The value of magnetic resonance cholangiography in the preoperative assessment of living liver donors

Association between anatomic variations of extrahepatic and intrahepatic bile ducts: Do look up!

Biliary anatomic variations are usually asymptomatic, but they may cause problems in diagnostic investigations and interventional and surgical procedures, increasing both their technical difficulty and their postoperative complication rates. The aim of the present study was to evaluate the prevalence of anatomic variations in the intrahepatic biliary ducts (IHBD) in relation to demographical and clinical characteristics in a large study population requiring magnetic resonance cholangiopancreatography (MRCP) for various clinical conditions. The possible association between IHBD and extrahepatic biliary ducts (EHBD) variants was then explored. From January 2017 to May 2019, 1004 patients underwent MRCP. Demographical and clinical data were collected. IHBD and EHBD anatomy were recorded and the EHBD anatomy was classified using both qualitative and quantitative classifications. The presence of a type 3 EHBD variant (an abnormal proximal cystic duct [CD] insertion) in both qualitative and quantitative classifications and an intrapancreatic CD were associated with the presence of IHBD variants at univariate analysis (p = 0.008, p = 0.019, and p = 0.001, respectively). The presence of a posterior or medial insertion of the CD into the EHBD was a strong predictive factor of the presence of IHBD variants both at uni- and multivariate analysis (p = 0.002 and p = 0.003 for posterior insertion and p = 0.002 and p = 0.002 for medial insertion, respectively). The presence of gallstones on MRCP resulted in a strong predictor of the presence of an anatomical variant of the IHBD both at uni- and multivariate analysis (p = 0.027 and p = 0.046, respectively). In conclusion, the presence of a type 3 variant of the EHBD, an intrapancreatic CD and, especially, a posterior/medial CD insertion into the EHBD represent predictive factors of the concomitant presence of IHBD variants, thus radiologists must be vigilant when encountering these EHBD configurations and always remember to "look up" at the IHBD. Finally, the presence of an IHBD variant is a strong predictive factor of gallstones.

Anatomic variations of the intra-hepatic biliary tree in the Caribbean: A systematic review

BACKGROUND

In the classic descriptions of the human liver, the common hepatic duct forms at the confluence of left and right hepatic ducts. Many authors have documented variations in the intra-hepatic ductal system, but to the best of our knowledge there has been no report on bile duct variations in Caribbean populations.

AIM

To evaluate the variations in bile duct anatomy using magnetic resonance cholangiography (MRC) in unselected patients at a major hepatobiliary referral centre in the Eastern Caribbean. Knowledge of the intra-hepatic biliary anatomy is important to optimize service delivery for any physician treating liver and biliary disorders.

METHODS

This study was carried out at a tertiary referral hospital for hepatobiliary diseases in the Eastern Caribbean. We retrospectively evaluated magnetic resonance cholangiograms in 152 consecutive patients at this facility over a two-year period from April 1, 2017 to March 31, 2019. Two consultant radiologists experienced in MRC interpretation reviewed all scans and described biliary anatomy according to the Huang’s classification. A systematic review of published studies was performed and relevant data were extracted in order to calculate the global prevalence of each biliary variant. The variants in our population were compared to the global population.

RESULTS

There were 152 MRCs evaluated in this study in 86 males and 66 females. There were 109 (71.7%) persons with “classic” biliary anatomy (type A1) and variants were present in 43 (28.3%) persons. There was no statistical relationship between the presence of anatomic variants and gender or ethnicity. We encountered the following variants: 29 (19.1%) type A2, 7 (4.6%) type A3, 6 (3.95%) type A4, 0 type A5 and a single variant (quadrification) that did not fit the classification system. Compared to the global prevalence, our population had a significantly greater occurrence of A1 anatomy (71.7% vs 62.6%; P = 0.0227) and A2 trifurcations (19.1% vs 11.5%; P = 0.0069), but a significantly lower incidence of A3 variants (4.61% vs 11.5%; P = 0.0047).

CONCLUSION

There are significant differences in intra-hepatic biliary anatomy in this unselected Eastern Caribbean population compared to global statistics. Specifically, persons of Caribbean descent have a greater incidence of Huang A2 trifurcations and a lower incidence of Huang A3 variants.

Comprehensive classification of anatomical variants of the main biliary ducts

This systematic review provides the most comprehensive overview of intrahepatic biliary anatomical variants to date. Additionally, it proposes a clinically focused, prevalence-based classification system based on meta-analysis of a large pooled dataset whilst incorporating the merits of previous classification systems.

Correlation Among 3-Dimensional Magnetic Resonance Cholangiography, Intraoperative Cholangiography, and Intraoperative Findings in Right Liver Donors

OBJECTIVES

A correct preoperative definition of the hepatic duct confluence anatomy of right liver living donors is pivotal in determining their candidacy for donation and planning surgery during liver transplant. Here, we evaluated the accuracy of 3-dimensional magnetic resonance cholangiography compared with intraoperative cholangiography in assessing biliary anatomy and aimed to identify imaging characteristics that may help to predict the yield of hepatic duct orifices in the right liver graft.

