Types and frequencies of biliary tract variations associated with a major portal venous anomaly: analysis with multi-detector row CT cholangiography

Identification and verification of communicating accessory bile duct associated with a biliary circuit by modified and dynamic intraoperative cholangiography during laparoscopic cholecystectomy

Communicating accessory bile duct (CABD) is a rare anatomical anomaly of the bile duct and forms a biliary circuit. It is difficult to identify during laparoscopic cholecystectomy (LC) without the use of intraoperative cholangiography (IOC). A modified IOC, in which tube insertion was performed through the infundibulum of the gallbladder, was evaluated dynamically. This procedure allowed us to accurately identify and verify the presence of CABD, a biliary circuit, and the short cystic duct. The short cystic duct could be separated safely without damaging the biliary circuit. Modified and dynamic IOC is recommended for identifying and verifying the presence of CABD during LC.

Surgery

This chapter provides a comprehensive background from basic to applied knowledge of surgical anatomy which is necessary for the surgical treatment of cholangiocarcinoma (CCA) patients. Significant advances that have been made in the surgical treatment of CCA were examined. For instance, in-depth details are provided for appropriate preoperative assessment and treatment to optimize patient status and to improve the outcome of surgical treatment(s). Comprehensive details are provided for the surgical techniques and outcomes of treatments for each type of CCA with clear illustrations and images. This chapter also describes the role of minimally invasive surgery and liver transplantation in CCA treatment.

Modified and dynamic intraoperativecholangiography during laparoscopic cholecystectomy in two patients with aberrant right posterior hepatic duct

Aberrant right posterior hepatic duct (ARPHD) is one of the anatomical anomalies of the bile duct. It is a risk factor for bile duct injury during laparoscopic cholecystectomy (LC). ARPHD can be diagnosed before surgery by magnetic resonance cholangiopancreatography or drip infusion cholangiographic-computed tomography. However, it is not easy to identify ARPHD during LC. Classic intraoperative cholangiography (IOC) procedure that does not lead to bile duct injury avoidance needs to be modified. In modified IOC, cannulation is performed from the infundibulum or neck of the gallbladder. We reported a modified and dynamic IOC procedure that can identify ARPHD safely and precisely during LC. The modified IOC provided direct evidence of no injury to ARPHD in 2 cases.

Type Va Duplication of the Common Bile Duct With Type IIIa Intrahepatic Bile Duct Anatomy: A Rare Combination of Dual Biliary Ductal Anomaly With Difficulty to Extract Common Bile Duct Stone

Extrahepatic duplication of the common bile duct (CBD) is an extremely rare anatomic variation seen in the biliary tract. It represents failure of regression of the primitive duplicated biliary ductal system, resulting in five different subtypes of the duplicated CBD as described by Choi et al. To date, only few such cases have been reported in the literature. Associated variation in branching of intrahepatic bile ducts presenting as combined dual ductal anomaly is even rarer phenomena to be seen. We report a case of a 67-year-old man with chronic kidney disease and obstructive jaundice resulting from choledocholithiasis. Evaluation revealed type IIIa branching of intrahepatic bile ducts with type Va duplication of the CBD.

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.

Anatomic variations of the extrahepatic biliary tree. A monocentric study and review of the literature

INTRODUCTION

The study of the anatomy of the extra hepatic bile ducts has demonstrated the existence of a significant number of variants which can be explained by hepato-biliary embryology. A good knowledge of this anatomy is essential for the interpretation of radiological examinations, and for a good practice of hepato-biliary and pancreatic surgery. Several imaging methods are used to study the anatomy of the bile ducts, including classical cholangiography, which is still practiced and very useful.

AIM

To study the modal anatomy (the most frequent) and the anatomical variants of the extrahepatic bile ducts through the interpretation of postoperative cholangiograms and to examine their implication on the surgical practice.

METHODS

This is a monocentric, retrospective observational study. It concerned any patient who underwent hepato-biliary or pancreatic surgery at the Department of General and Digestive Surgery of Farhat Hached University Hospital of Sousse between 2007 and 2016, and who received postoperative cholangiography. A data form was fulfilled for each patient.

RESULTS

Out of a total population of 293 patients, we identified 158 patients (53.9%) with anatomic variants of the extrahepatic bile ducts. The common bile duct was modally implanted in the second duodenum in 96.2% of cholangiographies and in the genu inferius in 3.8% of cases. The main pancreatic duct had a V-shaped implantation in 87.1% of cholangiograms, a U-shaped implantation in 4.2% of cases and a Y-shaped implantation in 7.1% of cases. The common bile duct had a modal aspect in 71.3% of cholangiograms, with 28.7% of anatomic variants, organized in 4 models. The cystic duct had a modal presentation in 80.9% of cases, and we recorded 6 other branching models (19.1% of cases). No significant difference was observed between the presence of anatomic variants on the one hand, and age, sex, conversion rate, intraoperative incidents, postoperative complications, postoperative hospital stay and overall hospital stay on the other hand.

CONCLUSION

Conventional cholangiography constitutes a more or less precise tool for detecting these anatomic variants and is therefore very useful in the practice of hepato-biliary surgery even after the advent of new techniques in this field. However, it also requires a more extensive and in-depth knowledge of these anatomic variants, which nevertheless remain quite frequent, and represent a source of surgical difficulties.

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.

CT and MR imaging evaluation of living liver donors

Preoperative cross-sectional imaging evaluation of potential living liver donors allows to exclude donors with an increased risk for morbidity and mortality, and to assure that a suitable graft for the recipient can be obtained, minimizing the risk of complications in both the donor and the recipient. CT is routinely performed to delineate the anatomy of the liver, relevant vasculature, and liver volumes in whole right or left lateral segment donation. MR imaging is the gold standard for the assessment of biliary anatomy and allows a better quantification of hepatic steatosis compared to CT. Knowledge of normal and variant vascular and biliary anatomy and their surgical relevance for liver transplantation is of paramount importance for the radiologist. The purpose of this review is to outline the current role of CT and MR imaging in the assessment of hepatic parenchyma, hepatic vascular anatomy, biliary anatomy, and hepatic volumetry in the potential living liver donor with short notes on acquisition protocols and the relevant reportable findings.

Deep learning reconstruction of drip-infusion cholangiography acquired with ultra-high-resolution computed tomography

PURPOSE

Deep learning reconstruction (DLR) introduces deep convolutional neural networks into the reconstruction flow. We examined the clinical applicability of drip-infusion cholangiography (DIC) acquired on an ultra-high-resolution CT (U-HRCT) scanner reconstructed with DLR in comparison to hybrid and model-based iterative reconstruction (hybrid-IR, MBIR).

