Variations of hepatic veins: helical computerized tomography experience in 100 consecutive living liver donors with emphasis on right lobe

Adrenal Vein Sampling: Tips and Tricks

Adrenal vein sampling (AVS) is the standard method for distinguishing unilateral from bilateral sources of autonomous aldosterone production in patients with primary aldosteronism. This procedure has been performed at limited specialized centers due to its technical complexity. With recent advances in imaging technology and knowledge of adrenal vein anatomy in parallel with the development of adjunctive techniques, AVS has become easier to perform, even at nonspecialized centers. Although rare, anatomic variants of the adrenal veins can cause sampling failure or misinterpretation of the sampling results. The inferior accessory hepatic vein and the inferior emissary vein are useful anatomic landmarks for right adrenal vein cannulation, which is the most difficult and crucial step in AVS. Meticulous assessment of adrenal vein anatomy on multidetector CT images and the use of a catheter suitable for the anatomy are crucial for adrenal vein cannulation. Adjunctive techniques such as intraprocedural cortisol assay, cone-beam CT, and coaxial guidewire-catheter techniques are useful tools to confirm right adrenal vein cannulation or to troubleshoot difficult blood sampling. Interventional radiologists should be involved in interpreting the sampling results because technical factors may affect the results. In rare instances, bilateral adrenal suppression, in which aldosterone-to-cortisol ratios of both adrenal glands are lower than that of the inferior vena cava, can be encountered. Repeat sampling may be necessary in this situation. Collaboration with endocrinology and laboratory medicine services is of great importance to optimize the quality of the samples and for smooth and successful operation. ©RSNA, 2024 Test Your Knowledge questions for this article are available in the supplemental material.

Surgical Anatomy of the Liver-Significance in Ovarian Cancer Surgery

INTRODUCTION

Ovarian cancer is the leading cause of death among all gynecological malignancies. Most patients present with an advanced stage of the disease. The routes of spread in ovarian cancer include peritoneal dissemination, direct invasion, and lymphatic or hematogenous spread, with peritoneal and lymphatic spread being the most common among them. The flow direction of the peritoneal fluid makes the right subphrenic space a target site for peritoneal metastases, and the most frequently affected anatomical area in advanced cases is the right upper quadrant. Complete cytoreduction with no macroscopically visible disease is the most important prognostic factor.

METHODS

We reviewed published clinical anatomy reports associated with surgery of the liver in cases of advanced ovarian cancer.

RESULTS

The disease could disseminate anatomical areas, where complex surgery is required-Morrison's pouch, the liver surface, or porta hepatis. The aim of the present article is to emphasize and delineate the gross anatomy of the liver and its surgical application for oncogynecologists. Moreover, the association between the gross and microscopic anatomy of the liver is discussed. Additionally, the vascular supply and variations of the liver are clearly described.

CONCLUSIONS

Oncogynecologists performing liver mobilization, diaphragmatic stripping, and porta hepatis dissection must have a thorough knowledge of liver anatomy, including morphology, variations, functional status, potential diagnostic imaging mistakes, and anatomical limits of dissection.

Relationship of the Presence of the Inferior Right Hepatic Vein with the Right Hepatic Vein Diameter and CT Liver Volumetry

Background  Right hepatic venous anatomy, right lobe volume, and percentage of remnant liver are issues to be considered in preoperative planning especially transplantation. Objectives  The aim of this study was to investigate the relationship of the presence of the inferior right hepatic vein (IRHV) with the right hepatic vein (RHV) diameter, right lobe volume, and percentage of remnant liver. Materials and Methods  In t his cross-sectional study, the computed tomography (CT) images of 90 patients who underwent triphasic CT for being living liver donation were evaluated retrospectively. The number and diameter of IRHVs and the diameter of main RHV were recorded. For the liver volume analysis, a deep learning-based automatic liver segmentation (Hepatic VCAR) program was used. A virtual hepatectomy plane was drawn, where the right and left liver volumes were found and the percentage of the left lobe to the total liver volume was calculated. Pearson's correlation analysis was used for correlation analysis and Student's t -test was used to compare parameters. Results  A total of 74 IRHVs were detected in 53 (58.88%) of 90 patients. There were no differences in the percentage of remnant left lobe volume, right lobe volume, and RHV diameter between the IRHV (+) and (-) groups. The RHV diameter had a weak negative correlation with the IRHV diameter, and a weak positive correlation with the right lobe volume. Conclusions  The percentage of remnant left lobe volume, right lobe volume, and RHV diameter did not differ in liver donors with and without an IRHV. The RHV diameter had a weak negative correlation with the IRHV diameter and a weak positive correlation with the right lobe volume.

