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.

Couinaud Type A communicating accessory bile duct: report of a case.

BACKGROUND: Communicating accessory bile ducts are defined as ducts that communicate between major biliary channels but do not drain individual segments of the liver. The Couinaud Type A communicating accessory bile duct is a rare anomaly where an aberrant duct connects the right main hepatic duct to the common hepatic duct without segmental drainage. There are very few reports of this anomaly in the literature to date. CASE PRESENTATION: A 75-year-old male who died of ischemic heart disease donated his body for cadaveric dissection, which included careful attention to the anatomy of the hepatic hilum. During dissection, it was found that the right hepatic duct was duplicated and an accessory duct drained directly into the common hepatic duct. Although rare and difficult to visualize even with modern preoperative imaging techniques, sound knowledge of this rare anatomic variation is imperative to avoid inadvertent intraoperative biliary injuries which can lead to severe morbidity. CONCLUSIONS: An aberrant bile duct from the right hepatic duct to the common hepatic duct (Couinaud Type A) is an uncommon accessory bile duct that one must be aware of when performing complex hepatobiliary procedures such as right liver resection for living-related donation. Detailed preoperative imaging and careful dissection with anticipation of anomalous anatomy are of the utmost importance for the safe conduct of hepatic surgery.

[The new classifications of biliary tract diseases based on actual anatomy].

In order to facilitate the treatment strategies for biliary tract injury, hilar cholangiocarcinoma, bile duct tumor thrombus, cholangiocellular carcinoma and bile duct cystic dilatation, many classifications have been made, even more than 10 types for one disease. Each type is represented by numbers or English alphabet, which are not only confusing but also difficult to remember. The Academician Mengchao Wu divided the liver into five sections and four segments base on its anatomy, this classification is very direct and visual, thus had been using till now. In order to overcome those complicated problems, it is considered to develop a new classification based on actual anatomic location similar to that for liver cancer, which is easy to remember and to directly determine the treatment strategy. All kinds of classifications have their own characteristics and advantages and disadvantages. This practical classifications avoid the complexity and may be useful for clinicians.

Reference limits for hepatic bile duct-to-arteriole and bile duct-to-portal tract ratios in healthy cats.

OBJECTIVE To establish reference limits for hepatic bile duct-to-arteriole ratio (BD:A) and bile duct-to-portal tract ratio (BD:PT) in healthy cats and assess whether these parameters could be used to support a diagnosis of biliary ductopenia in cats. SAMPLE Hepatic biopsy samples from healthy cats (n = 20) and cats with ductopenia (2). PROCEDURES Hepatic biopsy samples from healthy cats were used to count the number of bile ducts and hepatic arterioles in 20 portal tracts for each cat. Mean BD:A and mean BD:PT for each cat were calculated, and these values were used to determine reference limits for mean BD:A and mean BD:PT. Results of histologic evaluation, including immunohistochemical staining in some instances, were compared for healthy cats versus cats with ductopenia. RESULTS Of the 400 portal tracts from healthy cats, 382 (95.5%) and 396 (99.0%) had BD:A and BD:PT, respectively, ≥ 1.0, with less variability in BD:A. Mean BD:A and BD:PT were markedly lower in both cats with ductopenia, compared with values for healthy cats. However, only mean BD:A for cats with ductopenia was below the reference limit of 0.59. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that systematic evaluation of BD:A, with a lower reference limit of 0.59 to define biliary ductopenia in cats, may be a discrete and easily applied morphometric tool to enhance detection of ductopenia in cats. However, application of this ratio required evaluation of ≥ 20 portal tracts with cross-sectioned portal elements to determine a mean BD:A value.

Comparison of the Clinicopathologic Characteristics of Intraductal Papillary Neoplasm of the Bile Duct according to Morphological and Anatomical Classifications.