METHODS

This retrospective, single-institution study included 30 patients seen between January 2018 and November 2019. A radiologist recorded the standard deviation of attenuation in the paraspinal muscle as the image noise and calculated the contrast-to-noise ratio (CNR) in the common bile duct. The overall visual image quality of the bile duct on thick-slab maximum intensity projections was assessed by two other radiologists and graded on a 5-point confidence scale ranging from 1 (not delineated) to 5 (clearly delineated). The difference among hybrid-IR, MBIR, and DLR images was compared.

RESULTS

The image noise was significantly lower on DLR than hybrid-IR and MBIR images and the CNR and the overall visual image quality of the bile duct were significantly higher on DLR than on hybrid-IR and MBIR images (all: p < 0.001).

CONCLUSION

DLR resulted in significant quantitative and qualitative improvement of DIC acquired with U-HRCT.

Biliary anatomy and pancreatic duct variations: A cross-sectional study

BACKGROUND/AIM

Biliary tree and pancreatic duct can appear in different variations whose proper understanding is obligatory for surgeons. Magnetic resonance cholangiopancreatography (MRCP) is considered a safe and accurate tool for evaluating biliary tree and pancreatic duct. Typical anatomy for right hepatic duct (RHD) and left hepatic duct (LHD) is reported as 57% and 63%, respectively. The most common (4-10%) pancreatic anomaly is divisum. In the present study, we evaluated and determined the prevalence of biliary tree and pancreatic duct variations among patients at a university hospital.

MATERIALS AND METHODS

The MRCP records of 370 patients from 2015 to 2017 were obtained for cross-sectional study. Images were retrospectively reviewed for variations by two independent senior radiologists. Demographic data were obtained for all the patients. Huang et al. classification was used for RHD and LHD variations. The cystic duct was reported based on its course and insertion pattern. The pancreatic duct was observed for the presence of divisum, its course, and configuration.

RESULTS

Three hundred and twenty-five patients were included in the final study. Most commonly observed variant for RHD were A1 (34.2%) and A2 (32.2%). For LHD, B1 (71.4%) was the most common variant. Cystic duct insertion was commonly seen as right lateral insertion (27.7%). Pancreatic divisum was observed in 0.6% of cases. Nationality, origin, and gender-specific variations were obtained.

CONCLUSION

Variations in biliary anatomy and pancreatic duct are very diverse and extend from the intrahepatic biliary system down to the pancreas. Performing a similar study on a larger population is mandatory to illustrate the range of variations present within the community.

Intrahepatic bile duct variation: MR cholangiography and implication in hepatobiliary surgery

Background

The aim of this study was to assess the prevalence of biliary anatomical variants using 3-T MR cholangiography (MRC) with its impact in reduction of the complication of hepatobiliary surgical techniques.

Results

MRC was applied to 120 subjects (24 potential liver donors and 96 volunteers) and the right posterior hepatic duct insertion was documented, and accordingly, the biliary variants were classified based on Huang classification (Huang et al, Transplant Proc 28: 1669–1670, 1996).

Biliary anatomic variants were divided based on Huang classification: Huang A1, 65.83% (n = 79); Huang A2, 11.67% (n = 14); Huang A3, 13.3% (n = 16); Huang A4, 7.5% (n = 9); and Huang A5, 1.67% (n = 2). The total frequency for A2, A3, A4, and A5 was 34.17% (n = 41). The distance between RPHD insertion and the junction of right and left hepatic ducts (L) was measured, and Huang A1 cases were then subtyped into S1 subtype (L > 1 cm) and S2 subtype (L ≤ 1 cm). We had 52 subjects with subtype S1 (43.33%) and 27 subjects with subtype S2 (22.5%).

Twenty-three subjects had bile duct exploration or intraoperative cholangiograms and showed Huang type A1 in 14 (60.87%), type A2 in 3 (13.05%), and type A3 in 6 (26.08%). Twenty-two (95.65%) had the same classification in MRC and intraoperative while only one case (4.35%) was considered as A2 at MRC but the intraoperative classification was Huang A3, which was attributed to the insertion of the RPHD insertion at the distal end of the left hepatic duct.

Conclusion

MRC is an accurate tool for biliary tract mapping before hepatobiliary surgery to provide excellent identification of biliary variants which can reduce the incidence of biliary complications.

Clinical investigation of the cystic duct variation based on the anatomy of the hepatic vasculature

PURPOSE

Anatomical variation of the cystic duct (CD) is rare but can result in misunderstanding of the CD anatomy during laparoscopic cholecystectomy, potentially leading to bile duct injury. Therefore, the precise preoperative identification of CD variation is important. However, preoperative imaging analyses of the biliary system are not always possible or sufficient. We therefore investigated CD variations based on the anatomy of the hepatic vasculature.

METHODS

This study enrolled 480 patients who underwent imaging before hepatobiliary pancreatic surgery. We assessed the variation of the CD and hepatic vasculature and evaluated the correlations among these variations.

RESULTS

A variant CD anatomy was identified in 12 cases (2.5%) as CD draining into the right hepatic bile duct (BD) in 4 cases and into the right posterior BD in 8 cases. CD variation was significantly more common in cases with portal vein (PV) and BD variation than in those without the variation. We developed a scoring system based on the presence of PV and BD variations that showed good discriminatory power for identification of CD variants.

CONCLUSION

Cases with a variant CD anatomy were more likely to exhibit variant PV and BD anatomies than cases with a normal CD anatomy. These findings will be useful for the preoperative identification of CD variants.

Rare anatomic variations of the right hepatic biliary system

PURPOSE

To report rare and clinically significant anatomic variations in the biliary drainage of right hepatic lobe.

METHODS

Unique variations in the extra- and intrahepatic biliary drainage of right hepatic lobe were observed in 6 cadaveric livers during dissection on 100 formalin-fixed en bloc cadaveric livers.

RESULTS

There was presence of aberrant drainage of right segmental and sectorial ducts in four cases and of accessory right posterior sectorial duct in two cases.

CONCLUSIONS

We encountered some extensively complicated biliary drainage of right hepatic lobe, unsuccessful recognition of which can lead to serious biliary complications during hepatobiliary surgeries and biliary interventions.

Evaluation of biliary anatomy in the caudate lobe using drip infusion cholangiography-computed tomography

PURPOSE

This study aimed to retrospectively evaluate the caudate branches (CBs), which are bile ducts originating from the caudate lobe (CL), using drip infusion cholangiography with computed tomography (DIC-CT).