Surgical relevance of anatomic variations of the right hepatic vein

BACKGROUND

Variations in the anatomy of hepatic veins are of interest to transplant surgeons, interventional radiologists, and other medical practitioners who treat liver diseases. The drainage patterns of the right hepatic veins (RHVs) are particularly relevant to transplantation services.

AIM

The aim was to identify variations of the patterns of venous drainage from the right side of the liver. To the best of our knowledge, there have been no reports on RHV variations in in a Caribbean population.

METHODS

Two radiologists independently reviewed 230 contrast-enhanced computed tomography scans performed in 1 year at a hepatobiliary referral center. Venous outflow patterns were observed and RHV variants were described as: (1) Tributaries of the RHV; (2) Variations at the hepatocaval junction (HCJ); and (3) Accessory RHVs.

RESULTS

A total of 118 scans met the inclusion criteria. Only 39% of the scans found conventional anatomy of the main hepatic veins. Accessory RHVs were present 49.2% and included a well-defined inferior RHV draining segment VI (45%) and a middle RHV (4%). At the HCJ, 83 of the 118 (70.3%) had a superior RHV that received no tributaries within 1 cm of the junction (Nakamura and Tsuzuki type I). In 35 individuals (29.7%) there was a short superior RHV with at least one variant tributary. According to the Nakamura and Tsuzuki classification, there were 24 type II variants (20.3%), six type III variants (5.1%) and, five type IV variants (4.2%).

CONCLUSION

There was significant variation in RHV patterns in this population, each with important relevance to liver surgery. Interventional radiologists and hepatobiliary surgeons practicing in the Caribbean must be cognizant of these differences in order to minimize morbidity during invasive procedures.

The role of intraoperative ultrasonography in detection of hepatic vein variations in living donor liver transplantation

BACKGROUND

With advances in surgical techniques and immunosuppression, liver transplantation has become the most effective treatment of acute and chronic liver failures. Evaluation of vascular anatomy and detection of hepatic vascular variations prior to surgery, especially transplantation surgery, can help reduce complications in both the donor and the recipient. Intraoperative ultrasonography (IOUS) is known to be beneficial during planning of the transplantation surgery, and can help direct the surgery itself.

OBJECTIVES

To our knowledge, there are no existing studies that evaluate the number and diameter of segment 5 and 8 branches that need to be anastomosed with IOUS.

PATIENTS AND METHODS

In this study, considering surgical anatomical evaluation as the gold standard, IOUS findings were compared to computed tomography angiography (CTA) findings. 40 patients were included in the study.

RESULTS

The average diameters of segment 8 branches that were anastomosed and not anastomosed were significantly different when measured by IOUS (p = 0.016); however, no such statistically significant difference was found in measurements made with CTA (p = 0.89).

CONCLUSION

CTA is superior to IOUS in detecting segment 5 and 8 veins draining into the middle hepatic vein. However, IOUS is more accurate in predicting which vessels are going to be anastomosed. For a complete and accurate assessment, both imaging modalities should be used to complement each other, and their respective advantages and disadvantages should be known.

Gallbladder necrosis and small bowel ischaemia following fenestrated endovascular aneurysm repair for juxtarenal abdominal aortic aneurysm: a case report

Anatomical variation may result in unexpected complications after fenestrated endovascular aneurysm repair (FEVAR). We report a 78-year-old gentleman who was admitted for elective FEVAR procedure for a juxtarenal abdominal aortic aneurysm. Three days post-operatively, he deteriorated clinically. Computed tomography (CT) angiogram showed small bowel ischaemia and a replaced right hepatic artery originating from superior mesenteric artery. A necrotic gallbladder found during laparotomy required cholecystectomy following small bowel resection that required a relook for anastomosis and drainage of bile collection. He had prolonged ICU stay requiring treatment for multiple organ dysfunction then spent 4 weeks in hospital. Following multidisciplinary team approach in management of his complications during post-operative phase, he recovered well enough for rehabilitation and discharge home. Surveillance CT aorta at 1 month and 6 months post FEVAR showed satisfactory FEVAR appearance with no endoleak.

