Classification of variant portal vein anatomy based on three-dimensional CT: surgical implications.

PURPOSES: The purpose of this study was to develop a new and more comprehensive classification system for portal vein (PV) variations using three-dimensional visualization and evaluation (3DVE) and to discuss the prevalence rates and clinical implications of the variants. METHODS: The anatomies of PVs were tracked and analyzed by using three-dimensional visualization of CT images acquired between 2013 and 2022. Scans from 200 adults were evaluated and a total of 178 patients (N = 178) were included in the study. The new classification system, named BLB classification, was developed based on the level of the absent PV branch in each variant anatomy. RESULTS: Using the BLB classification system, PVs were divided into thirteen subtypes. Only 82.6-84.8% of the portal veins of the 178 patients were depicted in Atri's, Cheng's or Covey's classification, compared with 100% identified by the BLB classification. The BLB classification was validated against external data sets from previous studies, with 97.0-98.9% of patients classified by the BLB system. CONCLUSION: Variant PV anatomies are more commonly seen based on 3DVE than in previous reports. The BLB classification covers almost all portal vein variants and may be used for planning liver surgery.

Evaluation of ventral branches of segment VI portal vein relative to the right hepatic vein in laparoscopic right anterior sectionectomy.

INTRODUCTION: The right intersectional plane and the right hepatic hilum were noted too often exhibit anatomical variations, making difficult the laparoscopic right anterior sectionectomy (LRAS). METHODS: We analyzed the anatomical features employing 3D-CT images of 55 patients, and evaluated these features according to the course of ventral branches of segment VI of the portal vein (PV, P6a) relative to the right hepatic vein (RHV). RESULTS: P6a run on the dorsal side of RHV in 32 patients (58%, Dorsal-P6a) and the ventral side of RHV in 23 (42%, Ventral-P6a). Ventral-P6a had more patients with S6 partially drained by middle hepatic vein (MHV, 39% vs. 0%, P < 0001), the narrower angle between the anterior and posterior branches of PV (73.1° vs. 93.8°, P = 0.006), the wider angle between the RHV and inferior vena cava  (54.3° vs. 44.3°, P < 0.001), and more steeply pitched angle between S6 and S7 along the RHV (140.6° vs. 162.0°, P < 0.001) compared to Dorsal-P6a. CONCLUSION: In LRAS for Dorsal-P6a patients, the transection surface was relatively flat. In LRAS for Ventral-P6a patients, the narrow space between anterior and posterior glissons makes difficult the glissonean approach. The transection plane was steeply pitched, and RHV was partially exposed. S6 was often partially drained to MHV in 39% of the Ventral-P6a patients, which triggers congestion during liver transection of a right intersectional plane after first splitting the confluence of this branch.

Sonographic and Anatomical Evaluation of the Liver and Portal Vein Reference Values / Evaluación Ecográfica y Anatómica de los Valores de Referencia del Hígado y la Vena Porta

SUMMARY: This paper's aim is a morphometric evaluation of liver and portal vein morphometry using ultrasonography in healthy Turkish population. This study was carried out with 189 subjects (107 females, 82 males). The demographic data and the body surface area were calculated. The longitudinal axis of the liver for two lobes, diagonal axis or liver span, anteroposterior diameter of the liver and portal vein, portal vein transverse diameter, caudate lobe anteroposterior diameter, and portal vein internal diameters as well as longitudinal liver scans in an aortic plane, sagittal plane, transverse plane, and kidney axis were measured. All measurements were analyzed according to age, sex, body mass index, obesity and alcohol consumption. The mean values of the age, height, weight and body mass index were calculated as 44.39 years, 167.05 cm, 74.23 kg, and 27.06kg/m2 in females, respectively. The same values were 44.13 years, 167.70 cm, 75.93 kg and 26.71 kg/m2 in males, respectively. There was significant difference between demographic characteristics, gender, and alcohol consumption in terms of anteroposterior diameter of the liver, portal vein transverse diameter of the right side and liver transverse scan. Also, some measurements including portal vein transverse diameter, liver transverse scan and at kidney axis longitudinal scan of liver showed significant difference between the age groups. There was significant difference in diagonal axis and anteroposterior diameter of liver, portal vein internal diameter, and longitudinal liver scans of the aortic plane parameters between obesity situation. The findings obtained will provide important and useful reference values as it may determine some abnormalities related liver diseases. Also, age, sex, obesity and body mass index values can be effective in the liver and portal vein morphometry related parameters.

