted fast SE restore data set, obtained 1 month after cholecystectomy, shows marked intrahepatic biliary dilatation and a cutoff due to a ligation injury 1 cm distal to the biliary confluence. A 1-cm-long extrahepatic duct segment is not depicted (arrowheads). Note the low insertion site of the right anterior duct in the confluence, at the uppermost point of the hepatic duct (arrow).

 

Figure 19
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  		Figure 19.  Surgically confirmed Bismuth type III excision injury in a 53-year-old woman after a laparoscopic cholecystectomy. Coronal MIP image from a 3D respiratory-triggered T2-weighted fast SE restore data set shows moderate dilatation of the intrahepatic ducts, a cutoff of the common hepatic duct 1 cm below the biliary confluence (thin straight arrow), and a biloma (arrowheads). The distal common bile duct (thick straight arrow) is visible. Drainage of the bile duct is under way through a T tube inserted through the ductal section (curved arrow). Note the low insertion of the right anterior duct. The oval high-signal-intensity structures are cysts in the liver.

 
 however, the length of a bile duct injury may be overestimated in a patient with a peritoneal drain, because the main bile flow is into the drainage tube rather than the extrahepatic duct (5). The signal intensity of the common bile duct distal to the drainage site is weak, and therefore it is difficult to evaluate the duct on MR images.

Late Strictures
Most biliary strictures result in obstructive jaundice or liver dysfunction. Strictures are the most common of the late complications and can develop a few months or many years after surgery (1). A bile duct stricture is defined as a stenosis of the lumen that is judged sufficient to account for abnormal blood chemistry and to impair bile flow (Figs 20, 21). Features that may be associated with biliary stricture include intra- and extrahepatic bile duct dilatation, defined as a diameter of more than 3 or 8 mm, respectively, and without gentle tapering (20,21); ductal narrowing; nondepiction of part of the duct; or an anastomosis with clear depiction of the duct on one side or the other and with stones or sludge in the ducts.


Figure 20
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  		Figure 20.  Stenosis of the papilla after resection of a villous tumor of the papilla and papillotomy in a 55-year-old woman. Coronal MIP image from a 3D respiratory-triggered T2-weighted fast SE restore data set demonstrates dilatation of the main pancreatic duct (straight arrows), subtle irregular narrowing of the distal portion of the common bile duct (curved arrow), and mild dilatation of the common bile duct because of scar formation. The oval high-signal-intensity structures are cysts in the liver.

 

Figure 21
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  		Figure 21a.  Surgically confirmed high-grade stricture of a biliary-enteric anastomosis created for treatment of biliary tract trauma in an 18-year-old man. (a) Coronal oblique RARE MR cholangiographic image (20-mm-thick section) clearly depicts a high-grade stricture of the anastomosis (arrow) with very slight dilatation of the common hepatic duct (8 mm) and normal intrahepatic ducts. (b) Corresponding percutaneous transhepatic cholangiogram helps confirm the high-grade stricture (arrow).

 

Figure 21
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  		Figure 21b.  Surgically confirmed high-grade stricture of a biliary-enteric anastomosis created for treatment of biliary tract trauma in an 18-year-old man. (a) Coronal oblique RARE MR cholangiographic image (20-mm-thick section) clearly depicts a high-grade stricture of the anastomosis (arrow) with very slight dilatation of the common hepatic duct (8 mm) and normal intrahepatic ducts. (b) Corresponding percutaneous transhepatic cholangiogram helps confirm the high-grade stricture (arrow).

 
It is not always possible to distinguish between a stricture and an obstruction with another cause, such as stones or sludge, at MR cholangiography. Because the formation of stones and sludge may be either a cause or an effect of stricture, diagnosis may be particularly difficult. Since MR cholangiography cannot provide functional information or depict resistance to flow, there is a tendency to overestimate the extent of a stricture on the basis of the ductal appearance at MR cholangiography. However, with regard to the use of MR cholangiography as a first-line diagnostic test, the overestimation of a stricture is probably a less serious problem than its underestimation. MR cholangiography also leads to overestimation of the length of a stricture if the duct immediately distal to the stricture has collapsed; however, an analysis of the source images should help avoid or minimize overestimation. While it is important to recognize this potential limitation of MR cholangiography, only the site of the most proximal part of the stricture is relevant, and it is typically the distal extent that is overestimated. The number and location of strictures are important for surgical planning. Strictures may occur after bile duct injury, as a result of bile leakage and scar formation. Main bile duct injuries that are manifested within 1–2 months after surgery are rarely successfully managed with nonsurgical means in the long term unless they are partial stenoses or involve very short ductal segments. Stent placement typically is successful only in the short term (1).

