Intérêt de l’IRM avec perfusion de mangafodipir trisodium dans la détection des fuites biliaires

[A case study of post-traumatic common bile duct injury: an unusual lesion]

La section traumatique du cholédoque est un phénomène extrêmement rare surtout lorsqu'elle est isolée. Habituellement, elle survient suite à une chirurgie des voies biliaires notamment laparoscopique. Cette lésion est souvent associée à une ou plusieurs lésions des organes de voisinage. Nous rapportons un cas de section isolée du cholédoque suite à un traumatisme abdominal chez un enfant âgé de 5 ans pris en charge dans notre service au Centre Hospitalier Mère et Enfant de Nouakchott. L'exploration radiologique n'était concluante. Une laparotomie exploratrice faite devant un tableau chirurgical a révélé une péritonite généralisée d'origine biliaire secondaire à une plaie du bas cholédoque. Le traitement d'urgence était une toilette avec une dérivation biliaire externe suivie à un mois après par une dérivation bilio-digestive. La complication la plus redoutable de section de cholédoque est la péritonite biliaire. La morbidité postopératoire précoce est de l'ordre de 20 à 30% dans la littérature alors que la mortalité est de 0 à 2%. La section traumatique isolée du cholédoque chez l'enfant est une lésion dont le tableau clinique et la conduite thérapeutique doivent être connus afin de diminuer la morbi-mortalité. La prise charge doit être multidisciplinaire impliquant le chirurgien pédiatre, le radiologue et le réanimateur anesthésiste.

Advantages of gadobenate dimeglumine-enhanced MR cholangiography in the diagnosis of post-liver transplant bile leakage

OBJECTIVE

To assess the value of magnetic resonance cholangiography with gadobenate dimeglumine (Gd-BOPTA) where there is a suspicion of bile leakage in the post-liver transplant patient.

PATIENTS AND METHODS

Eight patients who had undergone a liver transplant underwent 14 MR cholangiograms, five of whom presented bile leakage while the other three had no biliary system complications. The results were compared to conventional bile duct opacification (by endoscopy or t-tube cholangiogram). The analysis covered whether there was opacification of the common bile duct and intrahepatic bile ducts on T1-weighted sequences after an injection of Gd-BOPTA on delayed biliary excretion phase sequences that were carried out on average 74 min after the injection. Enhancing perihepatic collections were also taken into account.

RESULTS

Opacification of the bile ducts on delayed-phase MR cholangiogram sequences was always seen in the absence of bile leakage, and was never found when leakage was present. Enhancing perihepatic collections pointed to bile leakage every time.

CONCLUSION

Gd-BOPTA-enhanced MR cholangiography is a simple and non-invasive technique for detecting bile leakage in the post-liver transplant patient.

[Imaging of the postoperative biliary tract]

For a long time, imaging of the biliary tract after surgical procedures was performed with invasive procedures such as endoscopic retrograde cholangiopancreatography or percutaneous transhepatic cholangiography. Due to recent advances in diagnostic imaging, non-invasive techniques are now favored. While US remains the initial imaging modality, it is frequently followed by CT and/or MRCP. Image interpretation should always be performed in keeping with clinical and laboratory findings as well as the type of surgical procedure. The most appropriate imaging modality is selected based on these data. In patients with jaundice or biliary tract stenosis, MRCP, with use of an optimal technique and 3D acquisition, is the imaging modality of choice. In non-jaundiced patients with non-distended biliary tract and suspected bile leak, MRCP should be completed by the injection of a liver-specific contrast agent with biliary excretion to achieve non-invasive biliary tract opacification. In patients with malignancy, CT is preferred due to its high spatial resolution and ability to demonstrate small anastomotic tumor recurrences. CT should also be performed in patients with suspected hepatic artery or portal vein injury in addition to biliary tract injury or to detect distant complications.

[Value of MRCP for diagnosis of biliary complications after liver transplantation]

PURPOSE

To assess the value of MRCP in the detection of biliary complications after orthotopic liver transplantation.

MATERIALS AND METHODS

27 transplanted patients with suspected biliary complication underwent a total of 34 MR and direct cholangiography procedures. MRCP were reviewed by 2 independent reviewers blinded to clinical and laboratory findings. The biliary tract was divided into 7 segments, and all lesions were evaluated using this segmental anatomy. Each segment was evaluated for the presence of dilatation, stenosis and intra-ductal debris. MRCP results were compared to results frpm direct cholangiography.