MATERIALS AND METHODS

All consecutive living hepa-tectomy donors for adult liver transplant included in this study (N = 110) were evaluated with preoperative 3-dimensional magnetic resonance cholangiography, which was performed before and after intravenous administration of gadolinium (20-40 cm³). For intraoperative cholangiography, a 4F catheter was advanced through the cystic duct, and contrast matter (5-10 mL) was injected into the biliary tree via the catheter. The number of right hepatic ducts in explanted graft was determined on the back table.

RESULTS

Of 110 donors, 71 had type 1 (normal) biliary anatomy based on both 3-dimensional magnetic resonance and intraoperative cholangiography and 39 had abnormal biliary anatomy, with 2 having type 3 (abnormal) biliary anatomy. Normal biliary anatomy was found in back-table examination, and abnormal biliary anatomy (type 2) was found with intraoperative cholangiography. Sensitivity, specificity, and predic-tive values of 3-dimensional magnetic resonance cholangiography in revealing the biliary anatomy and anomalies were compared with intraoperative cholangiography findings. Observed final hepatic duct outcomes were also assessed. Use of 3-dimensional magnetic resonance cholangiography accurately predicted the biliary anatomy in 97 of 110 cases. Sensitivity was 80.4%, positive predictive value was 94.4%, specificity was 96.9%, and negative predictive value was 87.3%.

CONCLUSIONS

Three-dimensional magnetic resonance cholangiography reliably represented normal biliary anatomy; the presence of anatomic variations decreased its sensitivity, making intraoperative cholangiography or duct probing necessary tools to accurately perform right hepatic duct transection.

Comparison Between Pre-operative Radiologic Findings and the Actual Operative Findings of the Graft in Adult Living Donor Liver Transplantation

BACKGROUND

Computed tomography (CT) volumetry and magnetic resonance cholangiopancreatography (MRCP) are mandatory steps for the evaluation of potential donors in living donor liver transplantation. The aim of this study is to compare the preoperative CT volumetry and biliary orifices of the donor graft to the actual operative findings.

METHODS

Between December 2013 and December 2017, 45 donors (27 men and 18 women) with a mean age of 27.3 years (range, 19-41 years) were evaluated preoperatively by CT volumetry and MRCP at the National Hepatology and Tropical Medicine Research Institute in Cairo, Egypt. Of the donors, 43 out of 45 underwent intraoperative cholangiography before and after bile duct division. The right hepatectomies for all donors, as well as the actual weight and apparent biliary orifices in the graft, were documented.

RESULTS

The mean estimated graft volume (EGV) preoperatively by CT volumetry was 894.9 ± 184.2 mL (range, 480-1687 mL), whereas the actual graft weight (AGW) intraoperatively after washout was 862.6 ± 124.4 g (range, 676-1110 g). The correlation coefficient between the EGV and AGW was significantly linear (Y = 0.96X, r² = 0.72, slope: 0.96, P < .001). The accuracy of the MRCP in preoperative biliary mapping was 76.7% whereas the accuracy of the MRCP in predicting the number of graft biliary orifices was 74.4% compared with the intraoperative cholangiography (IOC), which was 95.3% (P < .001).

CONCLUSION

The weight of the right lobe of the liver graft in living donor liver transplants (LDLTs) can be accurately predicted preoperatively by multiplying the EGV by 0.96. Also, the IOC is an essential technique for LDLT.

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.

Magnetic resonance cholangiography in assessing biliary anatomy in living donors: A meta-analysis

AIM: To establish the role of magnetic resonance cholangiography (MRC) in diagnosis of biliary anatomy in living-donor liver transplantation (LDLT) donors.

METHODS: A systematic review was performed by searching electronic bibliographic databases prior to March 2013. Studies with diagnostic results and fulfilled inclusion criteria were included. The methodological quality of the studies was assessed. Sensitivity, specificity and other measures of the accuracy of MRC for diagnosis of biliary anatomy in LDLT donors were summarized using a random-effects model or a fixed-effects model. Summary receiver operating characteristic (SROC) curves were used to summarize overall test performance. Publication bias was assessed using Deek’s funnel plot asymmetry test. Sensitivity analysis was adopted to explore the potential sources of heterogeneity.