BACKGROUND: Intraductal papillary neoplasm of the bile duct (IPNB) is a recently defined entity and its clinical characteristics and classifications have yet to be established. We aimed to clarify the clinical features of IPNB and determine the optimal morphological classification criteria. METHODS: From 2003 to 2016, 112 patients with IPNB who underwent surgery were included in the analysis. After pathologic reexamination by a specialized biliary-pancreas pathologist, previously suggested morphological and anatomical classifications were compared using the clinicopathologic characteristics of IPNB. RESULTS: In terms of histologic subtypes, most patients had the intestinal type (n = 53; 48.6%) or pancreatobiliary type (n = 33; 30.3%). The simple "modified anatomical classification" showed that extrahepatic IPNB comprised more of the intestinal type and tended to be removed by bile duct resection or pancreatoduodenectomy. Intrahepatic IPNB had an equally high proportion of intestinal and pancreatobiliary types and tended to be removed by hepatobiliary resection. Morphologic classifications and histologic subtypes had no effect on survival, whereas a positive resection margin (75.9% vs. 25.7%; P = 0.004) and lymph node metastasis (75.3% vs. 30.0%; P = 0.091) were associated with a poor five-year overall survival rate. In the multivariate analysis, a positive resection margin and perineural invasion were important risk factors for survival. CONCLUSION: IPNB showed better long-term outcomes after optimal surgical resection. The "modified anatomical classification" is simple and intuitive and can help to select a treatment strategy and establish the proper scope of the operation.

Clinical Implications of Biliary Confluence Pattern for Bismuth-Corlette Type IV Hilar Cholangiocarcinoma Applied to Hemihepatectomy.

BACKGROUND: Since biliary variations are commonly seen, our aims are to clarify these insidious variations and discuss their surgicopathologic implications for Bismuth-Corlette (BC) type IV hilar cholangiocarcinoma (HC) applied to hemihepatectomy. METHODS: Three-dimensional images of patients with distal bile duct obstruction (n = 97) and advanced HC (n = 79) were reconstructed and analyzed retrospectively. Normal biliary confluence pattern was defined as the peripheral segment IV duct (B4) joining the common trunk of segment II (B2) and segment III (B3) ducts to form the left hepatic duct (LHD) that then joined the right hepatic duct (RHD). The lengths from left and right secondary biliary ramifications to the right side of the umbilical portion of the left portal vein (Rl-L) and the cranio-ventral side of the right portal vein (Rr-R) were measured, respectively, and compared with the resectable bile duct length in HCs. Surgicopathologic findings were compared between different BC types. RESULTS: The resectable bile duct length in right hemihepatectomy for eradication of type IV tumors was significantly longer than the Rl-L length in normal biliary configuration (17.4 ± 1.8 and 10.3 ± 3.4 mm, respectively, p < 0.001), and type III variation (B2 joining the common trunk of B3 and B4) was the predominant configuration (53.8%). The resectable length in left hemihepatectomy for eradication of type IV tumors was comparable with the Rr-R length in RHD absent cases (15.2 ± 2.5 and 16.4 ± 2.6 mm, respectively, p = 0.177) but significantly longer than that in normal configuration (p < 0.001). The estimated length was 8.5 ± 2.0 mm in unresectable cases. There was no significant difference between type III and IV tumors, except for the rate of nodal metastasis (29.7 and 76.0%, respectively, p < 0.001). CONCLUSION: Hemihepatectomy might be selected for curative-intent resection of BC type IV tumors considering the advantageous biliary variations, whereas anatomical trisegmentectomy is recommended for the resectable bile duct length less than 10 mm. Biliary variations might result in excessive classification of BC type IV but require validation on further study.

La vía biliar intrahepática: clasificación anátomo-quirúrgica con base colangiográfica / Intrahepatic biliary ducts: anatomic and surgical classification after cholangiographic findings