El objetivo de este artículo fue realizar una evaluación de la morfometría del hígado y la vena porta mediante ecografía en una población turca sana. Este estudio se llevó a cabo en 189 sujetos (107 mujeres, 82 hombres). Se calcularon los datos demográficos y la superficie corporal. Se midió eleje longitudinal del de dos lóbulos del hígado, el eje diagonal o la extensión del hígado, los diámetros anteroposterior del hígado y de la vena porta, el diámetro transversal de la vena porta, anteroposterior del lóbulo caudado y los diámetros internos de la vena porta, así como las exploraciones longitudinales del hígado en un plano aórtico. Se midieron el plano sagital, el plano transversal y el eje del riñón. Todas las mediciones se analizaron según edad, sexo, índice de masa corporal, obesidad y consumo de alcohol. Los valores medios de edad, talla, peso e índice de masa corporal se calcularon como 44,39 años, 167,05 cm, 74,23 kg y 27,06 kg/m2 en las mujeres, respectivamente. Las mismas variable fueron 44,13 años, 167,70 cm, 75,93 kg y 26,71 kg/m2. Hubo diferencias significativas entre las características demográficas, el sexo y el consumo de alcohol en términos de diámetro anteroposterior del hígado, diámetro transversal de la vena porta del lado derecho y exploración transversal del hígado. Además, algunas mediciones, incluido el diámetro transversal de la vena porta, la exploración transversal del hígado y la exploración longitudinal del hígado en el eje del riñón, mostraron diferencias significativas entre los grupos de edad. Hubo diferencias significativas en el eje diagonal y el diámetro anteroposterior del hígado, el diámetro interno de la vena porta y los parámetros de las exploraciones hepáticas longitudinales del plano aórtico entre situaciones de obesidad. Los hallazgos obtenidos proporcionarán valores de referencia importantes y útiles ya que pueden determinar algunas anomalías relacionadas con enfermedades hepáticas. Además, los valores de edad, sexo, obesidad e índice de masa corporal pueden ser eficaces en los parámetros relacionados con la morfometría del hígado y la vena porta.

Liver Anatomy 2.0 Quiz: Test Your Knowledge.

The liver is one the largest organs in the abdomen and the most frequent site of metastases for gastrointestinal tumors. Surgery on this complex and highly vascularized organ can be associated with high morbidity even in experienced hands. A thorough understanding of liver anatomy is key to approaching liver surgery with confidence and preventing complications. The aim of this quiz is to provide an active learning tool for a comprehensive understanding of liver anatomy and its integration into clinical practice.

Current role of intraoperative ultrasonography in hepatectomy.

Hepatectomy had a high mortality rate in the previous decade because of inadequate techniques, intraoperative blood loss, liver function reserve misdiagnoses, and accompanying postoperative complications. However, the development of several modalities, including intraoperative ultrasonography (IOUS), has made hepatectomy safer. IOUS can provide real-time information regarding the tumor position and vascular anatomy of the portal and hepatic veins. Systematic subsegmentectomy, which leads to improved patient outcomes, can be performed by IOUS in open and laparoscopic hepatectomy. Although three-dimensional (3D) computed tomography and gadoxetic acid-enhanced magnetic resonance imaging have been widely used, IOUS and contrast-enhanced IOUS are important modalities for risk analyses and making decisions regarding resectability and operative procedures because of the vital anatomical information provided and high sensitivity for liver tumors, including "disappearing" liver metastases. Intraoperative color Doppler ultrasonography can be used to delineate the vascular anatomy and evaluate the blood flow volume and velocity in hepatectomy patients and recipients of deceased- and living-donor liver transplantation after vessel reconstruction and liver positioning. For liver surgeons, IOUS is an essential technique to perform highly curative hepatectomy safely, although recent advances have also been made in virtual modalities, such as real-time virtual sonography with 3D visualization.

Re-evaluation of the Couinaud classification for segmental anatomy of the right liver, with particular attention to the relevance of cranio-caudal boundaries.

