Magnetic resonance cholangiography of biliary strictures after liver transplantation: a prospective double-blind study

Atlas for Cholangioscopy and Cholecystoscopy: A Primer for Diagnostic and Therapeutic Endoscopy in the Biliary Tree and Gallbladder

Percutaneous endoscopy of the biliary system (cholangioscopy) and gallbladder (cholecystoscopy) has significantly impacted diagnostic and therapeutic approaches to many diseases in interventional radiology, overcoming previous challenges related to scope size and rigidity. The current endoscopes offer enhanced maneuverability within narrow tubular structures such as bile ducts. Before endoscopy, reliance on 2D imaging modalities limited real-time visualization during percutaneous procedures. Percutaneous endoscopy provides 3D perspectives, enabling a better appreciation of normal structures, targeted biopsy of lesions, and accurate deployment of therapeutic interventions. This review aims to explore percutaneous endoscopic findings across various biliary and gallbladder pathologies.

American Society for Gastrointestinal Endoscopy guideline on management of post-liver transplant biliary strictures: summary and recommendations

This clinical practice guideline from the American Society for Gastrointestinal Endoscopy provides an evidence-based approach for strategies to manage biliary strictures in liver transplant recipients. This document was developed using the Grading of Recommendations Assessment, Development and Evaluation framework. The guideline addresses the role of ERCP versus percutaneous transhepatic biliary drainage and covered self-expandable metal stents (cSEMSs) versus multiple plastic stents for therapy of post-transplant strictures, use of MRCP for diagnosing post-transplant biliary strictures, and administration of antibiotics versus no antibiotics during ERCP. In patients with post-transplant biliary strictures, we suggest ERCP as the initial intervention and cSEMSs as the preferred stent for extrahepatic strictures. In patients with unclear diagnoses or intermediate probability of a stricture, we suggest MRCP as the diagnostic modality. We suggest that antibiotics should be administered during ERCP when biliary drainage cannot be ensured.

American Society for Gastrointestinal Endoscopy guideline on management of post-liver transplant biliary strictures: methodology and review of evidence

This clinical practice guideline from the American Society for Gastrointestinal Endoscopy provides an evidence-based approach for strategies to manage biliary strictures in liver transplant recipients. This document was developed using the Grading of Recommendations Assessment, Development and Evaluation framework. The guideline addresses the role of ERCP versus percutaneous transhepatic biliary drainage and covered self-expandable metal stents (cSEMSs) versus multiple plastic stents for therapy of strictures, use of MRCP for diagnosing post-transplant biliary strictures, and administration of antibiotics versus no antibiotics during ERCP. In patients with post-transplant biliary strictures, we suggest ERCP as the initial intervention and cSEMSs as the preferred stent. In patients with unclear diagnosis or intermediate probability of a stricture, we suggest MRCP as the diagnostic modality. We suggest that antibiotics should be administered during ERCP when biliary drainage cannot be assured.

Post-Transplant Biliary Strictures: An Updated Review

Liver transplantation (LT) is the only curative therapy in patients with end-stage liver disease with excellent long-term survival; however, LT recipients are at risk of significant complications. Among these complications are biliary complications with an incidence ranging from 5 to 32% and associated with significant post-LT morbidity and mortality. Prompt recognition and management are critical as these complications have been associated with mortality rates up to 19% and retransplantation rates up to 13%. An important limitation of published studies is that a large proportion does not discriminate between anastomotic strictures and nonanastomotic strictures. This review aims to summarize our current understanding of risk factors and natural history, diagnostic testing, and treatment options for post-LT biliary strictures.

Biliary complications after liver transplantation: current perspectives and future strategies

Importance

Liver transplantation (LT) is a life-saving therapy for patients with end-stage liver disease and with acute liver failure, and it is associated with excellent outcomes and survival rates at 1 and 5 years. The incidence of biliary complications (BCs) after LT is reported to range from 5% to 20%, most of them occurring in the first three months, although they can occur also several years after transplantation.

Objective

The aim of this review is to summarize the available evidences on pathophysiology, risk factors, diagnosis and therapeutic management of BCs after LT.

Evidence Review

a literature review was performed of papers on this topic focusing on risk factors, classifications, diagnosis and treatment.

Findings

Principal risk factors include surgical techniques and donor's characteristics for biliary leakage and anastomotic biliary strictures and vascular alterations for non- anastomotic biliary strictures. MRCP is the gold standard both for intra- and extrahepatic BCs, while invasive cholangiography should be restricted for therapeutic uses or when MRCP is equivocal. About treatment, endoscopic techniques are the first line of treatment with success rates of 70-100%. The combined success rate of ERCP and PTBD overcome 90% of cases. Biliary leaks often resolve spontaneously, or with the positioning of a stent in ERCP for major bile leaks.

Conclusions and Relevance

BCs influence morbidity and mortality after LT, therefore further evidences are needed to identify novel possible risk factors, to understand if an immunological status that could lead to their development exists and to compare the effectiveness of innovative surgical and machine perfusion techniques.

