Imaging of Hepatic Arterial Anatomy for Depicting Vascular Variations in Living Related Liver Transplant Donor Candidates With Multidetector Computed Tomography: Comparison With Conventional Angiography

Radiological assessment of secondary biliary tree lesions: an update

Objective

To conduct a systematic literature review of imaging techniques and findings in patients with peribiliary liver metastasis.

Methods

Several electronic datasets were searched from January 1990 to June 2017 to identify studies assessing the use of different imaging techniques for the detection and staging of peribiliary metastases.

Results

The search identified 44 studies, of which six met the inclusion criteria and were included in the systematic review. Multidetector computed tomography (MDCT) is the technique of choice in the preoperative setting and during the follow-up of patients with liver tumors. However, the diagnostic performance of MDCT for the assessment of biliary tree neoplasms was low compared with magnetic resonance imaging (MRI). Ultrasound (US), without and with contrast enhancement (CEUS), is commonly employed as a first-line tool for evaluating focal liver lesions; however, the sensitivity and specificity of US and CEUS for both the detection and characterization are related to operator expertise and patient suitability. MRI has thus become the gold standard technique because of its ability to provide morphologic and functional data. MRI showed the best diagnostic performance for the detection of peribiliary metastases.

Conclusions

MRI should be considered the gold standard technique for the radiological assessment of secondary biliary tree lesions.

Comparative analysis of three-dimensional volume rendering and maximum intensity projection for preoperative planning in liver cancer

Three-dimensional imaging is a useful tool to evaluate liver structure and surrounding vessels for preoperative planning. In this study, we compared two methods of visualizing vascular maps on computed tomography including maximum intensity projection (MIP) and 3D volume rendered (VR) imaging. We compiled important imaging components of pre-surgical planning, and developed criteria for comparison. The imaging techniques were compared based on colorization, volume quantification, rotation, vessel delineation, small vessel clarity, and segmental liver isolation. MIP had more overall limitations due to reduced differentiation of superimposed structures, motion artifact, and interference from calcifications. We determined that because 3D quantitative volume rendered imaging can provide more detail and perspective than MIP imaging, it may be more useful in preoperative planning for patients with liver malignancy. Advanced 3D imaging is a useful tool that can have profound clinical implications on cancer detection and surgical planning.

Aberrant left hepatic arteries arising from left gastric arteries and their clinical importance

BACKGROUND

The Aberrant Left Hepatic Artery (ALHA) is replaced when it does not originate from the hepatic artery proper and it is the only supply to that part of the liver, while an accessory artery coexists with a normal artery. The aim of this systematic review is to evaluate the incidence of ALHAs including the one arising from the Left Gastric Artery, also named Hyrtl's artery.

METHODS

A literature search in PubMed, SCOPUS, WOS and Google Scholar was performed. The risk of bias was assessed by means of the AQUA tool. The main outcome was the prevalence of ALHA. Secondary outcomes were the prevalence of the accessory and replaced left hepatic arteries. A subgroup analysis was conducted by geographic region and type of evaluation.

RESULTS

This review included 57 studies, with a total of 19,284 patients. The majority of the studies involved the use of radiological techniques -especially Angio-CT-and were performed in Asia. The overall risk of bias was moderate. The overall prevalence of the ALHA was 13.52%; the overall prevalence was 8.26% for the Replaced ALHA and 5.55% for the Accessory ALHA. In the 18 studies that employed Michels' classification, Type II had the lowest prevalence (0.36%) and Type VII the highest prevalence (6.62%).

DISCUSSION

Some of the studies included did not distinguish between the ''replaced'' and ''accessory'' ALHA (34.25%). Some surgical dissection techniques proved insufficient for the localization of other hepatic arteries. These results suggest that an accurate preoperative radiological evaluation is needed to localize replaced arteries.

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.

Surgical Anatomy of the Superior Mesenteric Vessels Related to Pancreaticoduodenectomy: a Systematic Review and Meta-Analysis

BACKGROUND AND PURPOSE

Mesopancreas dissection with central vascular ligation and the superior mesenteric artery (SMA)-first approach represent the cornerstone of current principles for radical resection for pancreatic head cancer. The surgeon dissecting around the SMV and SMA should be aware regarding the anatomical variants in this area. The aims of this systematic review and meta-analysis are to detail the surgical anatomy of the superior mesenteric vessels and to propose a standardized terminology with impact in pancreatic cancer surgery.

METHODS

We conducted a systematic search to identify all published studies in PubMed/MEDLINE and Google Scholar databases from their inception up to March 2017.

RESULTS

Seventy-eight studies, involving a total of 18,369 specimens, were included. The prevalence of the mesenteric-celiac trunk, replaced/accessory right hepatic artery (RRHA), common hepatic artery, and SMV inversion was 2.8, 13.2, 2.6, and 4.1%, respectively. The inferior pancreaticoduodenal artery has its origin into the first jejunal artery, SMA, and RRHA, in 58.7, 35.8, and 1.2% of cases, respectively. The SMV lacks a common trunk in 7.5% of cases. The first jejunal vein has a trajectory posterior to the SMA in 71.8% of cases. The left gastric vein drains into the portal vein in 58%, in splenic vein (SV) in 35.6%, and into the SV-PV confluence in 5.8% of cases.