RESULTS

216 (98%) of 221 biliary segments could be evaluated on MRCP, with good to excellent visualization in 179 (80%) cases. Segmental analysis showed sensitivity, specificity and accuracy values of 85%, 81% and 83% for the detection of biliary stenosis, 82%, 81% and 81% for the detection of biliary dilatation, and 60%, 88% and 80% for the detection of inyraductal debris.

CONCLUSION

MRCP is accurate for the detection of biliary stenosis and dilatation in patients after liver transplantation and provides an alternative to direct cholangiography.

[Pineapple juice as a negative oral contrast agent in magnetic resonance cholangiopancreatography]

PURPOSE

The quality of magnetic resonance cholangiopancreatography (MRCP) images is frequently degraded by high signal from the gastrointestinal tract on heavily T2W images. The purpose of this study is to evaluate pineapple juice (PJ) as an oral negative contrast agent in MRCP.

MATERIALS AND METHODS

Results from MRCP in 50 patients with PJ and 50 patients with paramagnetic contrast (ferumoxsil-Lumirem) were compared. Reviewers were blinded to the type of contrast agent. Exam quality was recorded with regards to signal suppression in the stomach, duodenum and proximal small bowel and with regards to pancreatic duct and biliary ducts visualization. In vitro, the signal characteristics of several commercially available brands of PJ were assessed using T1W, T2W and MRCP sequences. Signal intensity was correlated with the manganese concentration measured using atomic absorption spectrometry. Finally, the reviewers compared the taste of PJ and ferumoxsil.

RESULTS

On MRCP sequences, results were similar with regards to signal suppression in the stomach, duodenum and proximal small bowel with PJ and ferumoxsil. Visualization of the pancreatic duct, intrahgepatic bile ducts and CBD was similar with PJ and ferumoxsil. The signal intensity of commercially available brands of PJ on T2W and MRCP sequences correlated well with the measured manganese concentration on spectroscopy. Variations in manganese concentration were observed, with values ranging from 3.65 to 27.24 mg/L. The reviewers noted that PJ tasted "good" or "very good" and that ferumoxsil tasted "bad" or "very bad".

CONCLUSION

Ingestion of PJ provides effective signal suppression in the GI tract on MRCP, similar to paramagnetic contrast agents. Because manganese concentration is highly variable in commercially available PJ brands, a brand with high manganese concentration should be selected.

Hepatobiliary scintigraphy in detecting lesser sac bile leak in postcholecystectomy patients: the need to recognize as a separate entity

Cholecystectomy is one of the most commonly performed abdominal surgeries in which bile duct injury and bile leaks are the most important complications. Imaging plays an important role in the prompt diagnosis and management of bile leaks. The more common sites of bile leak are the gallbladder bed, subhepatic, in a bilioma, right paracolic gutter, or diffusely in the peritoneal cavity. Bile leak into the lesser sac (LS) is uncommon but is a special entity posing difficult problems in management. We have described in this study the clinical presentation, imaging findings, and management of 6 patients with biliary leakage into the LS postcholecystectomy. The clinical presentation of this condition was varied, ranging from patients with asymptomatic or with vague complaints resulting in difficulties in clinical suspicion or symptomatic but minimal enough not to be detected by ultrasonogram. Hepatobiliary scintigraphy played an important role in the diagnosis and management, and all patients required definitive therapeutic drainage procedures. Any persistent focal radiotracer activity in the anatomy of the LS, increasing with time and not diffusing into the general peritoneal cavity is diagnostic of bile leak into the LS.

[New possibilities to study biliary tree and gallbladder: functional magnetic resonance cholangiography contrast-enhanced with mangafodipir trisodium (Mn DPDP)]

Mangafodipir trisodium (Teslascan) is a hepatobiliary contrast agent that provides noninvasive opacification of the bile ducts. Using this contrast medium combined with a T1-weighted gradient echo enhanced sequence provides functional imaging of the bile ducts. Second-intention MRI was obtained after the usual morphological study of the bile ducts using heavily T2-weighted sequences (SS-FSE Te eff long and SS FSE Te eff short). This method can detect many biliary duct anomalies: biliary leakage in the postoperative context, mapping of bile ducts and the gallbladder in the search for anatomical variants, analysis of biliodigestive or biliobiliary anastomoses, or a dynamic study of bile secretion and excretion. Opacification of the bile ducts has only been possible until now with invasive tests aggravated by a certain co-morbidity rate and their functional study using biliary scintigraphy limited by mediocre spatial resolution. This new possibility provides access not only to morphological imaging, but also to functional imaging with excellent spatial resolution.

Normal and pathologic features of the postoperative biliary tract at 3D MR cholangiopancreatography and MR imaging

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.