The real incidence of biliary tract complications after adult liver transplantation: the role of the prospective routine use of cholangiography during post-transplant follow-up

Biliary tract complications (BTCs) still burden liver transplantation (LT). The wide reporting variability highlights the absence of systematic screening. From 2000 to 2009, simultaneous liver biopsy and direct biliary visualization were prospectively performed in 242 recipients at 3 and 6 months (n = 212, 87.6%) or earlier when indicated (n = 30, 12.4%). Median follow-up was 148 (107-182) months. Seven patients (2.9%) experienced postprocedural morbidity. BTCs were initially diagnosed in 76 (31.4%) patients; 32 (42.1%) had neither clinical nor biological abnormalities. Acute cellular rejection (ACR) was present in 27 (11.2%) patients and in 6 (22.2%) BTC patients. Nine (3.7%) patients with normal initial cholangiography developed BTCs after 60 (30-135) months post-LT. BTCs directly lead to 7 (2.9%) re-transplantations and 14 (5.8%) deaths resulting in 18 (7.4%) allograft losses. Bile duct proliferation at 12-month biopsy proved an independent risk factor for graft loss (P = 0.005). Systematic biliary tract and allograft evaluation allows the incidence and extent of biliary lesions to be documented more precisely and to avoid erroneous treatment of ACR. The combination 'abnormal biliary tract-canalicular proliferation' is an indicator of worse graft outcome. BTCs are responsible for important delayed allograft and patient losses. These results underline the importance of life-long follow-up and appropriate timing for re-transplantation.

Quantitative MRCP Imaging: Accuracy, Repeatability, Reproducibility, and Cohort-Derived Normative Ranges

BACKGROUND

Magnetic resonance cholangiopancreatography (MRCP) is an important tool for noninvasive imaging of biliary disease, however, its assessment is currently subjective, resulting in the need for objective biomarkers.

PURPOSE

To investigate the accuracy, scan/rescan repeatability, and cross-scanner reproducibility of a novel quantitative MRCP tool on phantoms and in vivo. Additionally, to report normative ranges derived from the healthy cohort for duct measurements and tree-level summary metrics.

STUDY TYPE

Prospective.

PHANTOMS/SUBJECTS

Phantoms: two bespoke designs, one with varying tube-width, curvature, and orientation, and one exhibiting a complex structure based on a real biliary tree. Subjects Twenty healthy volunteers, 10 patients with biliary disease, and 10 with nonbiliary liver disease.

SEQUENCE/FIELD STRENGTH

MRCP data were acquired using heavily T2 -weighted 3D multishot fast/turbo spin echo acquisitions at 1.5T and 3T.

ASSESSMENT

Digital instances of the phantoms were synthesized with varying resolution and signal-to-noise ratio. Physical 3D-printed phantoms were scanned across six scanners (two field strengths for each of three manufacturers). Human subjects were imaged on four scanners (two fieldstrengths for each of two manufacturers).

STATISTICAL TESTS

Bland-Altman analysis and repeatability coefficient (RC).

RESULTS

Accuracy of the diameter measurement approximated the scanning resolution, with 95% limits of agreement (LoA) from -1.1 to 1.0 mm. Excellent phantom repeatability was observed, with LoA from -0.4 to 0.4 mm. Good reproducibility was observed across the six scanners for both phantoms, with a range of LoA from -1.1 to 0.5 mm. Inter- and intraobserver agreement was high. Quantitative MRCP detected strictures and dilatations in the phantom with 76.6% and 85.9% sensitivity and 100% specificity in both. Patients and healthy volunteers exhibited significant differences in metrics including common bile duct (CBD) maximum diameter (7.6 mm vs. 5.2 mm P = 0.002), and overall biliary tree volume 12.36 mL vs. 4.61 mL, P = 0.0026).

DATA CONCLUSION

The results indicate that quantitative MRCP provides accurate, repeatable, and reproducible measurements capable of objectively assessing cholangiopathic change. Evidence Level: 1 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2020;52:807-820.

Imaging post liver transplantation part II: biliary complications

Biliary complications post liver transplantation are a significant source of morbidity and mortality and early recognition is paramount to the long-term success of the liver graft. Part II of this series will focus on liver transplant biliary anatomy, including the blood supply to the biliary system and potential problems if it is interrupted. The imaging rationale for investigating suspected biliary complications, potential pitfalls, and treatment options will be discussed. The various biliary complications will be illustrated using a collection of cases.

Is Surgery Necessary? Endoscopic Management of Post-transplant Biliary Complications in the Modern Era

BACKGROUND

Biliary complications are common following liver transplantation (LT) and traditionally managed with Roux-en-Y hepaticojejunostomy. However, endoscopic management has largely supplanted surgical revision in the modern era. Herein, we evaluate our experience with the management of biliary complications following LT.

METHODS

All LTs from January 2013 to June 2018 at a single institution were reviewed. Patients with biliary bypass prior to, or at LT, were excluded. Patients were grouped by biliary complication of an isolated stricture, isolated leak, or concomitant stricture and leak (stricture/leak).