METHODS

The confluence patterns of CBs were evaluated in 185 adult patients undergoing DIC-CT. The following bile duct features were evaluated: (a) number of depicted CBs; (b) identification of the caudate portion from which the CBs were derived; (c) identification of the confluence site of a CB; and (d) whether there was a difference in the confluence site of the CBs depending on the position of the right posterior hepatic duct (RPHD) and the portal vein (PV).

RESULTS

DIC-CT enabled detection of a total of 640 bile ducts from the CL in 185 patients, and the total number of CBs from the Spiegel lobe (SP), the paracaval portion, and the caudate process (CP) were 347 (54.2%), 112 (17.5%), and 181 (28.2%), respectively. In the SP, over 60% of CBs joined the left hepatic duct system (LHDS). The positional relationship between the RPHD and the PV was divided into a supra-portal course (n = 168) and an infra-portal course (n = 17). The number of CBs joining the LHDS was significantly different between a supra-portal course and an infra-portal course (p = 0.0484).

CONCLUSION

CBs were depicted by DIC-CT in 98.9% of the subjects, and a detailed evaluation was possible. The number of CBs joining the LHDS was associated with the position of the RPHD and the PV.

Cholecystic Venous Anatomy: A Cadaveric Study with Implications for Portal Venous Interruption Procedure

The techniques of portal vein embolization (PVE) or ligation (PVL) have the goals of combining an induced atrophy of metastatic segments with the rapid relative compensatory hypertrophy of the postresection future liver remnant (FLR). Our study examines the anatomy of right-left hepatic lobar venous connections in the adult cadaver using corrosion cast analysis in an effort to define some of the inherent anatomical reasons why both PVL and PVE may be technically unsuccessful. Corrosion cast models of 215 cadaveric liver specimens were evaluated for hepatopetal venous blood flow, with a particular emphasis on cholecystic venous drainage patterns, including 57 cases prepared after lobar portal venous ligation. In 88.8 per cent of corrosion casts, there was a segmental venous communication between the gallbladder and all segments of the liver, except segment II. There was cystic vein drainage directly into a main lobar branch or directly into the portal vein itself in 11.2 per cent of cases. In all 57 cases, after portal lobar venous division, in situ cystic veins allowed persistent venous communication between lobes. Our cadaveric corrosion cast study has suggested that there is extensive intrahepatic cholecystic venous drainage to many segments of the liver. Perfusion from the gallbladder may potentially contribute to a limited response to procedures which interrupt the portal venous flow and could affect their capacity to induce an adequate FLR which would permit a wider hepatectomy.

Liver vascular anatomy: a refresher

To prevent and decrease procedural complications, it is important to identify variants of hepatic vascular anatomy before interventional radiologic procedures, surgery, and liver transplantation. Knowledge of the vascular variants helps in selecting patients and in exploring alternative management options. Non-invasive detailed demonstration of the hepatic vascular anatomy is possible with advanced multi-detector computed tomography (CT) and magnetic resonance (MR) imaging. The objective of this review is to provide a brief overview of clinically relevant hepatic vascular anatomy and important variants.

Internal biliary drainage for isolated posterior segmental biliary obstruction: a case report

Background

Biliary system anatomical abnormalities can be preoperatively detected on magnetic resonance imaging; therefore, some presume that the number of bile duct injuries should decline. However, once a bile duct injury occurs, repair may be difficult. There are various ways to repair bile duct injuries, but successful repair may be exceptionally difficult.

Case presentation

A 72-year-old Japanese man underwent a pancreaticoduodenectomy due to a diagnosis of middle bile duct cancer. We had a complication of an isolated posterior segmental biliary obstruction when pancreaticoduodenectomy was performed. We conducted a drip infusion cholecystocholangiography-computed tomography test to determine the positional relationship between his bile duct and elevated jejunum. To secure the bile duct we punctured the bile duct under computed tomography guidance, and the hepaticojejunal anastomosis site was visualized by inserting an endoscope. We vibrated the bile duct wall by inserting a guide wire through a puncture needle and verified the vibrations with the endoscope. We observed a partially compressed elevated jejunal wall upon guide wire insertion; therefore, we could verify a puncture needle penetration into the elevated jejunum by endoscope on insertion. We also successfully inserted an 8.5-Fr pigtail catheter into the elevated jejunum. We removed all drains after percutaneously inserting an uncovered metallic stent. Our patient’s subsequent clinical course was unremarkable. He visits our institution as an out-patient and has had no stent occlusion even after 6 months.

Conclusions

When repairing bile duct injuries, it is important to accurately determine the positional relationships between the injured bile duct and the surrounding organs.

Success and complications of percutaneous transhepatic biliary drainage are influenced by liver entry segment and level of catheter placement

PURPOSE

To examine outcomes and complications of percutaneous transhepatic biliary drainage (PTBD) performed via the right or left lobe and different entry levels (lobar, segmental, subsegmental, sub-subsegmental).

METHODS

The records of patients who underwent PTBD for obstructive jaundice from 2008 to 2015 were retrospectively reviewed. Logistic regression analysis was performed to determine factors associated with outcomes and complications based on entry side and entry level. PTBD success was defined as a total bilirubin decrease after catheter placement.

RESULTS

The data of 446 patients (mean age 68.4 years) were included. Multivariate logistic regression revealed a decrease of bilirubin level was associated with left lobe (vs. right) entry [adjusted odds ratio (aOR) = 2.657, 95% confidence interval (CI) 1.160, 6.087], external drainage (aOR = 2.908, 95% CI 1.226, 6.897), and liver volume undrained <50% (aOR = 2.623, 95% CI 1.045, 6.581). PTBD success was increased with left lobe entry (aOR = 1.853, 95% CI 1.167, 2.940) and associated with entry level (subsegmental vs. lobar, aOR = 2.992, 95% CI 1.258, 7.114; sub-subsegmental vs. lobar, aOR = 3.711, 95% CI 1.383, 9.956). Complications were significantly decreased with left lobe entry (aOR = 0.450, 95% CI 0.263, 0.769) and associated with entry level (segmental vs. lobar, aOR = 0.359, 95% CI 0.148, 0.873; subsegmental vs. lobar, aOR = 0.248, 95% CI 0.10, 0.615; sub-subsegmental vs. lobar, aOR = 0.129, 95% CI 0.041, 0.411).

CONCLUSIONS

The success and complications of PTBD vary with entry side and level.