Las variaciones en la constitución de la vía biliar son muy frecuentes. Su conocimiento adquiere importancia en distintos procedimientos quirúrgicos, como la colocación de un drenaje en la vía biliar o una colecistectomía. Sin embargo, el cirujano a menudo la visualiza por primera vez durante el acto quirúrgico, y debe lidiar con clasificaciones complejas para poder comprenderlas. El objetivo de este trabajo es presentar una clasificación sencilla y de rápida interpretación. Se analizaron 100 estudios colangiográficos y se realizaron 10 disecciones cadavéricas, como apoyo al estudio colangiográfico. A partir de los resultados obtenidos, se propuso la siguiente clasificación: Conducto hepático derecho "típico", cuando éste reúne la bilis de toda la porción hepática derecha, o "dividido", cuando sus ramas desembocan separadamente en la vía biliar principal. Conducto hepático izquierdo "típico" o "dividido", siguiendo el mismo criterio. Conducto hepático "central", cuando las secciones parasagitales de ambas porciones hepáticas, derecha e izquierda, se reúnen en un solo conducto. Respecto a la confluencia de los conductos biliares, puede clasificarse en "típica" precisamente cuando ambos conductos hepáticos también lo son, "triple confluencia" cuando uno o ambos conductos hepáticos se encuentran divididos y todos ellos confluyen en un punto, o "escalonada" cuando uno de ellos se encuentra dividido y la confluencia se realiza a distinta altura, en ocasiones con algún conducto segmentario. Creemos que esta clasificación resulta de fácil aplicación por su sencillez, permitiendo identificar todas las estructuras de la vía biliar rápidamente aún sin contar con estudios previos, colaborando de esta manera en una cirugía más segura.

Variations in intrahepatic biliary ducts are frequent. Its knowledge is of great importance when facing certain procedures such as drainage or a simple cholecystectomy to avoid iatrogenic lesion or incomplete drainage of the biliary tract. Nevertheless, it is during surgery that the surgeon attempts to see it for the first time, and must deal with complex classifications in order to recognize the ducts. This paper aims to suggest an easy and quick way to interpret and simple classification. 100 cholangiograms were studied and 10 cadaveric specimens were analyzed to support radiologic findings. As a result, we propose the following classification: Right "typical" biliary duct, when all the bile produced in the right hemiliver is drained by a single duct, or "divided" when sectional ducts reach separately the main bile duct. The same applies to the left hepatic ducts, "typical" or "divided". When both paramedian sections are drained by the same duct, there is a "Central" hepatic duct The biliary confluence may be "typical", when both hepatic ducts are also typical, "triple confluence" when one or both hepatic duct are divided and reach the main bile duct in the same place, or "staggered (selved) confluence" (etagée) when one of the ducts is divided and reaches the main bile duct separately from the others. This name is even proper if a segmentary duct reaches the main bile duct. We think this classification is easy to use due to its simplicity, allowing the surgeon to quickly identify each biliary duct and get through the surgery safely.

Surgical and Radiological Studies on the Length of the Hepatic Ducts.

BACKGROUND: Right-sided hepatectomy is often selected for perihilar cholangiocarcinoma, due to the anatomic consideration that "the left hepatic duct is longer than that of the right hepatic duct". However, only one study briefly mentioned the length of the hepatic ducts. Our aim is to investigate whether the consideration is correct. METHODS: In surgical study, the lengths of the resected bile duct were measured using pictures of the resected specimens in 475 hepatectomized patients with perihilar cholangiocarcinoma. In radiological study, the estimated lengths of the bile duct to be resected were measured using cholangiograms reconstructed from computed tomography images in 61 patients with distal bile duct obstruction. RESULTS: In surgical study, the length of the resected left hepatic duct was 25.1 ± 6.4 mm in right trisectionectomy (n = 37) and 14.9 ± 5.7 mm in right hepatectomy (n = 167). The length of the right hepatic duct was 14.1 ± 5.7 mm in left hepatectomy (n = 149) and 21.3 ± 6.4 mm in left trisectionectomy (n = 122). In radiological study, the lengths of the bile duct corresponding to the surgical study were 34.1 ± 7.8, 22.4 ± 7.1, 20.8 ± 4.8, and 31.6 ± 5.3 mm, respectively. Both studies determined that the lengths of the resected bile ducts were (1) similar between right and left hepatectomies, (2) significantly shorter in right hepatectomy than in left trisectionectomy, and (3) the longest in right trisectionectomy. CONCLUSIONS: The aforementioned anatomical assumption is a surgeon's biased view. Based on our observations, a flexible procedure selection is recommended.

Identification of a safe and adequate division point of the left-sided bile duct with magnetic resonance cholangiography during donor left lateral sectionectomy.