RESULTS

A total of 462 grafts were transplanted into 449 patients. Ninety-five (21%) patients had post-transplant biliary complications, including 56 (59%) strictures, 28 (29%) leaks, and 11 (12%) stricture/leaks. Consequently, the overall stricture, leak, and stricture/leak rates were 12%, 6%, and 2%, respectively. Endoscopic management was pursued for all stricture and stricture/leak patients, as well as 75% of leak patients, reserving early surgery only for those patients with an uncontrolled leak and evidence of biliary peritonitis. Endoscopic management was successful in the majority of patients (stricture 94%, leak 90%, stricture/leak 90%). Only six patients (5.6%) received additional interventions-two required percutaneous transhepatic cholangiography catheters, three underwent surgical revision, and one was re-transplanted.

CONCLUSIONS

Endoscopic management of post-transplant biliary complications resulted in long-term resolution without increased morbidity, mortality, or graft failure. Successful endoscopic treatment requires collaboration with a skilled endoscopist. Moreover, multidisciplinary transplant teams must develop treatment protocols based on the local availability and expertise at their center.

Biliary Complications After Liver Transplantation From Uncontrolled Donors After Circulatory Death: Incidence, Management, and Outcome

The utilization of livers from donation after uncontrolled circulatory death (uDCD) increases the availability of liver grafts, but it is associated with a higher incidence of biliary complications (BCs) and lower graft survival than those organs donated after brain death. From January 2006 to December 2016, we performed 75 orthotopic liver transplantations (OLTs) using uDCD livers. To investigate the relationship of BCs with the use of uDCD OLT, we compared patients who developed BCs (23 patients) with those who did not (non-BC group, 43 patients) after excluding cases of hepatic artery thrombosis (a known cause of BC) and primary nonfunction. The groups had similar uDCD donor maintenance, donor and recipient characteristics, and perioperative morbidity/mortality rates, but we observed a higher rate of hepatocellular carcinoma and hepatitis C virus in the non-BC group. Percutaneous transhepatic biliary dilation, endoscopic retrograde cholangiopancreatography dilation, Roux-en-Y hepaticojejunostomy (HJ), a T-tube, and retransplantation were used for BC management. In the BC group, 1-, 3-, and 5-year patient survival rates were 91.3%, 69.6%, and 65.2%, respectively, versus 77.8%, 72.9%, and 72.9%, respectively, in the non-BC group (P = 0.89). However, 1-, 3-, and 5-year graft survival rates were 78.3%, 60.9%, and 56.5%, respectively, in the BC group versus 77.8%, 72.9%, and 72.9%, respectively, in the non-BC group (P = 0.38). Multivariate analysis did not indicate independent risk factors for BC development. In conclusion, patient and graft survival rates were generally lower in patients who developed BCs but not significantly so. These complications were managed in the majority of patients through radiological dilation, endoscopic dilation, or Roux-en-Y HJ. Retransplantation is necessary in rare cases after the failure of biliary dilation or surgical procedures.

Role of MRCP in Diagnosing Biliary Anastomotic Strictures After Liver Transplantation: A Single Tertiary Care Center Experience

BACKGROUND

Biliary strictures (BS) are common complication after liver transplantation. We aimed to determine the accuracy of magnetic resonance cholagiopancreatography (MRCP) in diagnosing BS in liver transplant recipients (LTRs) when compared to direct cholangiographic methods (endoscopic resonance cholagiopancreatography [ERCP] and/or percutaneous transhepatic cholangiography [PTC]).

METHODS

Retrospective chart review of 910 LTRs (July 2008 to April 2015) was performed, and a total of 39 patients with duct-to-duct anastomosis (22 males; 56.4%; mean age, 52.8 ± 8.3 years) were included who had an MRCP followed by either ERCP and/or PTC within 4 weeks. A cholangiographic narrowing (on ERCP and/or PTC) that required balloon dilation and/or stent placement was considered a BS and was considered clinically significant if the intervention resulted in at least 30% improvement of bilirubin within 2 weeks. Sensitivity, specificity, accuracy, positive predictive values and negative predictive values of MRCP in diagnosing BS were calculated.

RESULTS

Magnetic resonance cholagiopancreatography showed anastomotic BS in 17 of 39 patients, and subsequent ERCP and/or PTC revealed a total of 25 BS (positive predictive value of 0.94). Nine BS on cholangiography (ERCP, 8; PTC, 1) were not detected on earlier MRCP (sensitivity, 0.64; 95% CI, 0.45-0.82); 2 were clinically significant BS and 6 of the remaining 7 had no improvement in their liver function test with biliary intervention. Thirteen LTRs had no BS on either modality (specificity, 0.93; 95% CI, 0.66-0.99). The negative predictive value of MRCP was 0.59 for cholangiographic BS. The overall accuracy of MRCP is 0.74 (exact 95% CI, 0.58-0.87). Inclusion of age, race, and alanine aminotransferase level improved the predictive value of MRCP (area under the curve = 0.94, 95% CI: 0.86-1.00).