Anatomical Variations of the Biliary Tree Found with Endoscopic Retrograde Cholagiopancreatography in a Referral Center in Southern Iran

BACKGROUND

Anatomical variations in the biliary system have been proven to be of clinical importance. Awareness of the pattern of these variations in a specific population may help to prevent and manage biliary injuries during surgical and endoscopic procedures. Knowledge of the biliary anatomy will be also of great help in planning the drainage of adequate percentage of liver parenchyma in endoscopic or radiological procedures.

METHODS

All consecutive patients undergoing endoscopic retrograde cholangiopancreatography (ERCP) from April 2013 to April 2015 at Nemazee Hospital, a referral center in the south of Iran, were included in this cross-sectional study. The patients with previous hepatic or biliary surgery, liver injury or destructive biliary disease were excluded from the study. All ERCPs were reviewed by two expert gastroenterologists in this field. The disagreed images by the two gastroenterologists were excluded. Huang classification was used for categorizing the different structural variants of the biliary tree, and the frequency of each variant was recorded.

RESULTS

Totally, 362 patients (181 men and 181 women) were included in the study. 163 patients (45%) had type A1 Huang classification (right dominant), which was the most prevalent type among our patients. 55% of them had non-right dominant anatomy. The result of the Chi-square test revealed that there was no statistically significant difference between the men and women regarding the anatomical variations (p = 0.413).

CONCLUSION

The anatomical variation in the biliary system among Iranian patients is comparable to other regions of the world. Significant proportions of our patients are non-right dominant and may need bilateral biliary drainage.

Multidetector CT in detection of troublesome posterior sectoral hepatic duct communicating with cystic duct

OBJECTIVE

To investigate whether multiple detector CT (MDCT) could detect troublesome aberrant posterior sectoral hepatic duct (PHD) communicating with cystic duct (CD).

METHODS

The most troublesome bile duct anomaly during cholecystectomy is an aberrant PHD communicating with CD. It has been suggested that an unenhanced small duct between Rouviere's sulcus and CD on MDCT could be coincident to an aberrant PHD communicating with CD. A total of 224 patients who underwent laparotomy with complete lymph node dissection in the hepatoduodenal ligament for hepatobiliary or pancreatic tumour were enrolled. Retrospective review of preoperative MDCT images and surgical records was performed.

RESULTS

Preoperative MDCT detected 8 (3.6%) unenhanced ducts between Rouviere's sulcus and CD. Surgical records identified 7 (3.1%) cases of aberrant PHD communicating with CD, and all 7 cases showed an unenhanced duct between Rouviere's sulcus and CD on preoperative MDCT imaging. Among the 7 patients, 5 (71%) were without bile duct dilatation.

CONCLUSION

MDCT could detect troublesome aberrant PHD communicating with CD, regardless of the presence or absence of bile duct dilatation. Advances in knowledge: MDCT could detect most troublesome PHD communicating with CD, regardless of the presence or absence of bile duct dilatation.

Usefulness of 3D balanced turbo-field-echo MR sequence evaluating the branching pattern of the intrahepatic bile ducts: comparison with drip infusion CT cholangiography

PURPOSE

For liver surgery, it is crucial to preoperatively examine the course of the right posterior bile duct. While MR cholangiopancreatography (MRCP) can only visualize the bile ducts, 3D balanced turbo-field-echo (BTFE) sequence clearly depicts the bile ducts and portal veins as well as drip infusion CT cholangiography (DIC-CT), without contrast media. We evaluated whether BTFE could substitute for DIC-CT.

MATERIALS AND METHODS

Thirty patients undergoing MRCP and BTFE on 1.5-T MR and DIC-CT were evaluated. Two readers retrospectively evaluated the branching pattern (supra-type: A-C or infra-type: D-E) and scored the degree of confidence and motion artifacts using a 3-point scale for the three 2-mm-thick reconstructed images.

RESULTS

The bile duct diameter did not differ between DIC-CT and MRCP (p = 0.07). Five patients (17%) had intrahepatic biliary dilatation (>3 mm). The A, B, C, D, and E types were diagnosed in 21, 6, 1, 1, and 1 patient, respectively (28 supra-types and 2 infra-types) on DIC-CT. For DIC-CT, MRCP, and BTFE, the mean motion artifact scores were 3.0/3.0, 2.7/2.6, and 2.9/2.8, respectively. The mean diagnostic confidence scores were 2.9/2.9, 2.4/2.4, and 2.9/2.8, respectively, with no difference between DIC-CT and BTFE. The concordance between DIC-CT and BTFE was high (infra- or supra-type: κ = 1.00/1.00, A-E: κ = 0.86/0.66), but it was poor between DIC-CT and MRCP (infra- or supra-type: κ = 0.35/-0.05, A-E: κ = 0.33/0.41) for both readers.

CONCLUSIONS

Similar to DIC-CT, the BTFE MR sequence had high diagnostic accuracy regarding the branching pattern of the intrahepatic bile duct, especially for the supra/infraportal type.

Presence of Aberrant Anatomy Is an Independent Predictor of Bile Duct Injury During Cholecystectomy

The aim of this study is to investigate the impact of an aberrant anatomy diagnosed with MR cholangiography on the occurrence of bile duct injury. Although many authors report that aberrant anatomy is a strong risk factor for the occurrence of bile duct injury during cholecystectomy, no reports have examined the incidence of aberrant anatomy and its association as an independent risk factor for bile duct injury while controlling for potential confounding factors. This study involved 1289 patients. All images of MR cholangiography were reviewed and the findings, including the presence of aberrant anatomy, thickening of the gallbladder wall, and cystic duct stones—which may be related to the occurrence of bile duct injury—were recorded. The surgical outcome was compared according to the presence or absence of an aberrant anatomy and the predictive factors for bile duct injury were investigated. Aberrant anatomy was present in 11.2% of cases. The incidence of bile duct injury was significantly higher in patients with aberrant anatomy compared with patients without (3.5% versus 0.3%). By multivariate analysis, the presence of an aberrant anatomy and thickening of the gallbladder wall was an independent predictor for bile duct injury occurrence [odds ratio (OR) =16.56, P = 0.001; OR = 10.96, P = 0.006, respectively]. The presence of an aberrant anatomy and thickening of the gallbladder wall is an independent risk factor for the occurrence of bile duct injury.