Stricture, the most frequent complication during the late postoperative period after liver transplantation, may arise within several months to several years. The diagnosis of a stricture in the early stages of injury is challenging because clinical and laboratory findings are subtle or even absent. In addition, evaluation of the bile ducts with conventional cholangiographic techniques is associated with an unacceptably high complication rate in patients for whom the level of clinical suspicion is low (22).

The most frequent strictures are of the anastomotic type, and these are usually caused by iatrogenic trauma and scar formation (Fig 22). They may be treated with balloon dilatation and stent placement or with the surgical conversion of a choledochocholedochostomy into a biliary-enteric anastomosis. Some patients present with apparent signs and symptoms of obstruction at the anastomosis after choledochojejunostomy, but on radiologic images the anastomosis appears patent. The cause of functional biliary obstruction is unclear, as information about normal biliary motility is lacking in the literature (9).


Figure 22
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  		Figure 22.  Surgically confirmed stenosis of a duct-to-duct anastomosis in a 39-year-old man 3 months after an orthotopic liver transplantation for hepatocellular carcinoma. Sagittal oblique RARE MR cholangiographic image (20-mm-thick section) shows dilatation of the donor bile duct (straight arrow) and does not clearly depict the anastomosis. A fistula is visible at the site of the anastomosis, and there is a small fluid collection that represents a biloma (arrowheads) anterior to the anastomosis. The distal native common bile duct (curved arrow) also is visible.

 
Nonanastomotic strictures are usually caused by ischemia that is unrelated to iatrogenic bile duct injury. Thrombosis of the hepatic artery is the cause of up to 50% of nonanastomotic strictures. Other causes of nonanastomotic bile duct strictures after liver transplantation include prolonged preservation time, bacterial or viral cholangitis, and rejection. Nonanastomotic strictures are usually hilar stenoses that involve a lengthy ductal segment, including the right and left hepatic ducts and the biliary confluence (Figs 23, 24). They are difficult to manage surgically and usually require dilatation and stent placement. Another pattern that may be manifested is that of biliary necrosis and biloma due to the destruction of the bile ducts and formation of biliary lakes (8,23,24).


Figure 23
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  		Figure 23.  Surgically confirmed nonanastomotic ischemic stricture in a 50-year-old woman with jaundice and abnormal liver function 2 years after a right hepatic lobe transplantation and choledochocholedochostomy and 1 year after stent placement for anastomotic stenosis and hepatic artery thrombosis. Coronal MIP image from a 3D respiratory-triggered T2-weighted fast SE restore data set shows a hilar stricture (straight arrow) with mild dilatation of the intrahepatic ducts and a moderate stricture of the duct-to-duct anastomosis (curved arrow). Note the slight distention of the left hepatic duct remnant (arrowhead). Surgical treatment involved the creation of a biliary-enteric anastomosis between two bile ducts and a jejunal loop.

 

Figure 24
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  		Figure 24a.  Nonanastomotic ischemic stenosis complicated by cholangitis, abscesses, and stones in a 66-year-old man 2 years after an orthotopic liver transplantation. (a) Three-dimensional volumetric MR cholangiographic image shows stones and ductal dilatation (arrowhead) above a high-grade stricture in the left hepatic duct (straight arrow). Abscesses (curved arrows) caused by cholangitis also are visible. (b) Percutaneous transhepatic cholangiogram helps confirm the presence of a high-grade stricture of the left main duct (arrow) and a stone (arrowhead) above the stricture.

 

Figure 24
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  		Figure 24b.  Nonanastomotic ischemic stenosis complicated by cholangitis, abscesses, and stones in a 66-year-old man 2 years after an orthotopic liver transplantation. (a) Three-dimensional volumetric MR cholangiographic image shows stones and ductal dilatation (arrowhead) above a high-grade stricture in the left hepatic duct (straight arrow). Abscesses (curved arrows) caused by cholangitis also are visible. (b) Percutaneous transhepatic cholangiogram helps confirm the presence of a high-grade stricture of the left main duct (arrow) and a stone (arrowhead) above the stricture.

 
Strictures also may occur as late complications of biliary-enteric bypass surgery (Figs 21, 25, 26). MR cholangiopancreatography is particularly valuable in patients with this type of stricture, because endoscopic access is rarely possible and percutaneous transhepatic cholangiography may be associated with an increased risk of complications (1,25). Obstruction of a biliary-enteric anastomosis may be considered complete if intrahepatic biliary ducts are dilated, if there is a signal void between the ducts and a fluid-filled jejunal loop, and if the morphologic features of the anastomosis are not depicted. Recently, it was shown that the MR cholangiographic assessment of the patency of a biliary-enteric anastomosis may be aided by the use of mangafodipir trisodium (25).