CONCLUSIONS

Magnetic resonance cholagiopancreatography has high specificity but low sensitivity in diagnosing cholangiographic BS in LTRs, although the predictive value further improved with inclusion of age, race, and alanine aminotransferase. Clinical significance of BS in LTRs not identified on MRCP is questionable because ERCP with intervention did not improve their liver function tests in the vast majority.

Risk factors and clinical indicators for the development of biliary strictures post liver transplant: Significance of bilirubin

AIM

To identify risk factors associated with the formation of biliary strictures post liver transplantation over a period of 10-year in Queensland.

METHODS

Data on liver donors and recipients in Queensland between 2005 and 2014 was obtained from an electronic patient data system. In addition, intra-operative and post-operative characteristics were collected and a logistical regression analysis was performed to evaluate their association with the development of biliary strictures.

RESULTS

Of 296 liver transplants performed, 285 (96.3%) were from brain dead donors. Biliary strictures developed in 45 (15.2%) recipients. Anastomotic stricture formation (n = 25, 48.1%) was the commonest complication, with 14 (58.3%) of these occurred within 6-mo of transplant. A percutaneous approach or endoscopic retrograde cholangiography was used to treat 17 (37.8%) patients with biliary strictures. Biliary reconstruction was initially or ultimately required in 22 (48.9%) patients. In recipients developing biliary strictures, bilirubin was significantly increased within the first post-operative week (Day 7 total bilirubin 74 μmol/L vs 49 μmol/L, P = 0.012). In both univariate and multivariate regression analysis, Day 7 total bilirubin > 55 μmol/L was associated with the development of biliary stricture formation. In addition, hepatic artery thrombosis and primary sclerosing cholangitis were identified as independent risk factors.

CONCLUSION

In addition to known risk factors, bilirubin levels in the early post-operative period could be used as a clinical indicator for biliary stricture formation.

Biliary complications after liver transplantation; recent developments in etiology, diagnosis and endoscopic treatment

Biliary complications are considered to be the Achilles' heel of liver transplantation. The most common complications are leaks and bile duct strictures. Strictures can arise at the level of the anastomosis (anastomotic strictures; AS) or at other locations in the biliary tree (non-anastomotic strictures; NAS). Endoscopic treatment via endoscopic retrograde cholangiopancreatography (ERCP) is considered to be the preferred therapy for these complications. This review will focus on the diagnostic modalities, new insights in etiology of biliary complications and outcomes after different endoscopic therapies, in both deceased donor transplantation and living-donor liver transplantations. Advances in recent therapies, such as the use of self-expendable metal stents (SEMS) and endoscopic therapy for patients with a bilio-digestive anastomosis will be discussed.

Evaluation of biliary complications on magnetic resonance cholangiopancreatography and comparison with direct cholangiography after living-donor liver transplantation

AIM

To evaluate the imaging characteristics of biliary complications following liver transplantation on magnetic resonance cholangiopancreatography (MRCP) and its diagnostic accuracy in comparison with direct cholangiography.

MATERIAL AND METHODS

In this prospective study, 34 patients being evaluated for possible biliary complications after living-donor liver transplantation (LDLT) with abnormal MRCP findings were followed up for information regarding direct cholangiography either endoscopic retrograde cholangiopancreatography (ERCP) or percutaneous transhepatic cholangiography (PTC) within 7 days of MRCP. Twenty-nine patients underwent ERCP and five patients underwent PTC.

RESULTS

Compared to findings at direct cholangiography, MRCP presented 96.9% sensitivity, 96.9% positive predictive value, and 94.1% accuracy for the detection of biliary complications. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy for detection of anastomotic strictures, biliary leak, and biliary stone or sludge on MRCP was found to be 100%, 84.6%, 91.3%, 100% and 94.1%; 72.7%, 95.7%, 88.9%, 88% and 88.2%; 80%, 100%, 100%, 96.7% and 97.1%, respectively.

CONCLUSION

MRCP is a reliable non-invasive technique to evaluate the biliary complications following LDLT. MRCP should be the imaging method of choice for diagnosis in this setting and direct cholangiography should be reserved for cases that need therapeutic interventions.

Management issues in post living donor liver transplant biliary strictures

Biliary complications are common after living donor liver transplant (LDLT) although with advancements in surgical understanding and techniques, the incidence is decreasing. Biliary strictures are more common than leaks. Endoscopic retrograde cholangiopancreatography (ERCP) is the first line modality of treatment of post LDLT biliary strictures with a technical success rate of 75%-80%. Most of ERCP failures are successfully treated by percutaneous transhepatic biliary drainage (PTBD) and rendezvous technique. A minority of patients may require surgical correction. ERCP for these strictures is technically more challenging than routine as well post deceased donor strictures. Biliary strictures may increase the morbidity of a liver transplant recipient, but the mortality is similar to those with or without strictures. Post transplant strictures are short segment and soft, requiring only a few session of ERCP before complete dilatation. Long-term outcome of patients with biliary stricture is similar to those without stricture. With the introduction of new generation cholangioscopes, ERCP success rate may increase, obviating the need for PTBD and surgery in these patients.