Inferior right hepatic vein on routine contrast-enhanced CT of the abdomen: prevalence and correlation with right hepatic vein size

AIM

To determine the prevalence of the inferior right hepatic vein (IRHV) in patients undergoing routine contrast-enhanced computed tomography (CECT) of the abdomen and to compare it with the size of the right hepatic vein (RHV).

MATERIALS AND METHODS

Two hundred and twenty-four consecutive patients who underwent routine CECT abdomen, with adequate venous opacification, were included in the study. The number and diameter of IRHVs and the diameter of the RHV was noted in each case.

RESULTS

A total of 214 IRHVs were detected in 126 cases (56.2%) with a mean diameter of 4.15±1.44 mm. The number of IRHVs ranged from one to four (more than one IRHV was present in 39.7% [50/126] of cases). In approximately one-third of cases (46/126), an IRHV ≥5 mm was found. A weak negative correlation was found between size of the RHV and IRHV (Pearson's correlation coefficient -0.222; p=0.01). The RHV was smaller in size in patients with an IRHV (7.34±1.88 mm) than in patients without an IRHV (8.47±1.99 mm) on CECT abdomen. A larger IRHV was associated with a smaller RHV (6.91±2.05 mm).

CONCLUSION

The presence of IRHV on routine CECT abdomen is frequent, and it is not uncommon to encounter more than one IRHV. The diameter of the IRHV has a weak negative correlation with the diameter of the RHV, and a smaller RHV is found in patients with an IRHV.

3D Reconstruction and Evaluation of Accessory Hepatic Veins in Right Hemilivers in Laboratory Animals by Metrotomography: Implications for Surgery

Background

The current study investigated the detection of accessory hepatic veins and their vascular territories in the right hemiliver in rats, guinea pigs, and rabbits, which has become a prerequisite for newly developed clinical procedures. We compared the anatomical continuity of accessory hepatic veins with accessory hepatic veins existing in human livers.

Material/Methods

The analysis of accessory hepatic veins was performed using a corrosion cast method in combination with computer tomography (CT).

Results

In normal livers, accessory hepatic veins were regularly found. The length of these veins was 0.88±0.29 (cm ±SD) in rats, 1.10±0.39 in guinea pigs, and 1.28±0.48 in rabbits. Accessory hepatic veins became a part of the draining vessel draining into segment VI and VII; represented by interpolating and following Chouinard’s segmental concept.

Conclusions

The importance of detecting accessory hepatic veins lies in the identification of structures requiring special attention during surgery, in reduction of surgical complications, and in choosing the best approach to maintain the vitality of a drainage segment. The vascular reconstruction should be done during surgical interventions.

Evaluation of Numerical and Positional Variations of the Hepatic Veins: A Cadaveric Study

INTRODUCTION

Hepatic veins are the major linking vessels between systemic and portal circulation. Numerical and positional variation of the hepatic veins can play a significant role during surgical interventions on the liver.

MATERIALS AND METHODS

Gross anatomical study regarding the number and arrangement pattern of hepatic veins was undertaken on 88 adult livers which were stored in 10% formalin after the regular dissection classes.

RESULT

Six livers (7%) were found to be drained only by major hepatic veins, whereas 82 out of 88 livers (93%) had accessory (minor) hepatic veins. The total number of persistent hepatic veins ranged from 2 to 10 with the highest prevalence of four hepatic veins (35.2%) followed by 5 (19.3%) and 6 (17%). The presence of three major veins was seen in 45 (51%) livers while 41 (47%) livers had two major hepatic veins. Remaining two livers (2%) showed the presence of four major hepatic veins. In 95% specimens, the minor hepatic veins entered the inferior vena cava below the level of entry of major veins. In 2.5% cases, their entry point was above the major veins and in 2.5% cases, the entry point was below major veins.