Figure 25
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  		Figure 25.  Surgically confirmed high-grade stricture of a choledochoduodenal anastomosis in a 70-year-old woman 8 years after treatment for choledocholithiasis. Thin-section source image obtained with the 3D fast SE restore sequence demonstrates a hypointense filling defect (straight arrow) suggestive of a stone above the tightly constricted hepaticoduodenal anastomosis (curved arrow).

 

Figure 26
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  		Figure 26.  Ischemic stricture due to a pseudoaneurysm with ligation of the hepatic artery during a Whipple procedure for pancreatic carcinoma in a 54-year-old patient. Coronal MIP image from a 3D respiratory-triggered T2-weighted fast SE restore data set demonstrates a long regular stricture in the common hepatic duct and at the origin of the left and right bile ducts (arrow) and moderate dilatation of the intrahepatic ducts. The arrowhead indicates a jejunal loop. A hepaticojejunal anastomosis is not visible.

 
Tumor Recurrence and Metastasis
Biliary obstruction may be related to a recurrent tumor or metastasis in a patient who has a biliary-enteric anastomosis or has undergone a hepatectomy (Fig 27). The obstructed segment may be dilated with a balloon to facilitate the placement of a drainage catheter, but a malignant obstruction is likely to recur rapidly and to require continued catheter drainage. A metal stent may be placed in the duct for palliation and to allow catheter removal, but the stent is likely to become occluded within months (26).


Figure 27
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  		Figure 27a.  Tumor recurrence in a 70-year-old man 1 year after a Whipple procedure for a pancreatic adenocarcinoma. (a) Coronal MIP image from a 3D respiratory-triggered T2-weighted fast SE restore data set shows dilatation of jejunal loops (straight arrows) and intrahepatic bile ducts and narrowing of the bile duct at the confluence (curved arrow). The anastomosis is not visible. (b) Axial T2-weighted fat-suppressed HASTE MR image shows an ill-defined high-signal-intensity hilar metastasis (arrows) from pancreatic adenocarcinoma, which extrinsically compresses the biliary confluence.

 

Figure 27
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  		Figure 27b.  Tumor recurrence in a 70-year-old man 1 year after a Whipple procedure for a pancreatic adenocarcinoma. (a) Coronal MIP image from a 3D respiratory-triggered T2-weighted fast SE restore data set shows dilatation of jejunal loops (straight arrows) and intrahepatic bile ducts and narrowing of the bile duct at the confluence (curved arrow). The anastomosis is not visible. (b) Axial T2-weighted fat-suppressed HASTE MR image shows an ill-defined high-signal-intensity hilar metastasis (arrows) from pancreatic adenocarcinoma, which extrinsically compresses the biliary confluence.

 
Stones
Obstruction of the biliary tree by stones, sludge, or other biliary debris generally is suggestive of the presence of one or more biliary strictures (Fig 25). A biliary-enteric anastomosis, even if patent, may encourage stone formation (Fig 28). Stones are easily recognized as low-signal-intensity structures surrounded by high-signal-intensity bile in the posterior portion of the ducts on axial images. Pneumobilia can be distinguished from calculi because the findings are located in the nondependent portion of the duct on axial images (Fig 29).


Figure 28
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  		Figure 28.  Stone formation near a biliary-enteric anastomosis in a 65-year-old woman after surgical treatment for choledocholithiasis. Coronal breath-hold RARE MR image (20-mm-thick section) shows a patent hepaticojejunal anastomosis (straight arrows) with filling defects in the common hepatic duct and right hepatic duct and at the origin of the left hepatic duct (curved arrows) and residual calculi in the common bile duct (arrowhead). The patency of the hepaticojejunal anastomosis and the presence of multiple stones were confirmed at surgery.

 

Figure 29
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  		Figure 29a.  Pneumobilia after sphincterotomy. (a) Axial T2-weighted HASTE MR image shows linear areas of low signal intensity anterior to the segmental portal veins to hepatic segments II and III (arrows). (b) Coronal MIP image from a 3D respiratory-triggered T2-weighted fast SE restore data set shows the apparent absence of the bile duct to hepatic segment III (arrows). The duct was not visible at MR cholangiopancreatography because it was filled with air.

 

Figure 29
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  		Figure 29b.  Pneumobilia after sphincterotomy. (a) Axial T2-weighted HASTE MR image shows linear areas of low signal intensity anterior to the segmental portal veins to hepatic segments II and III (arrows). (b) Coronal MIP image from a 3D respiratory-triggered T2-weighted fast SE restore data set shows the apparent absence of the bile duct to hepatic segment III (arrows). The duct was not visible at MR cholangiopancreatography because it was filled with air.

 
Small calculi may be obscured on MIP images or thick-slab single-shot RARE images but are readily identified on thin-section source images, which should always be reviewed (Fig 25).