BACKGROUND: Multiple bile duct (BD) openings on the graft can cause postoperative BD-related complications as the result of their small orifices and multiple anastomoses. This study aimed to determine a safe and adequate BD division point during donor left lateral sectionectomy. METHODS: Left BD was classified into type I: B4 enters the common trunks of B2 and B3; type II: B2 joins the common channels of B3 and B4; or type III: B2, B3, and B4 join. We assessed the chance of multiple openings with 3 BD types in 43 left lateral living donor grafts from January 2004 to January 2011. We also analyzed the potential for multiple openings and right-sided BD injury, based on BD types, during left lateral sectionectomy according to the distance from the crossing point of the right lateral border of the umbilical portion of the left portal vein at the left BD (point U) via preoperative magnetic resonance imaging from another 90 living donors who underwent several types of hepatectomy from January 2012 to December 2012. RESULTS: There was a statistically marginal relevance for multiple openings between BD type I and type II (33.3% in type II vs 7.4% in type I, P = .078), and the optimal BD division points were different by BD types (right-side 5 mm from point U in type I; 10 mm in type II; and 12 mm in type III). CONCLUSION: The safe and adequate BD division point should be determined according to the left BD types during living donor left lateral sectionectomy.

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.

Anatomic variations of the intrahepatic bile ducts: analysis of magnetic resonance cholangiopancreatography in 1011 consecutive patients.

OBJECTIVES: The aim of the study was to evaluate the frequency of anatomic variations of the hepatic duct bifurcation using magnetic resonance cholangiopancreatography (MRCP). METHODS: A total of 1,160 consecutive patients, referred to our department for MRCP due to suspected pancreatobiliary disease or before liver transplantation, were reviewed retrospectively. A total of 149 patients with less than optimal results due to imaging limitations or secondary differentiations of bile duct anatomy were excluded from the study. The final study population was composed of 1,011 cases. RESULTS: Of the 1,160 patients, 149 were excluded from the analysis. Typical biliary anatomy was observed in 79.4% of cases, but female potential living liver donors more frequently presented an anatomic variation. Typical anatomy was present in 75.7% of the females and 85.3% of the males (p < 0.05). Out of the remaining 1,011 patients, 208 (20.57%) were diagnosed with different levels of various anatomic variations of the intra- and extrahepatic biliary ducts. Of the 208 cases with diagnosed variations, 204 (98.07%) and 4 (1.92%) turned out to have 1 and 2 different variations, respectively. The trifurcation variant was observed in 81 cases (8.01%), while 73 subjects (7.23%) had an aberrant right biliary duct draining into the common hepatic duct. A right dorsocaudal branch draining into the left hepatic duct was present in 42 cases (4.15%). Four cases (0.4%) had 2 different variations and 8 (0.8%) had uncommon anatomic variations. CONCLUSIONS: Typical intrahepatic biliary anatomy is present in about 80% of the inhabitants of the Aegean region of Turkey, but anatomic variants seem to be more frequent in females as compared to males. Trifurcation was the most common anatomic variation in our study population. The presence of an aberrant right hepatic duct emptying into the common hepatic duct was the second most common observation amongst our findings.

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.

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.

Onset of apoptosis in the cystic duct during metamorphosis of a Japanese lamprey, Lethenteron reissneri.

A nonparasitic lamprey in Japan, Lethenteron reissneri, stops feeding prior to the commencement of metamorphosis. Resumption of feeding cannot take place due to major alterations in the digestive system, including loss of the gall bladder (GB) and biliary tree in the liver. This degeneration of bile ducts is considered to depend on programmed cell death or apoptosis, but molecular evidence of apoptosis remains lacking. Using terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) staining and immunohistochemistry with an antibody against active caspase-3, we showed that epithelial cells of the cystic duct (CD) and GB became TUNEL-positive by the early metamorphosing stage. Immunohistochemical staining of active caspase-3, a key mediator in the apoptotic cascade, showed that the apoptotic signal was initiated in the region around the CD in the late larval phase. In later stages, active caspase-3-positive epithelial cells were also observed in the large intrahepatic bile duct (IHBD) and peripheral small IHBDs. At the early metamorphosing stage, bile canaliculi between hepatocytes were dilated and displayed features resembling canaliculi in cholestasis. Onset of apoptosis around the CD, which is the pathway for the storage of bile juice, and progression of apoptosis towards the large IHBD, which is the pathway for the secretion of bile juice, may lead to temporary intrahepatic cholestasis. The present study represents the first precise spatial and temporal analysis of apoptosis in epithelial cells of the biliary tract system during metamorphosis of any lamprey species.