CONCLUSIONS

Complex pancreaticoduodenal resections require detailed knowledge of the superior mesenteric artery and vein, which is significantly different from the one presented in the classical textbooks of surgery. We are proposing the concept of the first jejunopancreatic vein which impacts the current oncological principles of pancreatic head cancer resection.

The Main Anatomic Variations of the Hepatic Artery and Their Importance in Surgical Practice: Review of the Literature

Anatomical variations of the hepatic artery are important in the planning and performance of abdominal surgical procedures. Normal hepatic anatomy occurs in approximately 80% of cases, for the remaining 20% multiple variations have been described. The purpose of this study was to review the existing literature on the hepatic anatomy and to stress out its importance in surgical practice. Two main databases were searched for eligible articles during the period 2000 - 2015, and results concerning more than 19,000 patients were included in the study. The most common variation was the replaced right hepatic artery (type III according to Michels classification) which is the chief source of blood supply to the bile duct.

[Living liver donor: indications and technical aspects]

Living donor liver transplantation (LDLT) nowadays represents an important and safe alternative to conventional deceased donor liver transplantation (DDLT). A major concern related to the LDLT procedure is still represented by donor safety because a serious operation not without risks must be carried out on a healthy individual. In the present review of the indications for LDLT the technical concepts of donor surgery, criteria for donor selection and evaluation and morbidity and mortality results related to the procedure are presented. In general, the indications for LDLT are almost the same as for DDLT. The donor hepatectomy (right, left or left lateral) is presented in five main phases. The reported morbidity rates vary between 10 % and 60 % and are strongly related to the experience of the transplant center. The currently reported postoperative mortality rates for left and right hepatectomy are 0.1 % and 0.5 %, respectively. The results of LDLT are similar if not even better than those for DDLT depending on the specific indications.

Right hepatic artery from splenic artery: the four-leaf clover of hepatic surgery

The anatomy of hepatic arteries is one of the most variable. Accurate awareness of all the possible anatomic variations is crucial in the upper GI surgery and especially in liver and pancreas transplantation. The most frequent anatomical variants are: a replaced or accessory right hepatic artery (RHA) from the superior mesenteric artery (6.3-21 %), a replaced or accessory left hepatic artery (LHA) from the left gastric artery (LGA) (3-18 %) or a combination of these two variants (up to 7.4 %). Herein, we describe the case of a 67-year-old cadaveric organ donor who presented a RHA originating from the splenic artery (SA) associated with both a CHA originating from the celiac trunk (CT) and a LHA originating from the LGA.

Clinically relevant anatomical parameters of the replaced right hepatic artery (RRHA)

PURPOSE

Vascular anatomy of the liver is subjected to many variations. The most common hepatic artery (HA) replacement is the right hepatic artery (RRHA). Variations of the HA are particularly important consideration when choosing the best surgical procedure or if radiological abdominal intervention is required. In this study, we evaluated the anatomical details of the RRHA origin.

METHODS

Retrospective investigation of clinical data from 1569 patients who underwent an abdominal MDCT was performed. The anatomy of RRHA origin was described based on four parameters measured: D--the distance between SMA origin and the RRHA origin, L--the lumen at the place of origin, AH--the origin angle from the SMA in horizontal plane, and AV--the origin angle from the SMA in vertical plane.

RESULTS

RRHA arising from SMA was detected in 10.13 % of cases (159/1569) and its anatomy was subjected to variations. Mean (±SD) of parameters D, L, AH and AV was 27.34 mm ± 6.83, 3.29 mm ± 1.17, 97.27º ± 26.69 and 89.73º ± 20.81, respectively. Values of parameters D and L were significantly higher in males compared to females.

CONCLUSION

Although radiologists are not always aware of the clinical significance of the RRHA origin, the evaluation of its anatomy is thought to help reduce the risk of inadvertent vascular injury, especially in pancreatoduodenectomy. Detection and evaluation of the RRHA does not necessarily require angio-CT examination. Our study demonstrated that the MDCT, the standard imaging modality for diagnosing the abdominal symptoms, is sufficient to provide the knowledge of the HA abnormalities.

Visualization of the segment IV hepatic artery using 128-section MDCT angiography

AIM

To visualize the segment IV hepatic artery and to evaluate the variations in anatomy using multidetector computed tomography (MDCT) angiography.

MATERIALS AND METHODS

Six hundred and seventeen patients (381 men and 236 women; mean age 62.7 ± 8.1 years; age range 22-92 years) who underwent MDCT angiography performed using a 128-section MDCT system were included in the study. The segment IV hepatic arteries of 453 patients with adequate image quality were displayed using volume rendering (VR), maximum intensity projection (MIP), and multiplanar reconstruction (MPR), and were analysed regarding the origination and variation of the arteries by two radiologists and an anatomist retrospectively.