Endoscopic management of post-liver transplant billiary complications: A prospective study from tertiary centre in India

BACKGROUND

Liver transplantation has become common in India over the last decade and biliary strictures after the procedure cause a significant morbidity. Endoscopic retrograde cholangiopancreatography (ERCP) is a safe and effective treatment modality for post-transplant biliary strictures so we decided to evaluate prospectively the outcomes of endoscopic treatment in post-living donor liver transplantation (LDLT) biliary strictures.

METHODS

We studied ten consecutive patients who had developed biliary strictures (out of 312 who had undergone liver transplantation between June 2009 and June 2013) and had been referred to the Department of Gastroenterology for management. All patients underwent liver function tests, ultrasound of the abdomen, magnetic resonance cholangiography and liver biopsy, if this was indicated.

RESULTS

Of these 312 patients who underwent liver transplantation, 305 had living donors (LDLT) and 7 deceased donors (DDLT). Ten patients in the LDLT group (3.3%) developed biliary strictures. There were seven males and three females who had median age of 52 years (range 4-60 years). The biliary anastomosis was duct-to-duct in all patients with one patient having an additional duct-to-jejunum anastomosis. The mode of presentation was cholangitis in four patients (40%), asymptomatic elevation of liver enzymes in four (40%) and jaundice in two patients (20%). The median time from transplantation to the detection of the stricture was 12 months (2-42.5 months). ERCP was attempted as initial therapy in all patients: seven were managed entirely by endoscopic therapy, and three required a combined percutaneous and endoscopic approach. Cholangiography demonstrated anastomotic stricture in all patients. A total of 32 sessions of ERCP were done with mean of 3.2 (2-5) endoscopic sessions and 3.4 (1-6) stents required to resolve the stricture. The median time from the first intervention to stricture resolution was 4 months (range 2-12 months). In four patients, the stents were removed after one session and in two patients each after two, three and four sessions. In six patients more than one stent was placed and all of them required dilatation of stricture. Seven patients completed treatment and are off stents at a median follow up period of 9.5 months (7-11 months). Two patients developed recurrence of their stricture after 7.5 months. Both had long strictures and required a combined endoscopic and percutaneous approach. There was one mortality due to sepsis secondary to cholangitis.

CONCLUSIONS

Post-LDLT biliary strictures can be successfully treated with ERCP, and most patients remain well on follow up (median 9.5 months). A combined endoscopic and percutaneous approach is useful when ERCP alone fails.

Value of Magnetic Resonance Cholangiopancreatography in Assessment of Nonanastomotic Biliary Strictures After Liver Transplantation

Nonanastomotic biliary strictures (NAS) remain a frequent complication after orthotopic liver transplantation (OLT). The aim of this study was to evaluate whether magnetic resonance cholangiopancreatography (MRCP) could be used to detect NAS and to grade the severity of biliary strictures.

Pediatric Biliary Interventions

An interventional radiologist is frequently called to evaluate and treat biliary diseases in children; a tailored approach specific to this population is required. Imaging with an emphasis on minimizing ionizing radiation is used not only in the initial workup but also to guide interventions. The most common form of intervention generally consists of transhepatic biliary drainage to treat either biliary obstruction or bile leakage, a scenario frequently encountered after pediatric liver transplantation. Other pathologies referred for evaluation and management include biliary atresia and, rarely, symptomatic choledochal cysts. Biliary complications caused by an underlying malignancy are not a frequently encountered problem in the pediatric population. The initial evaluation, role of preprocedural imaging, and interventional management with an emphasis on technique are discussed regarding these common biliary pathologies in children.

Endoscopic management of post-liver transplant biliary complications

Biliary complications are being increasingly encountered in post liver transplant patients because of increased volume of transplants and longer survival of these recipients. Overall management of these complications may be challenging, but with advances in endoscopic techniques, majority of such patients are being dealt with by endoscopists rather than the surgeons. Our review article discusses the recent advances in endoscopic tools and techniques that have proved endoscopic retrograde cholangiography with various interventions, like sphincterotomy, bile duct dilatation, and stent placement, to be the mainstay for management of most of these complications. We also discuss the management dilemmas in patients with surgically altered anatomy, where accessing the bile duct is challenging, and the recent strides towards making this prospect a reality.