Anatomic features of independent right posterior portal vein variants: Implications for left hepatic trisectionectomy

BACKGROUND

No authors have reported on the anatomic features of the independent right posterior portal vein variant and its relevance to left hepatic trisectionectomy. The purpose of this study was to review vasculobiliary systems according to portal vein anatomy, to clarify the anatomic features of the right posterior portal vein variant, and to discuss its operative implications for left hepatic trisectionectomy.

METHODS

In a radiologic study, the 3-dimensional anatomy of the portal vein, hepatic artery, and bile duct were studied in 200 patients who underwent computed tomography. In a surgical study, medical records were retrospectively reviewed for 463 patients who underwent hepatectomy for perihilar cholangiocarcinoma.

RESULTS

In the radiologic study, an independent right posterior portal vein variant was observed in 19 patients. The following observations were made in association with the portal vein variant: (1) a supraportal or combined type right posterior hepatic artery was never found; (2) an infraportal right posterior bile duct was observed at a significantly greater frequency than in patients with normal portal vein anatomy; and (3) the volume of the right posterior sector was significantly larger than in normal portal vein anatomy (37.4 ± 6.1% vs 27.3 ± 5.1%, P < .001). In the surgical study, the independent right posterior portal vein variant was observed in 41 (8.9%) patients. Of the 135 patients who underwent left hepatic trisectionectomy, 28 (20.7%) had this portal vein variant.

CONCLUSION

Independent right posterior portal vein variants exhibit anatomic features that are advantageous for performing left hepatic trisectionectomy.

Common and Uncommon Anatomical Variants of Intrahepatic Bile Ducts in Magnetic Resonance Cholangiopancreatography and its Clinical Implication

Background

Preoperative knowledge of intrahepatic bile duct (IHD) anatomy is critical for planning liver resections, liver transplantations and complex biliary reconstructive surgery. The purpose of our study was to demonstrate the imaging features of various anatomical variants of IHD using magnetic resonance cholangio-pancreatography (MRCP) and their prevalence in our population.

Material/Methods

This observational clinical evaluation study included 224 patients who were referred for MRCP. MRCP was performed in a 1.5-Tesla magnet (Philips) with SSH MRCP 3DHR and SSHMRCP rad protocol. A senior radiologist assessed the biliary passage for anatomical variations.

Results

The branching pattern of the right hepatic duct (RHD) was typical in 55.3% of subjects. The most common variant was right posterior sectoral duct (RPSD) draining into the left hepatic duct (LHD) in 27.6% of subjects. Trifurcation pattern was noted in 9.3% of subjects. In 4% of subjects, RPSD was draining into the common hepatic duct (CHD) and in 0.8% of subjects into the cystic duct. Other variants were noted in 2.6% of subjects. In 4.9% of cases there was an accessory duct. The most common type of LHD branching pattern was a common trunk of segment 2 and 3 ducts joining the segment 4 duct in 67.8% of subjects. In 23.2% of subjects, segment 2 duct united with the common trunk of segment 3 and 4 and in 3.4% of subjects segment 2, 3, and 4 ducts united together to form LHD. Other uncommon branching patterns of LHD were seen in 4.9% of subjects.

Conclusions

Intrahepatic bile duct anatomy is complex with many common and uncommon variations. MRCP is a reliable non-invasive imaging method for demonstration of bile duct morphology, which is useful to plan complex surgeries and to prevent iatrogenic injuries.

Magnetic resonance cholangiographic evaluation of intrahepatic and extrahepatic bile duct variations

Biliary anatomy and its common and uncommon variations are of considerable clinical significance when performing living donor transplantation, radiological interventions in hepatobiliary system, laparoscopic cholecystectomy, and liver resection (hepatectomy, segmentectomy). Because of increasing trend found in the number of liver transplant surgeries being performed, magnetic resonance cholangiopancreatography (MRCP) has become the modality of choice for noninvasive evaluation of abnormalities of the biliary tract. The purpose of this study is to describe the anatomic variations of the intrahepatic and extrahepatic biliary tree.

Portal vein variations in 1000 patients: surgical and radiological importance

OBJECTIVE

The purpose of the study was to evaluate the spectrum and incidence of intrahepatic portal vein (PV) variations on triphasic abdomen multidetector CT (MDCT) and to discuss the surgical and radiological implications.

METHODS

A retrospective review of 1000 triphasic MDCT abdomen scans was performed in patients sent for various liver and other abdominal pathologies between January 2014 and August 2014. A total of 967 patients (N = 967) were included in the study. The variations in branching pattern of PV were classified according to classification used by Covey et al (Covey AM, Brody LA, Getrajdman GI, Sofocleous CT, Brown KT. Incidence, patterns, and clinical relevance of variant portal vein anatomy. AJR Am J Roentgenol 2004; 183: 1055-64) and Koç et al (Koç Z, Oğuzkurt L, Ulusan S. Portal vein variations: clinical implications and frequencies in routine abdominal CT. Diagn Interv Radiol 2007; 13: 75-80).

RESULTS

Normal anatomy (Type I) was seen in 773 patients (79.94%) out of 967 patients in our study. Trifurcation (Type II) anomaly was seen in 66 (6.83%) of cases. Right posterior vein as first branch of main PV (Type III) anomaly was seen in 48 (4.96%) of cases. Type IV anomaly and Type V anomaly was seen in 26 (2.69%) and 13 (1.34%) cases, respectively. 19 cases showed other types of variations.

CONCLUSION

Variations in the hepatic PV branching patterns are commonly seen that are similar to variations in hepatic artery and biliary anatomy. Knowledge of these variations is extremely important for transplant surgeons and intervention radiologists.

ADVANCES IN KNOWLEDGE

Awareness of the variations in PV branching patterns is essential for intervention radiologists and vascular surgeons and avoids major catastrophic events.

True left-sided gallbladder with variations of bile duct and cholecystic vein

A left-sided gallbladder without a right-sided round ligament, which is called a true left-sided gallbladder, is extremely rare. A 71-year-old woman was referred to our hospital due to a gallbladder polyp. Computed tomography (CT) revealed not only a gallbladder polyp but also the gallbladder located to the left of the round ligament connected to the left umbilical portion. CT portography revealed that the main portal vein diverged into the right posterior portal vein and the common trunk of the left portal vein and right anterior portal vein. CT cholangiography revealed that the infraportal bile duct of segment 2 joined the common bile duct. Laparoscopic cholecystectomy was performed for a gallbladder polyp, and the intraoperative finding showed that the cholecystic veins joined the round ligament. A true left-sided gallbladder is closely associated with several anomalies; therefore, surgeons encountering a true left-sided gallbladder should be aware of the potential for these anomalies.