BACKGROUND: Although the Couinaud classification of liver segments has been challenged by several studies, whether the cranio-caudal boundaries can be delineated in the right liver has not yet been assessed. This study scrutinized the third-order branching pattern of the portal vein in the right liver with attention to the validity of cranio-caudal segmentation. METHODS: Three-dimensional reconstruction of the portal vein and hepatic vein, using non-contrast-enhanced magnetic resonance imaging was performed in 50 healthy participants. RESULTS: In the right paramedian sector, the portal vein ramified into 2 thick P8s (P8vent and P8dor) in all the participants. Additional thick P8s that ran laterally and/or medially (P8lat and/or P8med) were observed in 18 (32%) participants. In contrast, multiple thin P5s, ranging in number from 2 to 6 (median, 4), branched from the right paramedian trunk, the right portal trunk, and/or even from P8s. In the right lateral sector, an arch-like type in which multiple P6s ramified from a single thick P7 was observed in 26 (52%) participants. A bifurcation type composed of a single P7 and a single P6 was observed in 23 (46%) participants, and a trifurcation type was observed in 1 participant. CONCLUSION: No clear cranio-caudal intersegmental plane could be delineated in the right liver in most of the participants. The resection of a whole Couinaud segment in the right liver should not be regarded as a systematic, anatomic resection from an oncologic viewpoint. In contrast, detailed information on the third-order portal vein ramification pattern is likely to be helpful when performing smaller anatomic resections.

[Research progress in the Hepatobiliary Surgery operation of hepatic hilar plate system].

An estimate of about 50% of new liver cancer cases worldwide occur in China every year.Surgical resection is still the major treatment choice for longer survival of patients with hepatocellular carcinoma. Blocking hepatic blood flow and reducing intraoperative bleeding ensure the success of the operation. Anatomic separation of hepatic hilar region is the precondition of hepatic inflow occlusion. The hepatic hilar plate system involves a thick layer of connective tissue covering the hepatic inflow ducts of hepatic hilar region. The descending part of hilar plate assists in reducing the anatomical difficulty of the hepatic hilar region. The "forth porta hepatis" that is hidden in the hepatic hilar plate system involves the accumulation area of "short hepatic portal veins" .The communicating branch vessels between the hepatic inflow vessels form the anatomical basis in reducing the indocyanine green fluorescence stain effect.The relatively fixed position of the hepatic portal plate is considered as a positioning marker for accurate liver resection. The intrahepatic Glisson sheath is connected with thick connective tissue of the hepatic portal panel system, and is regarded as the physical barrier in limiting the proliferation and hypertrophy of hepatocytes and continuation of hepatic portal panel system in the liver.This paper summarizes the anatomy and application of hepatic hilar plate system during hepatobiliary surgery.

Variations of the right branch of hepatic portal vein in children based on three-dimensional simulation technology.

PURPOSE: To study the variations of the right branch of the hepatic portal vein in children. METHODS: A total of 810 children's abdominal CT images were reconstructed with three-dimensional (3D) simulation software, Variations of the right branch of the hepatic portal vein were analyzed and classified. RESULTS: The most common anatomy (type A) was seen in 355 patients (43.83%). Trifurcation in the right anterior portal vein (type B) variation was seen in 250 cases (30.86%). The right posterior portal vein arched without obvious branching (type C) was seen in 71 cases (8.77%). There were 134 special variants (16.54%) named type D, including 14 cases (1.73%) with the right anterior branch in four sub-branches, 13 cases (1.60%) in one trunk and multiple sub-branches, 92 cases (11.36%) originating from the left trunk of the portal vein, and 15 cases (1.85%) with the VI segment of the portal vein originating from the right anterior branch of the portal vein. CONCLUSION: Variations in the right branch of the hepatic portal vein seems to be very frequent. Recognition of such variations is important in the preoperative evaluation of children with surgery planned, because these variations may have implications for anatomy-guided liver resection and for planning the operative approach.

[Surgical anatomy of the right portal vein]. / Khirurgicheskaia anatomiia vetvei vorotnoi veny pravoi doli pecheni.

OBJECTIVE: To study the features of surgical anatomy of intrahepatic segments of right portal vein. MATERIAL AND METHODS: The results of 260 histological examinations including sectional (n=60) and clinical (n=200) surveys were analyzed. Anatomical analysis implied assessment of organometric characteristics including liver weight, length, width and thickness of right and left lobes, division angles of portal vein, the number of branches, length and diameter of the vessels. Clinical examination was based on analysis of splenoportograms and X-ray direct portal venograms. Patients were divided into three groups according to their body type (dolichomorphic, mesomorphic, brachymorphic). RESULTS: Anatomical and clinical surveys confirmed the differences in metric characteristics of portal vascular system depending on the body type. There was medial angulation of the median fissure under 70-85º (78.0±3.4°) in dolichomorphic and mesomorphic patients. Right angle between the median fissure and lower liver surface was observed in brachymorphic subjects. Portal vein division into the branches of the first order to the right of the median fissure was found in 49 cases. Median or left-sided division was noted in other cases. In most cases (n=219), right portal vein dichotomously divided into the right paramedian and right lateral branches. Portal trifurcation was detected in 2.3% of cases, medial translocation of the right paramedian branch - in 1.1% of cases. CONCLUSION: Right liver lobe surgery may be associated with certain technical difficulties due to variable anatomy of the right portal vein. Anatomical and atypical liver resections should be preceded by preoperative identification of individual anatomical variations of the main liver vessels. Contrast-enhanced computed tomography is optimal method for this purpose.