RESULTS: Twelve studies involving 869 subjects were eligible to the analysis. The scores of Quality Assessment of Diagnostic Accuracy Studies for the included studies ranged from 11 to 14. The summary estimates of sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, diagnostic OR of MRC in diagnosis of biliary anatomy in LDLT donor were 0.88 (95%CI: 0.84-0.92), 0.95 (95%CI: 0.93-0.97), 15.33 (95%CI: 10.70-21.95), 0.15 (95%CI: 0.11-0.20) and 130.77 (95%CI: 75.91-225.27), respectively. No significant heterogeneity was detected in all the above four measures. Area under SROC curve was 0.971. Little publication bias was noted across the studies (P = 0.557). Sensitivity analysis excluding a study with possible heterogeneity got a similar overall result, which suggested the little influence of this study on the overall results.

CONCLUSION: Our results suggest that MRC is a high specificity but moderate sensitivity technique in diagnosis of biliary anatomy in LDLT donors.

Biliary and vascular anomalies in living liver donors: the role and accuracy of pre-operative radiological mapping

BACKGROUND

The aim of the present study was to determine the utility of computed tomography (CT) and magnetic resonance imaging (MRI) anatomic mapping in the detection of biliary and vascular anomalies prior to a living liver donor (LLD) operation.

METHODS

A retrospective study of all LLD patient charts, operative and radiology reports from 1 January 2002 to 1 January 2012 was conducted. Primary post-operative outcomes assessed included mortality, re-operation, readmission and need for endoscopic or percutaneous intervention. Sensitivity and specificity of MR and CT pre-operative screening was calculated against the gold standard of intra-operative findings.

RESULTS

A total of 34 donors had an average age of 38 years (range: 22-58) with a body mass index (BMI) of 25.6 kg/m(2) (range: 19.8-32.5) and a length of stay (LOS) of 10.1 days (range: 5-41). There were no donor mortalities. Sensitivity and specificity of CT was 70.0% and 91.3%, and of MRI screening 23.1% and 100.0%, respectively. Patients with inaccurate pre-operative CT or MRI did not have an increased risk of complications.

CONCLUSIONS

Even although it was specific, pre-operative MR screening missed up to 77.0% of biliary anomalies. An impeccable surgical technique remains the key in preventing biliary complications of a living donor hepatectomy where pre-operative MRI screening is false.

Use of pineapple juice with gadopentetate dimeglumine as a negative oral contrast for magnetic resonance cholangiopancreatography: a multicentric study

We evaluated the efficacy of pineapple juice with gadopentetate dimeglumine as a negative oral contrast agent for magnetic resonance cholangiopancreatography (MRCP). Images were obtained before and after the intake of a negative oral contrast agent. Images obtained from six different areas of the biliary tree were analyzed by three different radiologists, who were blind to the exams; scores regarding image quality were given to each area. The statistical analysis showed a significant difference between images before and after the use of the contrast agent (P < 0.001) for the three radiologists (R1-R3). Mean scores given by radiologists before the intake of the contrast agent were 2.49 ± 0.42 (R1), 2.62 ± 0.32 (R2), and 2.22 ± 0.46 (R3). After the intake, mean scores were 3.38 ± 0.62 (R1), 3.48 ± 0.55 (R2), and 2.89 ± 0.69 (R3). The ducts that showed the highest scores were the common bile duct and duct of Wirsung, the distal portion of the common bile duct and the cystic duct. We suggest herein that the contrast agent pineapple juice with gadopentate dimeglumine constitutes an efficient negative oral contrast agent for MRCP, for it efficiently eliminates the signal of the digestive tube in MRCP images.

Anatomic variations of intrahepatic bile ducts in a European series and meta-analysis of the literature

BACKGROUND

Accurate knowledge of biliary anatomy and its variants is essential to ensure successful hepatic surgery; however, data from European countries are lacking.

METHODS

Two hundred cholangiograms obtained from patients submitted to whole liver transplantation were reviewed; donors' characteristics were related to the prevalence of typical biliary anatomy and its variants. A comprehensive literature search was performed with MEDLINE and EMBASE from 1980 to 2010 to investigate whether geographical origin could be related to biliary abnormalities.

RESULTS

Typical biliary anatomy was observed in 64.5% of cases, but female donors more frequently presented an anatomic variation; typical anatomy was present in 55.0% of females and in 74.0% of males (P = 0.005). Twenty-two reports were identified by the literature search with a total of 7,559 cases, including the present series; heterogeneity was low (Q = 14.60; I2 < 5.0%) after exclusion of three outlier reports. Prevalence of typical biliary anatomy was similar in Europeans and Americans (∼60%); a slightly higher prevalence was observed in Asiatics (∼65%).

CONCLUSIONS

Anatomic variants seem to be more frequent in females, probably as a consequence of different embryologic development. Available data suggest that typical biliary anatomy can be more frequent in Asiatics, but an accurate means of classification is essential to making comparison realistic.

Imaging in liver transplantation

The aim of this study was to illustrate the role of non-invasive imaging tools such as ultrasonography, multi-detector row computed tomography, and magnetic resonance imaging in the evaluation of pediatric and adult liver recipients and potential liver donors, and in the detection of potential complications arising from liver transplantation.