[Anatomy problems in the radical resection for hilar cholangiocarcinoma].

OBJECTIVE: To analyze the clinical data, surgical strategies and results from the patients with hilar cholangiocarcinoma (HCCA), and to explore the anatomic factors related to the radical resection. METHODS: The data from 52 patients with HCCA who underwent radical resection between January 1984 to December 2008 were investigated retrospectively, which included clinical diagnosis, Bismuth-Corlette classification, pathologic features, surgical procedures and follow-up results. RESULTS: According to the Bismuth-Corlette classification, 5, 12, 6, 16 and 13 patients belonged to type I, II, IIIa, IIIb and IV respectively. There were 24 cases underwent combined hepatic lobectomy. The 1-, 3- and 5-year survival rates were 78.8%, 36.4% and 12.1% respectively. Postoperative complications rate was 30.8% with the 3.8% mortality rate. The frequency of surgical complications was significantly higher in patients with higher level of serum total bilirubin (> 340 micromol/L) than that in patients with a relatively lower one (170 micromol/L) before operation (P < 0.05). CONCLUSIONS: Some anatomical factors should be considered during the radical resection of hilar cholangiocarcinoma, especially evaluation of potential hepatectomy, resection of caudate lobe, hepatic artery resection and/or reconstruction. The prognosis of the patients underwent R(0) radial resection could be significantly improved.

Hilar liver resection in dogs.

OBJECTIVE: To describe hepatic vasculobiliary anatomy important to hilar liver lobe resection in the dog. STUDY DESIGN: Experimental study. ANIMALS: Canine cadavers (n=7). METHODS: The vasculobiliary system of 7 fresh canine livers was injected with a polymer. The parenchyma was dissected at the level of the hilus to determine the vascular and biliary supply to each liver lobe, and then macerated with a corrosion preparation. The information gathered was used to describe a surgical approach for hilar liver lobe resection. RESULTS: Each liver lobe had a single hepatic artery and biliary duct. The location of these structures was consistent, although minor variations existed (dorsal versus ventral to the lobar portal vein) in the left lateral lobe and papillary process in 2 specimens. Most liver lobes (34/49) were supplied by 1 lobar portal vein and drained by 1 lobar hepatic vein (39/49). The location of the portal and hepatic veins was consistent among specimens. CONCLUSIONS: The left division is the most mobile of the liver lobes and each lobe can be removed separately or en bloc. Because of the location of the hepatic veins, the central division is best removed as a single unit. The right lateral lobe can be removed individually or together with the caudate process. The papillary process is removed by itself. CLINICAL RELEVANCE: A hilar liver lobectomy technique can provide an alternative approach to conventional procedures for tumors that encroach upon the hilus of the liver.

Segment-growing hierarchical model for bile duct detection in MRCP.

Magnetic resonance cholangiopancreatography (MRCP) is the popular diagnostic imaging sequence for the diagnosis and surgery workup for the pancreatobiliary system and liver. The technique is relatively noisy and suffers from imaging characteristics such as the partial volume effect and varying acquisition orientation, making automatic analysis of the images difficult. This paper explores some of the popular image processing techniques with the goal of selecting suitable features in MRCP images, as a basis for preliminary computer-aided diagnosis systems in biliary structure image reconstruction and disease detection. Visual results and observations are given and analyzed. The findings support that many popular techniques such as texture analysis fail to highlight the structures of interest in MRCP images, whereas multi-scale, multi-resolution and dynamic thresholding achieve better success. The proposed multi-scale combination technique known as the Segment-Growing Hierarchical Model produced good visual results for detection of the bile ducts.

Anatomic variations in intrahepatic bile ducts in a north Indian population.