The human liver: vascular anatomy to determine its segments and divisions / El hígado humano: anatomía vascular para determinar sus segmentos y divisiones

This study aims at understanding the vascularization of the human liver to determine the correct way to divide it into "divisions" (sectors) and segments, for which we dissected 250 livers using the acrylic resin injection method. The results showed the role of the "Porta hepatis" in the hepatic vascular distribution, the existence of seven vascular pedicles for seven portal segments, and the role of portal fissures in the parenchymal division of the liver. Our research provides the definition of a portal segment and demonstrates the role of the hepatic portal vein in originating any liver parenchymal division.

Quisimos estudiar la vascularización del hígado humano para determinar la forma correcta de dividirlo en "divisiones" y segmentos, para lo cual disecamos 250 hígados usando técnicas de inyección acrílica. Los resultados mostraron la función de la Porta hepatis en la distribución vascular del hígado, la existencia de siete pedículos vasculares para siete segmentos portales, y el rol de las fisuras portales en la división parenquimal del hígado. Ofrecemos la definición de lo que es un segmento portal y demostramos el rol de la vena porta hepática en originar cualquier división parenquimal del hígado.

New Technique for Management of Separate Right Posterior and Anterior Portal Veins in Pure 3D Laparoscopic Living Donor Right Hepatectomy.

BACKGROUND: Pure laparoscopic donor hepatectomy, including right hepatectomy, is being increasingly performed at experienced centers (Kim et al. Transplantation 101:1106-1110, 2017; Han et al. Medicine (Baltimore) 96:e8076, 2017; Suh et al. Am J Transplant 18:434-443, 2018; Hong et al. Br J Surg 105:751-759, 2018; Lee et al. Transplantation 102:1878-1884, 2018). However, anatomical variations in the portal vein remain major challenges and are regarded as contraindications by some centers. Using a stapler or clip in donors with these anatomical variations may result in kinking of the remnant portal vein due to the thick linear bite, as well as a reduction in the length of the graft portal vein. This report describes a liver donor with separate right posterior and anterior portal veins who underwent pure 3D laparoscopic donor right hepatectomy, focusing on a new technique of managing separate two portal veins. METHODS: A 45-year-old man offered to donate part of his liver to his father, who required a liver transplant for alcoholic liver cirrhosis. The father's Child-Pugh score was 7 and his Model for End-Stage Liver Disease score was 10.7. Donor height was 175.4 cm, body weight was 79.9 kg, and body mass index was 26.0 kg/m2. Preoperative computed tomography and magnetic resonance cholangiopancreatography showed that the donor had separate right posterior and anterior portal veins. Estimated graft-to-recipient weight ratio was 1.4% and remnant liver volume was 35.7%. The entire procedure was performed under 3D laparoscopic view using a flexible scope and real-time indocyanine green fluorescence cholangiography. The right posterior and anterior portal veins were divided using Hem-O-Lok clips. After retrieving the liver, the stumps of the portal veins were replaced with polypropylene sutures, followed by removal of the Hem-O-Lok clips (SNUH technique). RESULTS: The total operation time was 365 min, with no transfusion and no intraoperative complications. The portal veins were divided safely without any torsion or stricture. The stumps of the portal veins were sutured after retrieval of the liver graft, with suturing requiring about 12 min. The donor was discharged on postoperative day 7 with no complications. CONCLUSION: The SNUH technique, consisting of temporary clipping, intracorporeal suturing, and clip removal is safe and useful for pure laparoscopic right hepatectomy in donors with anatomic variations in the portal vein.

Study on the Segmentation of the Right Posterior Sector of the Liver.