Adult bile duct strictures: role of MR imaging and MR cholangiopancreatography in characterization

Bile duct strictures in adults are secondary to a wide spectrum of benign and malignant pathologic conditions. Benign causes of bile duct strictures include iatrogenic causes, acute or chronic pancreatitis, choledocholithiasis, primary sclerosing cholangitis, IgG4-related sclerosing cholangitis, liver transplantation, recurrent pyogenic cholangitis, Mirizzi syndrome, acquired immunodeficiency syndrome cholangiopathy, and sphincter of Oddi dysfunction. Malignant causes include cholangiocarcinoma, pancreatic adenocarcinoma, and periampullary carcinomas. Rare causes include biliary inflammatory pseudotumor, gallbladder carcinoma, hepatocellular carcinoma, metastases to bile ducts, and extrinsic bile duct compression secondary to periportal or peripancreatic lymphadenopathy. Contrast material-enhanced magnetic resonance (MR) imaging with MR cholangiopancreatography is extremely helpful in the noninvasive evaluation of patients with obstructive jaundice, an obstructive pattern of liver function, or incidentally detected biliary duct dilatation. Some of these conditions may show characteristic findings at MR imaging-MR cholangiopancreatography that help in making a definitive diagnosis. Although endoscopic retrograde cholangiopancreatography with tissue biopsy or surgery is needed for the definitive diagnosis of many of these strictures, certain MR imaging characteristics of the narrowed segment (eg, thickened wall, long-segment involvement, asymmetry, indistinct outer margin, luminal irregularity, hyperenhancement relative to the liver parenchyma) may favor a malignant cause. Awareness of the various causes of bile duct strictures in adults and familiarity with their appearances at MR imaging-MR cholangiopancreatography are important for accurate diagnosis and optimal patient management.

Magnetic resonance cholangiography in the assessment and management of biliary complications after OLT

Despite advances in patient and graft management, biliary complications (BC) still represent a challenge both in the early and delayed period after orthotopic liver transplantation (OLT). Because of unspecific clinical presentation, imaging is often mandatory in order to diagnose BC. Among imaging modalities, magnetic resonance cholangiography (MRC) has gained widespread acceptance as a tool to represent the reconstructed biliary tree noninvasively, using both the conventional technique (based on heavily T2-weighted sequences) and contrast-enhanced MRC (based on the acquisition of T1-weighted sequences after the administration of hepatobiliary contrast agents). On this basis, MRC is generally indicated to: (1) avoid unnecessary procedures of direct cholangiography in patients with a negative examination and/or identify alternative complications; and (2) provide a road map for interventional procedures or surgery. As illustrated in the review, MRC is accurate in the diagnosis of different types of biliary complications, including anastomotic strictures, non-anastomotic strictures, leakage and stones.

Biliary complications following liver transplantation

Biliary tract complications are the most common complications after liver transplantation. These complications are encountered more commonly as a result of increased number of liver transplantations and the prolonged survival of transplant patients. Biliary complications remain a major source of morbidity in liver transplant patients, with an incidence of 5%-32%. Post liver transplantation biliary complications include strictures (anastomotic and non-anastomotic), leaks, stones, sphincter of Oddi dysfunction, and recurrence of primary biliary disease such as primary sclerosing cholangitis and primary biliary cirrhosis. The risk of occurrence of a specific biliary complication is related to the type of biliary reconstruction performed at the time of liver transplantation. In this article we seek to review the major biliary complications and their relation to the type of biliary reconstruction performed at the time of liver tranplantation.

Advances in endoscopic management of biliary tract complications after liver transplantation

Biliary tract complications after liver transplantation (LT) most commonly include biliary leaks, strictures, and stone disease. Living donor recipients and donation after cardiac death recipients are at an increased risk of developing biliary complications. Biliary leaks usually occur early after transplantation, whereas strictures and stone disease occur later. The diagnosis of biliary complications relies on a combination of clinical presentation, laboratory abnormalities, and imaging modalities. Biliary leaks are usually diagnosed on the basis of bilious output from a surgical drain, fluid collections on imaging, or a cholescintigraphy scan demonstrating a leak. Magnetic resonance cholangiopancreatography (MRCP) is noninvasive, does not require the administration of an intravenous contrast agent, and provides detailed imaging of the entire biliary system both above and below the anastomosis. The latter not only helps in the diagnosis of biliary strictures and stones before patients undergo invasive procedures such as endoscopic retrograde cholangiopancreatography (ERCP) but also allows treating physicians to plan the optimal treatment approach. MRCP has, therefore, replaced invasive therapeutic modalities such as ERCP as the modality of choice for the diagnosis of biliary strictures and stones. There have been significant advances in endoscopic accessories, including biliary catheters, wires, and stents, as well as endoscopic technologies such as overtube-assisted endoscopy over the last decade. These developments have resulted in almost all patients, including those with difficult strictures or altered surgical anatomies (eg, Roux-en-Y hepaticojejunostomy), being treated via an endoscopic approach with percutaneous transhepatic cholangiography, which is more invasive and associated with significant morbidity, with surgery being reserved for a small minority of patients. Advances in the diagnosis and endoscopic management of patients with biliary complications after LT are discussed in this review.

Degree of bile-duct dilatation in liver-transplanted patients with biliary stricture: a magnetic resonance cholangiography-based study

PURPOSE

This study assessed whether the degree of bile-duct dilatation in liver-transplanted patients is correlated with the time from intervention and the type of underlying biliary stricture.