BACKGROUND AND AIM: In the present study, we described the anatomical variations in the branching patterns of intrahepatic bile ducts (IHD) and determined the frequency of each variation in north Indian patients. There are no data from India. METHODS: The study group consisted of 253 consecutive patients (131 women) undergoing endoscopic retrograde cholangiograms for different indications. Anatomical variations in IHD were classified according to the branching pattern of the right anterior segmental duct (RASD) and the right posterior segmental duct (RPSD), presence or absence of first-order branch of left hepatic duct (LHD) and of an accessory hepatic duct. RESULTS: Anatomy of the IHD was typical in 52.9% of cases (n = 134), showing triple confluence in 11.46% (n = 29), anomalous drainage of the RPSD into the LHD in 18.2% (n = 46), anomalous drainage of the RPSD into the common hepatic duct (CHD) in 7.1% (n = 18), drainage of the right hepatic duct (RHD) into the cystic duct 0.4% (n = 1), presence of an accessory duct leading to the CHD or RHD in 4.7% (n = 12), individual drainage of the LHD into the RHD or CHD in 2.4% (n = 6), and unclassified or complex variations in 2.7% (n = 7). None had anomalous drainage of RPSD into the cystic duct. CONCLUSION: The branching pattern of IHD was atypical in 47% patients. The two most common variations were drainage of the RPSD into the LHD (18.2%) and triple confluence of the RASD, RPSD, and LHD (11.5%).

Congenital anomalies and variations of the bile and pancreatic ducts: magnetic resonance cholangiopancreatography findings, epidemiology and clinical significance.

PURPOSE: The objective of this paper is to document the magnetic resonance cholangiopancreatography (MRCP) findings and the epidemiology of congenital anomalies and variations of the bile and pancreatic ducts and to discuss their clinical significance. MATERIALS AND METHODS: Three-hundred and fifty patients of both sexes (150 females, 200 males, age range 0-76 years, average age 38 years) underwent MRCP for clinically suspected lithiasic, neoplastic or inflammatory disease of the bile and pancreatic ducts. Patients were imaged with a 1.5-T superconductive magnet (Magnetom Vision, Siemens, Erlangen, Germany), a four-channel phased-array body coil, breath-hold technique, with multislice T2-weighted half-Fourier acquisition single-shot turbo spin echo (HASTE), MIP reconstructions, and a single-shot T2-weighted turbo-spin-echo sequence rapid acquisition with relaxation enhancement (RARE) with different slice thicknesses. Studies in oncological patients were completed with fat saturation 3D T1 gradient-echo sequences during the intravenous injection of gadolinium diethylene triamine pentaacetate acid (DTPA) (0.2 ml/kg). RESULTS: MRCP demonstrated recurrent and therefore normal bile and pancreatic ducts in 57% of patients. In the remaining 42.3%, it documented anatomical variants (41%) and congenital anomalies (1.3%). Variants of the intrahepatic bile duct were seen in 21% of cases: crossover anomaly (6.7%), anterior branch of the right hepatic duct draining the IV and VII segments that flow together with the left bile duct (3.1%) and anterior and posterior branches of the right hepatic duct that flow together with the common hepatic duct (3.3%). Variants of the extrahepatic bile ducts were present in 8.8% of patients: low insertion of the cystic duct into the common hepatic duct (4.5%), emptying of the cystic duct into the right hepatic duct (2.7%) and a second-order large branch draining into the cystic duct (1.6%). MRCP identified a double gall bladder in 3% of patients and anatomical variants of the biliopancreatic system in 8.2%: pancreas divisum (5.2%) and a long sphincter of Oddi (3%). Finally, congenital anomalies were diagnosed in 1.3% of cases: bile duct cysts (0.3%), atresia of the bile ducts (0.3%) and multiple biliary hamartomatosis (0.7%). CONCLUSIONS: The congenital anomalies and anatomical variants of the bile and pancreatic ducts present a complex spectrum of frequent alterations, which are worthy of attention in both the clinical and surgical settings and are readily identified by MRCP.

Postliver transplantation vascular and biliary surgical anatomy.

Imaging and management of postliver transplantation complications require an understanding of the surgical anatomy of liver transplantation. There are several methods of liver transplantation. Furthermore, liver transplantation is a complex surgery with numerous variables in its 4 anastomoses: (1) arterial anastomosis, (2) venous inflow (portal venous) anastomosis, (3) venous outflow (hepatic vein, inferior vena cava, or both) anastomosis, and (4) biliary/biliary-enteric anastomosis. The aim of this chapter is to introduce the principles of liver transplant surgical anatomy based on anastomotic anatomy. With radiologists as the target readers, the chapter focuses on the inflow and outflow connections and does not detail intricate surgical techniques or intraoperative maneuvers, operative stages, or vascular shunting.