BACKGROUND: The border between segments VI and VII of the right posterior sector of the liver is controversial owing to lack of anatomical landmarks. This study aimed to examine the segmentation of the right posterior sector. METHODS: Using three-dimensional software, ramification type of the right posterior portal vein (RPPV) was analysed in 100 patients. RESULTS: A bow-shaped anatomy, in which the RPPV exhibits a downward convex bow shape with several ramifications, was found in 50 patients. A bifurcation anatomy, in which the RPPV bifurcates into the cranial and caudal branches, was observed in 45 patients. In the bow-shaped anatomy, setting the segmentation was difficult due to lack of definite landmarks; thus, the downward portal branches were determined as segment VI branches, while horizontal and upward branches were determined as segment VII branches. In the bow-shaped anatomy, the incidence of full exposure of a thick branch of the right hepatic vein on virtual transection surface was 60.0%, while in the bifurcation anatomy, it was only 11.1%. No relations were observed between RPPV anatomy and main PV/right hepatic vein anatomy. The volumes of segments VI and VII were equal in both the bow-shaped and bifurcation anatomy. CONCLUSIONS: The bow-shaped and bifurcation types are commonly observed in RPPV anatomy. In the bifurcation anatomy, the right posterior sector is divided into segments VI and VII. In the bow-shaped anatomy, setting the segmentation was difficult, thus it may be compelled to be arbitrarily determined.

Allogeneic Venous Grafts of Different Origin Used for Portal Vein Reconstruction After Pancreaticoduodenectomy - Experimental Study.

BACKGROUND: In clinical medicine, little is known about the use of allografts for portal vein (PV) reconstruction after pancreaticoduodenectomy (PD). Portal and caval systems are physiologically different, therefore the properties of allografts from caval and portal systems were studied here in a pig model. MATERIALS AND METHODS: PD with PV reconstruction with allogeneic venous graft from PV or inferior vena cava (IVC) was performed in 26 pigs. Biochemical analysis and ultrasonography measurements were performed during a 4-week monitoring period. Computer simulations were used to evaluate haemodynamics in reconstructed PV and explanted allografts were histologically examined. RESULTS: The native PV and IVC grafts varied in histological structure but were able to adapt morphologically after transplantation. Computer simulation suggested PV grafts to be more susceptible to thrombosis development. Thrombosis of reconstructed PV occurred in four out of five cases in PV group. CONCLUSION: This study supports the use of allografts from caval system for PV reconstruction in clinical medicine when needed.

Prediction of Portal Vein Thrombosis Following Hepatectomy for Perihilar Cholangiocarcinoma: Efficacy of Postoperative Portal Vein Diameter Ratio and Angle.

BACKGROUND: Portal vein thrombosis (PVT) is a life-threatening complication after hepatectomy. However, the relationship between postoperative PVT and morphometric features of the PV has not been fully elucidated yet. PATIENTS AND METHODS: A total of 81 patients who underwent hepatectomy for perihilar cholangio-carcinoma (PHCC) were studied. We investigated the diameters and angles of PV using pre- and postoperative computed tomography (CT) reconstructed by SYNAPSE VINCENT®. RESULTS: The incidence of PVT after hepatectomy was 11.1%. There were significant differences with respect to the remnant liver PV diameter (p=0.015), the diameter ratio (p=0.001), and the postoperative PV angle (p=0.001) between patients with and without PVT. Multivariate analysis revealed that a postoperative PV angle of less than 90° (p=0.008) and a diameter ratio of less than 45% (p=0.041) were independent risk factors for PVT. CONCLUSION: A postoperative PV angle of less than 90° and diameter ratio of less than 45% eventually lead to PVT after hepatectomy for PHCC.

Laparoscopic donor right hepatectomy in a donor with type III portal vein anomaly: A case report.

RATIONALE: Laparoscopic right donor hepatectomy has been reported sporadically in several experienced centers for selected donors. This report introduced a case of a donor with an independent right posterior segmental portal branching from the main portal vein. PATIENT CONCERNS: A 47-year-old woman volunteered to donate her right liver to her 48-year-old husband. DIAGNOSES: The recipient has been diagnosed as hepatocellular carcinoma meeting the Milan criteria and hepatitis B virus related cirrhosis. INTERVENTIONS: The parenchymal transection was performed by ultrasonic aspirator and Hem-o-Lok clips. The right hepatic artery, right hepatic duct, and the anterior and posterior branches of right portal vein were meticulously dissected, clamped, and transected. The right hepatic vein was transected by vascular stapler. A Y-graft of the recipient's own portal confluence was reconstructed with the donor's separate right anterior and posterior portal veins. OUTCOMES: The donor's operation time was 420 minutes and the warm ischemia time was about 9 minutes. Blood loss was less than 600 ml without transfusion. The donor was discharged at the 10th postoperative day without any complications. LESSONS: Laparoscopic right hepatectomy for donors with anomalous portal vein branching and subsequent inflow reconstruction for adult living donor liver transplantation is safe and feasible in highly experienced center.