METHODS AND MATERIALS

Fifty-seven 3D magnetic resonance cholangiograms (MRCs) performed on 42 liver-transplanted patients were retrospectively evaluated. Diameter was measured at the level of the extrahepatic bile duct (EBD), right hepatic duct (RHD), left hepatic duct (LHD), anterior and posterior right hepatic ducts (aRHD, pRHD) and left lateral and medial ducts (LLD, LMD). Data were stratified according to the type of biliary stricture (all types, anastomotic, ischaemic-like, mixed) and compared, on a per-examination basis: (a) between two groups based on time from transplantation using a 1-year threshold (nonlongitudinal analysis); (b) among 26 repeated examinations on 11 patients (longitudinal analysis); (c) among different stricture groups.

RESULTS

The biliary tree was slightly dilated within 1 year from transplantation (2.9±1.3 to 6.1±3.2 mm). In general, nonlongitudinal analysis showed minimally larger duct size after 1 year (mean +1.4±0.5 mm) despite significant differences at most sites of measurement considering all types of strictures (p<0.01; Mann-Whitney U test). Longitudinal analysis showed diameter increase over time, although without statistically significant differences (p>0.01; Kruskal-Wallis test). No significant difference in bile-duct size was observed when comparing types of stricture (p>0.01; Kruskal-Wallis test).

CONCLUSIONS

Biliary dilatation after liver transplantation is mild and develops slowly regardless of the underlying type of stricture, possibly in relation to graft properties. MRC has a potential role as first-line imaging modality for a reliable assessment of biliary dilatation and the presence of a stricture.

Role of magnetic resonance imaging in the detection of anastomotic biliary strictures after liver transplantation

INTRODUCTION

Biliary complications after orthotopic liver transplantation (OLT) are the principal cause of morbidity and graft dysfunction, ranging in incidence from 5.8% to 30% of cases. Biliary strictures are the most frequent type of late complication. The aim of this study was to evaluate the role of magnetic resonance cholangiography (MRC) to detect biliary anastomotic strictures among patients undergone OLT with abnormal liver function tests.

MATERIALS AND METHODS

One hundred twenty-one of 300 patients who underwent OLT were evaluated by MRC for clinically suspected anastomotic biliary strictures. In all patients, we performed various precholangiographic sequences including T1- and T2-weighted and MRC (radial SE 2D and SS-TSE 3D). Magnetic resonance imaging findings were subdivided as absence or presence of an anastomotic stricture. Diagnostic confirmation was obtained by endoscopic retrograde cholangiography (n=32), percutaneous transhepatic cholangiography (n=21) or surgical treatment (n=18).

RESULTS

MRC detected 56 anastomotic biliary strictures, 53 of which were confirmed by other imaging modalities. MRC showed two false-negative cases and three false-positive cases. The sensitivity, specificity, positive and negative predictive values, and accuracy of MRC to detect biliary strictures were 96%, 96%, 95%, 97%, and 96%, respectively.

CONCLUSION

MRC proved to be a reliable noninvasive technique to visualize the biliary anastomosis and depict biliary strictures after OLT. MRC should be used when a biliary anastomotic stricture is suspected in an OLT patient.

The role of ultrasound and magnetic resonance cholangiopancreatography for the diagnosis of biliary stricture after liver transplantation

PURPOSE

To identify the diagnostic value of ultrasound (US) and magnetic resonance cholangiopancreatography (MRCP) in diagnosing biliary strictures after liver transplantation.

MATERIALS AND METHODS

Sixty patients with clinically suspected biliary strictures after liver transplantation were retrospectively evaluated. All patients underwent US and MRCP before the standard of reference (SOR) procedure: endoscopic retrograde cholangiopancreatography or percutaneous transhepatic cholangiography. Radiological images were analyzed for biliary dilatation and strictures.

RESULTS

By SOR, biliary dilatation was present in 55 patients, stricture in 53 (44 anastomotic, 4 intrahepatic, 5 both), and dilatation and/or stricture in 58. Dilatation was diagnosed by US and MRCP in 39 and 45, respectively (sensitivity 71% vs. 82%, p=0.18). Stricture was diagnosed by US and MRCP in 0 and 42, respectively (sensitivity 0% vs. 79%, p<0.0001). False positive stricture was diagnosed by MRCP in 2. Dilatation and/or stricture was diagnosed by US in 39 and MRCP in 50 (sensitivity 67% vs. 86%, p=0.01); however, using both techniques, sensitivity increased to 95%.

CONCLUSIONS

MRCP is superior to US for diagnosing biliary strictures after liver transplantation primarily because MRCP can detect stricture. The combination of US and MRCP seems superior to either method alone. Our data suggest that in patients with normal US and MRCP, direct cholangiography could be avoided.

Impact of magnetic resonance cholangiography in managing liver-transplanted patients: preliminary results of a clinical decision-making study

PURPOSE

This study was performed to assess the role of magnetic resonance cholangiography (MRC) in the clinical decision-making process of referring physicians when managing liver-transplanted patients.