Assessment and classification of cystic arteries with 64-detector row computed tomography before laparoscopic cholecystectomy

PURPOSE

Major complications of laparoscopic cholecystectomy are bleeding and bile duct injury, and it is necessary to clearly identify structures endoscopically to keep bleeding and injury from occurring. The aim of this study was to depict the anatomical variation between cystic arteries among patients using 64-detector row spiral computed tomography (CT) prior to laparoscopic cholecystectomy.

METHODS

A total of 78 patients (31 men, 47 women) who underwent cholecystectomy were examined preoperatively using 64-detector row spiral CT between April 2012 and June 2013. The origin and number of cystic arteries and their relationship with the Calot triangle was evaluated by two independent observers. CT images were compared with laparoscopic cholecystectomy results.

RESULTS

The cystic arteries were delineated by CT in 73 of the 78 patients. The relationship between the cystic arteries and the Calot triangle was identified in 71 of the 78 patients. One cystic artery was found in 53 (73%) of the 73 patients, while two cystic arteries were found in 20 (27%) of the patients. A total of 55 (60%) of the 91 cystic arteries passed through the Calot triangle. The remaining 36 cystic arteries (40%) passed anterior, posterior, or inferior to the cystic duct. The relationship between the cystic arteries and the Calot triangle detected by CT was in agreement with the surgical records for all patients.

CONCLUSION

The configuration of the cystic arteries and their relationship with the Calot triangle can be identified using 64-detector row CT before laparoscopic cholecystectomy.

Repeated introperative cholangiography is helpful for donor safety in the procurement of right liver graft with supraportal right bile duct variants in living-donor liver transplantation

BACKGROUND

Despite recent advances in preoperative diagnostic imaging and operative techniques, biliary variation of the donor still remains a challenge in the procurement of graft. The supraportal right bile duct (BD) variant including presentation as trifurcation is a potential trap for injuring the remnant bile duct of donor.

METHODS

Before living/related-donor liver transplantation (LRLT), cholangiogram with magnetic resonance images of each donor was performed as a routine. After exploration of the donor before hilar dissection, intraoperative chloangiography (IOC) was routinely performed. Among the supraportal right bile duct variants, if the preoperative cholangiography showed a suspected trifurcation of the bile duct, we then performed 3 sessions of IOC during liver graft procurement, including prior to hilar dissection, before the division of bile ducts and after the division. We reviewed the cholangiogram and the postoperative laboratory data of a consecutive series of 25 donors of LRLT.

RESULTS

There was no division injury of the remnant bile duct of all of the donors.

CONCLUSIONS

Repeated IOC is suggested as a routine for variants of supraportal right bile ducts especially trifurcation pattern in graft procurement to avoid the injury of donor remnant bile ducts.

Biliary tract variations of the left liver with special reference to the left medial sectional bile duct in 500 patients

BACKGROUND

Among the intrahepatic bile ducts, the biliary system of the left medial sectional bile duct (B4) is known to have relatively complex patterns.

METHODS

The records of 500 patients who had been diagnosed as having hepato-pancreatico-biliary disease were retrospectively studied for anatomical biliary variations of the left liver with special reference to the drainage system of B4 using magnetic resonance images.

RESULTS

The left hepatic duct was present in 494 patients (98.8%), whereas it was lacking in 6 patients (1.2%), and these patients exhibited the following B4 confluence patterns: B4 drained into the common hepatic duct in 2 patients (.4%), the right anterior sectional bile duct in 3 patients (.6%), and the right posterior sectional bile duct in 1 patient (.2%). The left hepatic duct was absent more frequently in patients with portal venous variations than in patients with a common branching pattern (8.2% vs .4%, P = .0011).

CONCLUSION

The presently reported data are useful for obtaining a better understanding of the surgical anatomy of the biliary system of the left liver.

Correlation between portal vein anatomy and bile duct variation in 407 living liver donors

Our aim was to determine whether variant bile duct (BD) anatomy is associated with portal vein (PV) and/or hepatic artery (HA) anatomy. We examined the associations between BD anatomy and PV and/or HA anatomy in 407 living donor transplantation donors. We also examined whether the right posterior BD (RPBD) course was associated with the PV and/or HA anatomy. Variant PV, HA and BD anatomies were found in 11%, 25% and 25%, respectively, of 407 donors enrolled in this study. The presence of a variant BD was more frequently associated with a variant PV than with a normal PV (61% vs. 20%, p < 0.0001). By contrast, the presence of a variant HA was not associated with a variant BD. A supraportal RPBD was found in 357 donors (88%) and an infraportal RPBD was found in 50 donors (12%). An infraportal RPBD was significantly more common in donors with a variant PV than in donors with a normal PV (30% vs. 10%, p = 0.0004). Variant PV, but not variant HA, anatomies were frequently associated with variant BD anatomy. Additionally, an infraportal RPBD was more common in donors with a variant PV than in donors with a normal PV.

Preoperative hepatobiliary imaging: what does the radiologist need to know?

Accurate preoperative reporting is essential in guiding the surgeon in deciding when and how to operate safely and effectively. Critically, this relies on an understanding of the operative issues faced by the surgeon, which is not always appreciated by the radiologist. This paper therefore aims to address this, first focusing on relevant anatomical variants, and then issues specific to laparoscopic cholecystectomy, hepatic transplantation, and finally hepatic resection (including cholangiocarcinoma resection). Throughout the paper, there is an emphasis on associated surgical techniques to add context to the discussion.

Left hepatic trisectionectomy for hepatolithiasis with occluded left and right anterior branches of the portal vein: report of a case

A 64-year-old male was admitted to a local hospital with epigastric pain. Diagnostic imaging revealed hepatolithiasis in the atrophic left lobe. However, endoscopic intervention was impossible because of the presence of many large stones. He was referred to our hospital for surgical treatment. Enhanced multidetector-row computed tomography revealed that the right posterior portal vein (PV) was branched from the portal trunk as a first-order branch, and the bile duct of segment 3 ran caudally to the umbilical portion of the left PV. Furthermore, the umbilical portion of the left PV, which was located between the dilated bile ducts of segment 2 and segment 3, and also the right anterior PV, was occluded with thrombus. Based on these findings, he underwent left hepatic trisectionectomy. Although the indications for left hepatic trisectionectomy for hepatolithiasis are limited, it is therefore extremely important to determine the most appropriate surgical procedure based on the anatomy and findings of hepatic hilus in individual cases.