CONCLUSION

The data resulting from this study provides a clear idea about the number and drainage pattern of the hepatic veins into the liver. Knowledge of numerical and positional variations of hepatic veins could be useful in normal Doppler ultrasound hepatic vein flow velocities and their variation with respiration in healthy adults as comparable with the similar approach of superior vena cava.

Liver transplantation in a patient with complex anomaly of the inferior vena cava

BACKGROUND

After the introduction of noninvasive imaging exams, congenital anomalies of the inferior vena cava (IVC) have become more commonly recognized. We report the first successful orthotopic liver transplantation (OLT) performed in an asymptomatic adult with complex IVC anomaly: duplication of the infrarenal IVC, azygos continuation of the IVC, agenesia of the hepatic portion of the IVC and presence of several anomalous veins communicating the common iliac vein and the IVC of one side with the contralateral side.

METHODS

This complex anomaly was diagnosed with a venous abdominal angio CT.

RESULTS

At liver transplantation, the short suprahepatic portion of the IVC was identified and clamped. The right, middle, and left hepatic veins were sectioned and joined in a single, wide cuff, using venoplasty. This single orifice was anastomosed to the suprahepatic IVC of the new liver. No venovenous bypass was employed. The patient had an uneventful postoperative course. A post transplantation venous abdominal angio CT showed normal blood flow at the anastomosis of the hepatic veins of the receptor and the IVC of the new liver.

CONCLUSIONS

This report is important to alert liver transplant teams of the possibility of complex IVC in asymptomatic adult individuals. Identification of these anatomical anomalies is vital to reduce the risk of serious hemorrhage and other operative complications during OLT.

3D imaging-guided individualized hepatic vein typing: Application to liver tumor resection

AIM: To conduct 3D imaging-guided individualized typing of hepatic veins to provide a basis for digitalized liver segment resection.

METHODS: Fifty hospitalized liver cancer patients who underwent 64-row spiral CT preoperatively were included. 3D reconstruction of the liver was performed to observe the variation of reconstructed hepatic veins and typing them.

RESULTS: Hepatic veins were overall classified into two types: A (27/50, 54%) and B (23/50, 46%). The right hepatic vein were classified into four types: A: (36/50, 72%), B (10/50, 20%), C (2/50, 4%), and D (2/50, 4%). The right hepatic vein was classified into four subtypes: I (17/50, 34%), II (28/50, 56%), III (3/50, 6%), and IV (4/50, 8%). The middle hepatic vein was classified into three types: A (39/50, 78%), B (10/50, 20%), and C (1/50, 2%). The left hepatic vein was classified into two types: A (41/50, 82%) and B (9/50, 18%).

CONCLUSION: 3D imaging-guided individualized hepatic vein typing can help retain more normal liver tissue and reduce the occurrence of postoperative complications in liver surgery.

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.

Living-donor liver transplant using the right hepatic lobe without the right hepatic vein: solving the drainage problem

Although rare, major congenital defects of the hepatic veins are detectable at autopsy, advanced, noninvasive imaging techniques such as Doppler ultrasonography and multislice computed tomography can accurately define these anomalies. One of these anomalies is congenital absence of the main right hepatic vein. We present a 21-year-old woman living-liver donor candidate with congenital absence of the right hepatic vein who underwent an extended right donor hepatectomy. She was tested for transplant compatibility with her 45-year-old brother, who had chronic liver failure secondary to hepatitis B. Multislice computed tomography revealed an absence of the right hepatic vein, and the right hepatic lobe was drained by 4 inferior hepatic veins with diameters ranging from 4 to 8.4 mm. An extended right-donor hepatectomy was performed. A common-large opening drainage reconstruction model that included all of the inferior hepatic veins and middle hepatic vein was created using the saphenous vein and an aortic homograft. There were no postoperative complications related to hepatic venous drainage thanks to the common-large opening model. We demonstrate that a right donor hepatectomy is feasible in congenital absence of the right hepatic vein solving the drainage problem using common-large opening reconstruction technique.

Anatomical variations of hepatic veins: three-dimensional computed tomography scans of 200 subjects

BACKGROUND

The impact of hepatic venous anatomic variations on hepatic resection and transplantation is the least understood aspect of liver surgery.

METHODS

A prospective three-dimensional computed tomography study was undertaken on 200 consecutive subjects with normal livers to determine the prevalence of surgically significant hepatic venous anatomic variations.