The types of connections between the portal sinus and main portal vein in foetuses / Tipos de conexiones entre el seno portal y la vena porta principal en fetos

In the prenatal period, the three types of connections between the portal sinus and main portal vein have been published in the literature: T, X and H-shaped. The T type is the most frequent in the literature, and the aim of our study is to define the percentage of the connection types during the prenatal period in our population. In this prospective study, 237 women between 20 and 38 weeks of pregnancy without a foetal anomaly or pregnancy-related complications were included, and the precordial veins of the foetuses were examined using a wide-band color Doppler technique. The types of connections were determined by two specialists according to the shape of the colour coded vessels in Doppler examinations. The criteria of Czubalski & Aleksandrowicz (2000) were used. All of the connection types in patients were confirmed using video clips and were stored in the picture archiving and communication system. In 237 patients, the types of connection were determined by the first specialist as 189 foetuses (79.7 %) with the X-shaped or side-to-side connection, 16 foetuses (6.8 %) with the T-shaped or end-to-side type and 32 foetuses (13.5 %) with the H-shaped or parallel-coursed vessels connected with a short segment. The most common types of connections between the portal sinus and main portal vein in foetuses are X shaped or side-to-side, which is contrary to previous studies.

En el período prenatal, se han publicado en la literatura los tres tipos de conexiones entre el seno portal y la vena porta principal: en forma de T, X y H. El tipo T es el más frecuente, y el objetivo de nuestro estudio fue definir el porcentaje de tipos de conexión durante el período prenatal en nuestra población. En este estudio prospectivo, se incluyeron 237 mujeres entre 20 y 38 semanas de embarazo, sin anomalías fetales o complicaciones relacionadas con el embarazo, y se examinaron las venas precordiales de los fetos utilizando una técnica Doppler de banda ancha. Los tipos de conexiones fueron determinados por dos especialistas según la forma de los vasos codificados por color en los exámenes Doppler. Se utilizaron los criterios del estudio de Czubalski & Aleksandrowicz. Todos los tipos de conexión en los pacientes se confirmaron mediante videoclips y se almacenaron en el sistema de comunicación y en archivo de imágenes. En 237 pacientes, el primer especialista determinó en 189 fetos (79,7 %) la conexión en forma de X o de lado a lado; en 16 fetos (6,8 %) la forma de T o Tipo de extremo a lado; y en 32 fetos (13,5 %) los vasos en forma de H o paralelos, conectados con un segmento corto. Los tipos más comunes de conexiones entre el seno portal y la vena porta principal en los fetos son en forma de X o de lado a lado, lo que es contrario a estudios anteriores.

Right intersectional transection plane based on portal inflow in left trisectionectomy.

PURPOSE: Left trisectionectomy (LT) extending to the segment I with bile duct resection for perihilar cholangiocarcinoma (PHC) is a technically demanding procedure with high morbidity. Liver transection during LT is generally conducted to expose the right hepatic vein (RHV) on the remnant side. In clinical practice, we have often encountered a discrepancy between the theoretical RHV-oriented plane and the actual right intersectional plane. METHODS: To enable anatomical LT safely, the three-dimensional right intersectional transection plane based on portal inflow was investigated using multidetector-row computed tomography, and it was compared to the theoretical RHV-oriented plane in 100 patients with hepatobiliary disease. RESULTS: The posterior portion of RHV just below the diaphragm was supplied by the dorsal portal branches of segment VIII in 85 cases of 100 (85.0%). The median volume of this portion was 82 mL (25-169 mL). On the other hand, the anterior region of the peripheral RHV was supplied by a few small ventral portal branches of segment VI in 24 of 90 cases (26.7%). The median volume of this portion was 53 mL (20-104 mL). In ten cases with a large inferior RHV, the RHV trunk was relatively short and did not reach the caudal part of the liver. CONCLUSIONS: The portal inflow-oriented right intersectional plane does not coincide with the RHV-oriented plane in most cases. The cranial part of the actual transection plane becomes hollow, whereas the caudal part is protruded in relation to the RHV. Hepatobiliary surgeons should recognize this complicated transection plane to avoid postoperative complications when performing LT for PHC.