The right posterior bile duct anatomy of the donor is important in biliary complications of the recipients after living-donor liver transplantation

OBJECTIVE

To evaluate the influence of the anatomy of the right posterior bile duct (RPBD) of the donor on biliary complications in the recipients after living-donor liver transplantation (LDLT) using right hemi-liver grafts.

BACKGROUND DATA

During living-donor right hepatectomy, the RPBD was often exposed to the dissection plane. We hypothesized that biliary complications after anastomosis were increased in these cases because of potential injury to the RPBD.

METHODS

A total of 169 LDLTs using right hemi-liver grafts, with type I (typical) and type II (trifurcation) anatomy in conventional biliary classification, were retrospectively investigated. The patients were newly classified based on the confluence pattern of the RPBD. The patients were firstly divided into infraportal (IP, n = 12) and supraportal (SP, n = 157) types. SP type was subdivided into 3 groups: type A [ultrashort right bile duct (RBD), n = 20], type B (short RBD, n = 128), and type C (long RBD, n = 9). Type B was further subdivided into B-S (short caudal segment of the RPBD, n = 109) and B-L (long caudal segment of the RPBD, n = 19).

RESULTS

The biliary complication rate was 0% in type IP and type C, 40% in type A, 17.6% in type B-S, and 52.6% in type B-L (P < 0.01). In multivariate analysis, a new grouping of the RBD was a significant risk factor for biliary complications in LDLT.

CONCLUSIONS

The anatomy of the RPBD of the donor influenced the biliary outcome in the recipients. A short RBD and a long caudal segment of the RPBD of the donor were significant risk factors for biliary complications in LDLT.

Acceptable toxicity after stereotactic body radiation therapy for liver tumors adjacent to the central biliary system

PURPOSE

To evaluate biliary toxicity after stereotactic body radiation therapy (SBRT) for liver tumors.

METHODS AND MATERIALS

Among 297 consecutive patients with liver tumors treated with SBRT of 35 to 50 Gy in 5 fractions, patients who were irradiated with >20 Gy to the central biliary system (CBS), including the gallbladder, and had follow-up times >6 months were retrospectively analyzed. Toxicity profiles, such as clinical symptoms and laboratory and radiologic data especially for obstructive jaundice and biliary infection, were investigated in relation to the dose volume and length relationship for each biliary organ.

RESULTS

Fifty patients with 55 tumors were irradiated with >20 Gy to the CBS. The median follow-up period was 18.2 months (range, 6.0-80.5 months). In the dose length analysis, 39, 34, 14, and 2 patients were irradiated with >20 Gy, >30 Gy, >40 Gy, and >50 Gy, respectively, to >1 cm of the biliary tract. Seven patients were irradiated with >20 Gy to >20% of the gallbladder. Only 2 patients experienced asymptomatic bile duct stenosis. One patient, metachronously treated twice with SBRT for tumors adjacent to each other, had a transient increase in hepatic and biliary enzymes 12 months after the second treatment. The high-dose area >80 Gy corresponded to the biliary stenosis region. The other patient experienced biliary stenosis 5 months after SBRT and had no laboratory changes. The biliary tract irradiated with >20 Gy was 7 mm and did not correspond to the bile duct stenosis region. No obstructive jaundice or biliary infection was found in any patient.

CONCLUSIONS

SBRT for liver tumors adjacent to the CBS was feasible with minimal biliary toxicity. Only 1 patient had exceptional radiation-induced bile duct stenosis. For liver tumors adjacent to the CBS without other effective treatment options, SBRT at a dose of 40 Gy in 5 fractions is a safe treatment with regard to biliary toxicity.

Anatomic variations of the right hepatic duct: results and surgical implications from a cadaveric study

Purpose. Thorough understanding of biliary anatomy is required when performing surgical interventions in the hepatobiliary system. This study describes the anatomical variations of right bile ducts in terms of branching and drainage patterns, and determines their frequency. Methods. We studied 73 samples of cadaveric material, focusing on the relationship of the right anterior and posterior segmental branches, the way they form the right hepatic duct, and the main variations of their drainage pattern. Results. The anatomy of the right hepatic duct was typical in 65.75% of samples. Ectopic drainage of the right anterior duct into the common hepatic duct was found in 15.07% and triple confluence in 9.59%. Ectopic drainage of the right posterior duct into the common hepatic duct was discovered in 2.74% and ectopic drainage of the right posterior duct into the left hepatic duct in 4.11%. Ectopic drainage of the right anterior duct into the left hepatic ductal system and ectopic drainage of the right posterior duct into the cystic duct was found in 1.37%. Conclusion. The branching pattern of the right hepatic duct was atypical in 34.25% of cases. Thus, knowledge of the anatomical variations of the extrahepatic bile ducts is important in many surgical cases.

Inaccurate preoperative imaging assessment on biliary anatomy not increases biliary complications after living donor liver transplantation

BACKGROUNDS AND AIMS

Accurate assessment of graft bile duct is important to plan surgical procedure. Magnetic resonance cholangiopancreatography (MRCP) has become an important diagnostic procedure in evaluation of pancreaticobiliary ductal abnormalities and has been reported as highly accurate. We aim to estimate the efficacy of preoperative MRCP on depicting biliary anatomy in living donor liver transplantation (LDLT), and to determine whether inaccurate preoperative imaging assessment would increase the biliary complications after LDLT.

METHODS

The data of 118 cases LDLT were recorded. Information from preoperative MRCP was assessed using intraoperative cholangiography (IOC) as the gold standard. The possible risk factors of recipient biliary complications were analyzed.

RESULTS

Of 118 donors, 84 had normal anatomy (type A) and 34 had anatomic variants (19 cases of type B, 9 cases of type C, 1 case of type E, 2 cases of type F and 3 cases of type I) confirmed by IOC. MRCP correctly predicted all 84 normal cases and 17 of 34 variant cases, and showed an accuracy of 85.6% (101/118). The incidence of biliary complications was comparable between cases with accurate and inaccurate classification of biliary tree from MRCP, and between cases with normal and variant anatomy of bile duct. While cases with graft duct opening ≤5mm showed a significant higher incidence of total biliary complications (21.1% vs. 6.6%, P=0.028) and biliary stricture (10.5% vs. 1.6%, P=0.041) compared with cases with large duct opening >5mm.

CONCLUSION

MRCP could correctly predict normal but not variant biliary anatomy. Inaccurate assessment of biliary anatomy from MRCP not increases the rate of biliary complications, while small-sized graft duct may cause an increase in biliary complications particularly biliary stricture after LDLT.