Cholangitis and Abscesses
Ascending cholangitis, which usually is secondary to bacterial contamination of an obstructed biliary system, is diagnosed on the basis of clinical findings. Patients with this condition usually experience abdominal pain, fever, and jaundice, the classic Charcot triad. If an obstruction goes undiagnosed, ascending cholangitis may develop, with intrahepatic bile duct strictures that simulate primary sclerosing cholangitis (depicted as irregularities and a beaded appearance of the major ducts) (Fig 30) (27). Abscesses also may be depicted and may or may not be associated with ascending cholangitis (Fig 24).


Figure 30
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  		Figure 30a.  Cholangitis and secondary infection in a 41-year-old woman after common bile duct injury during a laparoscopic cholecystectomy. (a) Coronal MIP image from a 3D respiratory-triggered T2-weighted fast SE restore data set shows multiple intrahepatic bile duct strictures with irregular mild dilatation of the right intrahepatic ducts and discontinuity of the right bile ducts (straight arrows). An anastomosis (curved arrow) between the left bile duct and a jejunal loop is clearly depicted. (b) Axial T2-weighted HASTE MR image shows atrophy of the right hepatic lobe, scars from previous hepatic abscesses (straight arrow), ill-defined high-signal-intensity areas, and mild dilatation of the distal bile ducts (curved arrows), findings suggestive of infection secondary to cholangitis. The discontinuity of the right bile ducts and the patency of the hepaticojejunal anastomosis were confirmed at surgery.

 

Figure 30
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  		Figure 30b.  Cholangitis and secondary infection in a 41-year-old woman after common bile duct injury during a laparoscopic cholecystectomy. (a) Coronal MIP image from a 3D respiratory-triggered T2-weighted fast SE restore data set shows multiple intrahepatic bile duct strictures with irregular mild dilatation of the right intrahepatic ducts and discontinuity of the right bile ducts (straight arrows). An anastomosis (curved arrow) between the left bile duct and a jejunal loop is clearly depicted. (b) Axial T2-weighted HASTE MR image shows atrophy of the right hepatic lobe, scars from previous hepatic abscesses (straight arrow), ill-defined high-signal-intensity areas, and mild dilatation of the distal bile ducts (curved arrows), findings suggestive of infection secondary to cholangitis. The discontinuity of the right bile ducts and the patency of the hepaticojejunal anastomosis were confirmed at surgery.

 
Mucocele in a Cystic Duct Remnant
During surgical removal of the gallbladder, a closed cystic duct remnant is created. The blind mucosalined cystic duct remnant may become distended with mucus and may impinge on the common hepatic duct, causing biliary obstruction (28). A finding of an extrinsic mass compressing the common hepatic duct is suggestive of a mucocele (Fig 31).


Figure 31
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  		Figure 31.  Surgically confirmed obstructive mucocele of the cystic duct remnant in a 60-year-old woman after cholecystectomy. Coronal MIP image from a 3D respiratory-triggered T2-weighted fast SE restore data set shows a large, distended, irregularly shaped cystic duct remnant (arrows) compressing the common bile duct and causing dilatation of the intra- and extrahepatic ducts.

 

   Conclusions
Top
 Abstract
 LEARNING OBJECTIVES FOR TEST...
 Introduction
 MR Cholangiographic Technique
 Normal Postoperative Findings
 Complications after Surgery
 Conclusions
References
 
MR cholangiopancreatography is a safe and effective method for assessing postoperative alterations in the biliary tract. An understanding of normal postoperative changes in the biliary tract is essential to properly perform the examination and interpret the resultant images. MR cholangiopancreatography, particularly with the use of mangafodipir trisodium as a contrast agent, is of great value for identifying leaks and bilomas as well as bile duct injuries. MR cholangiopancreatography is useful for delineating the anatomy of biliary-enteric anastomoses and detecting complications such as anastomotic strictures, intraductal stones, and ductal dilatation. MR cholangiopancreatography also can be used postoperatively to detect isolated ductal obstructions. Such obstructions may be secondary to strictures or stones, and if an obstruction is high grade or complete, the isolated duct may not be opacified at direct cholangiography. MR cholangiopancreatography also provides a noninvasive means of visualizing primary duct-to-duct anastomoses and biliary-enteric anastomoses as well as complications such as ischemic strictures and intraductal stones in liver transplant recipients.


   Footnotes
 

Abbreviations: ERCP = endoscopic retrograde cholangiopancreatography, HASTE = half-Fourier acquisition single-shot turbo SE, MIP = maximum intensity projection, RARE = rapid acquisition with relaxation enhancement, SE = spin echo, 3D = three-dimensional


   References
Top
 Abstract
 LEARNING OBJECTIVES FOR TEST...
 Introduction
 MR Cholangiographic Technique
 Normal Postoperative Findings
 Complications after Surgery
 Conclusions
 References
 

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