RESULTS

The prevailing pattern of the three hepatic veins in these subjects was a right hepatic vein (RHV) and a common trunk for the middle (MHV) and left (LHV) hepatic veins (122/200, 61%). The remaining patients had the RHV, MHV, and LHV draining independently into the inferior vena cava (IVC). In 39% of patients, the RHV was small and was compensated by a large right inferior hepatic vein (21.0%), an accessory RHV (8.5%) or a well-developed MHV (6.5%). A segment 4 vein was seen in 51.5% of patients. This segment 4 vein joined the LHV (26%), the MHV (17.5%), or the IVC (8%). An umbilical vein and a segment 4 vein were seen in 3.5% of patients. These two veins joined either the LHV (2.0%) or the MHV (1.5%).

CONCLUSIONS

Knowing the variations of hepatic veins before surgery is useful during both partial hepatectomy and donor operations for living related liver transplantation.

The results of vascular and biliary variations in turks liver donors: comparison with others

Objective. To evaluate liver anatomy with a view to access unerring surgery in liver donors. Summary Background Data. Liver transplantation, the unique curative treatment option for end-stage hepatic failure, has become routinely practicable, which was inconceivable in the past. But, the vascular and biliary anatomy of the liver has not been completely disclosed yet. Methods. From 1994 to 2009, we have done a research on 496 liver donors. The data were accumulated and categorized according to the most widely used classification systems. Results. Of 496 liver donors, 393 (79.1%) underwent the right donor hepatectomy, 98 (19.9%) were performed the left lateral segmentectomy, and 5 donors (1%) underwent the left donor hepatectomy surgery. Given the data regarding to 398 liver donors undergone right and left donor hepatectomy, arteries, bile ducts, and portal vein showed classical anatomy in 107 (21.6%) donors. Variations in all three systems were found in 16 donors (3.2%). In the remaining 275 donors (75.2%), anatomical variations were found at either of arterial, biliary, or portal system. Conclusions. Our study could come up to actual estimate in liver anatomy as any of donors have not been removed in our institute due to high hilar dissection technique.

Persistence of embryonic pattern of hepatocaval venous junction and patent ductus venosus in Budd-Chiari syndrome

We report an autopsy study on a case of Budd-Chiari syndrome (BCS) in a 44-year-old woman. Dissection showed that the outlets of the right hepatic vein (HV) and of the common trunk of the middle and left HVs appeared as two small depressed areas with narrow ostia. Histological examination showed recent thrombosis of the tributaries of the HVs and centrilobular congestion with necrosis of the hepatic parenchyma. The juxtacaval portions of the major HVs showed a cuneiform shape, because of marked dilation, with thread-like ostia, and multiple small outlets of minor hepatic veins were also present. The coexistence of patent ductus venosus may have prevented the development of the hepatocaval venous junction, with persistence of the embryonic pattern, composed of multiple small channels draining into the right hepatocardiac channel. The unusual hepatocaval venous junction may have predisposed to thrombosis of the HVs, causing BCS.

Branching patterns and drainage territories of the middle hepatic vein in computer-simulated right living-donor hepatectomies

Full right hepatic grafts are most frequently used for adult-to-adult living donor liver transplantation (LDLT). One of the major problems is venous drainage of segments 5 and 8. Thus, this study was designed to provide information on venous drainage of right liver lobes for operation-planning. Fifty-six CT data sets from routine clinical imaging were evaluated retrospectively using a liver operation-planning system. We defined and analyzed venous drainage segments and the impact of anatomic variations of the middle hepatic vein (MHV) on venous outflow from segments 5 and 8. MHV variations led to significant shifts of segment 5 drainage between the middle and right hepatic vein. In cases with the most frequent MHV branching pattern (n = 33), a virtual hepatectomy closely right to the MHV intersected drainage vessels that provided drainage for 30% of the potential graft, not taking into account potential veno-venous shunts. In individuals with inferior MHV branches that extend far into segments 5 and 6 (n = 10), the overall graft volume at risk of impaired venous drainage increased by 5% (p < 0.001). If this is confirmed in clinical trials and correlated with intraoperative findings, the use of liver operation-planning systems would be beneficial to improve overall outcome after right lobe LDLT.