Clinical significance of left trisectionectomy for perihilar cholangiocarcinoma: an appraisal and comparison with left hepatectomy

OBJECTIVE

To review our experiences with left-sided hepatectomy for perihilar cholangiocarcinoma, to compare left hepatectomy with left trisectionectomy, and to evaluate the clinical significance of left trisectionectomy from the viewpoint of surgical oncology.

BACKGROUND

Only 4 large case series have been reported on left trisectionectomy, with only a few patients diagnosed with perihilar cholangiocarcinoma. Therefore, the oncologic advantage of left trisectionectomy compared with left hepatectomy for perihilar cholangiocarcinoma is still unclear.

METHODS

This study involved 201 patients who underwent left-sided hepatectomy for perihilar cholangiocarcinoma (86 trisectionectomies and 115 hepatectomies). Surgical outcome and survival were compared between the 2 types of hepatectomy. The length of the resected right posterior bile duct was also measured.

RESULTS

Patients who underwent trisectionectomy had more advanced tumors, thus requiring combined vascular and/or other organ resection. Operative time and blood loss were significantly greater in trisectionectomy than in hepatectomy; therefore, overall morbidity was significantly higher in the former (59.3% vs 33.0%, P < 0.001). Mortality was similar (1.2% vs 0.9%) in both techniques. The length of the resected supraportal right posterior bile duct was significantly longer in trisectionectomy than in hepatectomy (20.7 ± 6.4 vs 13.6 ± 5.2 mm, P < 0.001). However, there was no difference in length of the infraportal type right posterior bile duct. The percentage of negative radial and distal common bile duct margins was similar, but the percentage of negative right posterior bile duct margins was significantly higher in trisectionectomy than in hepatectomy (97.7% vs 89.6%, P = 0.027). Overall, R0 resection was achieved in 84.9% of patients with trisectionectomy and in 70.4% of patients with hepatectomy (P = 0.019). Survival rates were similar between patients with trisectionectomy and those with hepatectomy (36.8% vs 34.0% at 5-year), despite the fact that the former had more advanced disease.

CONCLUSIONS

Left trisectionectomy for perihilar cholangiocarcinoma, although technically demanding, can be performed with similar mortality rates as left hepatectomy. From an oncologic viewpoint, this operation can increase the number of negative proximal ductal margins, leading to a high proportion of R0 resection, and, in turn, to improved survival rates of patients with advanced left-sided perihilar cholangiocarcinoma.

CT and MR cholangiography: advantages and pitfalls in perioperative evaluation of biliary tree

Recent developments in imaging technology have enabled CT and MR cholangiopancreatography (MRCP) to provide minimally invasive alternatives to endoscopic retrograde cholangiopancreatography for the pre- and post-operative assessment of biliary disease. This article describes anatomical variants of the biliary tree with surgical significance, followed by comparison of CT and MR cholangiographies. Drip infusion cholangiography with CT (DIC-CT) enables high-resolution three-dimensional anatomical representation of very small bile ducts (e.g. aberrant branches, the caudate branch and the cystic duct), which are potential causes of surgical complications. The disadvantages of DIC-CT include the possibility of adverse reactions to biliary contrast media and insufficient depiction of bile ducts caused by liver dysfunction or obstructive jaundice. Conventional MRCP is a standard, non-invasive method for evaluating the biliary tree. MRCP provides useful information, especially regarding the extrahepatic bile ducts and dilated intrahepatic bile ducts. Gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid-enhanced MRCP may facilitate the evaluation of biliary structure and excretory function. Understanding the characteristics of each type of cholangiography is important to ensure sufficient perioperative evaluation of the biliary system.

Fetal intrahepatic gallbladder and topographical anatomy of the liver hilar region and hepatocystic triangle

The fetal gallbladder (GB) is embedded in a deep fossa surrounded by the liver parenchyma. Using 15 specimens with intrahepatic GB (crown-rump length 45-92 mm; approximately 9-13 weeks of gestation), we assessed the fetal topographical anatomy of the hepatocystic triangle and the porta hepatis. The cystic duct displayed a long upward course (0.9-4.5 mm along the supero-inferior axis) from the GB, along the duodenum, to the common bile duct in the hepatoduodenal ligament, via an independent mesentery separated from liver parenchyma by a recess of the peritoneal cavity. Notably, the course varied in length among specimens, not among stages. At the porta hepatis, we were able to distinguish the supraportal course of the posterior right hepatic duct overriding a portal vein branch to segment 8 (6/15) from the other, infraportal course (9/15). In the latter type, the portal vein bifurcation was superior to the cystic duct course. Two margins of the hepatocyctic triangle were very long in fetuses because of the inferiorly located intrahepatic GB. Thus, the triangle seems to be difficult to identify in prenatal ultrasound. During changes in location after 9 weeks, the GB fundus remains attached to the liver because the cystic artery was often embedded in the liver parenchyma. A failure in the embedding and re-exposure process of the GB may result in anomalous peritoneal folds around the GB.

"Supraportal" right posterior hepatic artery: an anatomic trap in hepatobiliary and transplant surgery

BACKGROUND

A supraportal right posterior hepatic artery (RPHA), which runs cranially to the right portal vein and goes to the liver, has never been described.

METHODS

The course of the RPHA to the right portal vein was evaluated, using (1) computed tomography (CT) arteriography and portography in 300 patients who underwent multidetector row CT (radiologic study) and (2) operative records in 203 patients who underwent left-sided hepatectomy for perihilar cholangiocarcinoma (surgical study).

RESULTS

In the radiologic study, an infraportal type RPHA was observed in 239 (79.7%) patients, a supraportal type in 35 (11.7%), and a combined type in 26 (8.7%). In the surgical study, an infraportal type was observed in 179 (88.2%) patients, a supraportal type in 11 (5.4%), and a combined type in 13 (6.4%). In two patients with the combined type RPHA, the supraportal hepatic artery of the right posterior superior segment (A7) was injured during surgery. In another two patients with advanced carcinoma involving the supraportal PRHA, combined hepatic artery resection and reconstruction was necessary. Overall, in 4 (17.4%) of the 24 hepatectomized patients with supraportal or combined type RPHA, iatrogenic injury during surgery or cancer invasion of the hepatic artery occurred due to the course of the RPHA itself. In contrast, 179 hepatectomized patients with infraportal type RPHA did not have such course-dependent complications.

CONCLUSIONS

The supraportal RPHA runs just beneath the right hepatic duct, which may function as an anatomic trap during hepatobiliary and transplant surgery.