MATERIALS AND METHODS

Over a 6-month period, 21 liver-transplanted patients with a suspected biliary complication were referred for MRC. Referring physicians were asked to prospectively state, before and after MRC, the leading diagnosis; the level of confidence (on a 0-100% scale); the most appropriate diagnostic/therapeutic plan. Data analysis assessed was the diagnostic yield of MRC; the proportion of change in the leading diagnosis; the therapeutic efficacy (i.e. proportion of change in the initial diagnostic/therapeutic plan); the diagnostic thinking efficacy (i.e., gain in diagnostic confidence). Statistical significance was assessed with the Mann-Whitney U test. MRC accuracy was also calculated.

RESULTS

Data analysis showed a diagnostic yield of 85.7%; a proportion of change in leading diagnosis of 19.0%; a therapeutic efficacy of 42.8%; a diagnostic thinking efficacy for concordant and discordant leading diagnoses of 18.8% and 78.7%, respectively (p<0.01). MRC accuracy was 92.3%.

CONCLUSIONS

MRC significantly increased the diagnostic confidence, irrespective of the concordance between pre- and posttest diagnoses. Moreover, MRC determined a change in patient management in a significant proportion of cases, leading to clinical benefits.

Is MRCP equivalent to ERCP for diagnosing biliary obstruction in orthotopic liver transplant recipients? A meta-analysis

BACKGROUND

Biliary complications are the second leading cause of morbidity and mortality in orthotopic liver transplant (OLT) recipients. Endoscopic retrograde cholangiography (ERC) is considered the diagnostic criterion standard for post-orthotopic liver transplantation biliary obstruction, but incurs significant risks.

OBJECTIVE

To determine the diagnostic accuracy of MRCP for biliary obstruction in OLT patients.

DESIGN

A systematic literature search identified studies primarily examining the utility of MRCP in detecting post-orthotopic liver transplantation biliary obstruction. A meta-analysis was then performed according to the Quality of Reporting Meta-Analyses statement.

SETTING

Meta-analysis of 9 studies originally performed at major transplantation centers.

PATIENTS

A total of 382 OLT patients with clinical suspicion of biliary obstruction.

INTERVENTIONS

MRCP and ERCP or clinical follow-up.

MAIN OUTCOME MEASUREMENTS

Sensitivity and specificity of MRCP for diagnosis of biliary obstruction.

RESULTS

The composite sensitivity and specificity were 0.96 (95% CI, 0.92-0.98) and 0.94 (95% CI, 0.90-0.97), respectively. The positive and negative likelihood ratios were 17 (95% CI, 9.4-29.6) and 0.04 (95% CI, 0.02-0.08), respectively.

LIMITATIONS

All but 1 included study had significant design flaws that may have falsely increased the reported diagnostic accuracy.

CONCLUSIONS

The high sensitivity and specificity demonstrated in this meta-analysis suggest that MRCP is a promising test for diagnosing biliary obstruction in patients who have undergone liver transplantation. However, given the significant design flaws in most of the component studies, additional high-quality data are necessary before unequivocally recommending MRCP in this setting.

Biliary complications following liver transplantation

The aphorism that reconstruction of the biliary anastomosis is the "Achilles heel" of liver transplantation remains valid as biliary complications following liver transplantation remain a major source of morbidity with an incidence of 5-32%. Biliary complications include biliary strictures, biliary leaks, and stones. Biliary strictures can be divided into anastomotic and non-anastomotic. The management of biliary complications previously relied on surgical intervention. However, advances in endoscopic and radiological interventions have resulted in less-invasive options. The management of biliary complications post-liver transplantation requires a multidisciplinary approach and continues to evolve. Biliary complications also reflect the continued expansion of the donor pool with extended, live, and non-heart beating donors.

Biliary tract complications after liver transplantation

Biliary tract complications are an important source of morbidity after liver transplantation, and present a challenge to all involved in their care. With increasing options for transplantation, including living donor and split liver transplants, the complexity of these problems is increasing. However, diagnosis is greatly facilitated by modern noninvasive imaging techniques. A team approach, including transplant hepatology and surgery, interventional endoscopy and interventional radiology, results in effective solutions in most cases, such that operative reintervention or retransplantation is rarely required.

Interventional radiology procedures in adult patients who underwent liver transplantation

Interventional radiology has acquired a key role in every liver transplantation (LT) program by treating the majority of vascular and non-vascular post-transplant complications, improving graft and patient survival and avoiding, in the majority of cases, surgical revision and/or re-transplantation. The aim of this paper is to review indications, technical consideration, results achievable and potential complications of interventional radiology procedures after deceased donor LT and living related adult LT.

Management of biliary complications after orthotopic liver transplantation: The role of endoscopy

Biliary complications are significant causes of morbidity and mortality after orthotopic liver transplantation (OLT). The estimated incidence of biliary complications after OLT ranges between 10%-25%, however, these numbers continue to decline due to improvement in surgical techniques. The most common biliary complications are strictures (both anastomotic and non-anastomotic) and bile leaks. Most of these problems can be appropriately managed with endoscopic retrograde cholangiography (ERC). Other complications such as bile duct stones, bile casts, sphincter of Oddi dysfunction, and hemobilia, are less frequent and also can be managed with ERC. This article will review the risk factors, diagnosis, and endoscopic management of the most common biliary complications after OLT.