RESULTS

Segment IV arteries were categorized into five different types according to their points of origin: left hepatic artery (LHA, 51.66%), right hepatic artery (RHA, 30.68%), proper hepatic artery (PHA, 5.3%), dual (12.14%), and triple (0.22%). Segment IV arteries arising from normal LHA, RHA, and PHA were found in 73.73% of patients, and those arising from variant LHA or RHA were found in 26.27%. The patterns RN2, LA2, LA3, LA4, PN2, PV1, DA1, DA2, DV3, and DV4 were first reported in the present study.

CONCLUSIONS

MDCT angiography can evaluate normal as well as anatomical variants of segment IV arteries. Predicting arterial patterns of segment IV of the liver is important in planning and performing all radiological and surgical procedures in the liver, especially in hemi-liver graft procedures.

Are the imaging findings used to assess the portal triad reliable to perform living-donor liver transplant?

BACKGROUND

A crucial aspect of living-donor liver transplant is the risk imposed to the donor due to a procedure performed in a healthy individual that can lead to a high postoperative morbidity rate

AIM

To correlate the pre- and intraoperative hepatic imaging findings of living adult donors.

METHODS

From 2003 to 2008 the medical charts of 66 donors were revised; in that, 42 were males (64%) and 24 females (36%), mean age of 30 ± 8 years. The preoperative anatomy was analyzed by magnetic resonance cholangiography to study the bile ducts and by computed tomography angiography to evaluate the hepatic artery and portal vein. Normalcy criteria were established according to previously published studies.

RESULTS

Anatomic variations of the bile ducts were found in 59.1% of donors, of the artery hepatic in 31.8% and of the portal vein in 30.3% of the cases during the preoperative period. The magnetic resonance cholangiography findings were in agreement in 44 (66.6%) of donors and in disagreement in 22 (33.3%). With regards to hepatic artery, in all donors the findings of the imaging examination were in agreement with those of the intraoperative period. As to the portal vein, the computed tomography findings were in agreement in 59 (89.4%) donors and in disagreement in seven (10.6%).

CONCLUSIONS

The bile duct anatomic variations are frequent, and the magnetic resonance cholangiography showed moderate accuracy (70%) in reproducing the surgical findings; the computed tomography reproduced the intraoperative findings of the hepatic artery in 100% of donors, and of the portal vein in 89.4% of the cases, thus demonstrating high accuracy (89%).

Sixty-four-slice computed tomography angiography of perigastric veins with image fusion

OBJECTIVE

The objective of this study was to assess the efficacy and clinical value of 64-slice computed tomography angiography (CTA) with image fusion for demonstrating the perigastric venous anatomy.

METHODS

Twenty-six patients with gastric cancer underwent abdominal CTA examinations. Computed tomography angiography of stomach and perigastric veins and arteries were reconstructed and fused using volume-rendering technique. The inflow and courses of perigastric veins as well as the spatial relationship among the perigastric veins, arteries, and stomach were compared with surgery.

RESULTS

Compared with surgical findings, the visualization rate of the 7 perigastric veins on CTA was 90.9% to 100%. There was a statistically significant decrease in number of short gastric veins identified on CTA compared with surgery (P = 0.004). There was no statistically significant difference between the 2 modalities in detecting other perigastric veins including the left gastric vein, right gastric vein, right gastroepiploic vein, left gastroepiploic vein, posterior gastric vein, and gastrocolic trunk (P = 0.317, P = 0.157, P = 1, P = 1, P = 0.317, P = 1, respectively).

CONCLUSIONS

Sixty-four-slice CTA with image fusion clearly depicts most of perigastric veins and their relationship with the stomach and perigastric arteries. It can facilitate gastrectomy.

Ectopic blood supply of hepatocellular carcinoma as depicted by angiography with computed tomography: associations with morphological features and therapeutic history

OBJECTIVE

To investigate the associations of ectopic blood supply of hepatocellular carcinoma (HCC) with its morphological features and therapeutic history.

METHODS

Three hundred and six patients with 373 HCC lesions were enrolled in this study, and underwent biphasic contrast-enhanced scans on a 64-section MDCT. The anatomy of ectopic blood supply, morphological characteristics of HCC including the size, location and pseudocapsule, and history of transcatheter arterial chemoembolization (TACE) therapy were quantitively assessed and statistically analyzed.

RESULTS

Ectopic blood supply was found in 30.8% (115/373) lesions. The ectopic arteries were predominantly composed of inferior phrenic artery (86/115) followed by left and right gastric artery (25/115). Tumor size, location, status of pseudocapsule, and history of TACE therapy could impact the origination of ectopic arteries (all p<0.05).

CONCLUSION

The ectopic feeding arteries of HCC predominantly composed of the perihepatic arteries are associated with the morphological features of the tumor and therapeutic history.

Multidetector computed tomographic angiography evaluation of micropig major systemic vessels for xenotransplantation

Due primarily to the increasing shortage of allogeneic donor organs, xenotransplantation has become the focus of a growing field of research. Currently, micropigs are the most suitable donor animal for humans. However, no standard method has been developed to evaluate the systemic vascular anatomy of micropigs and standard reference values to aid in the selection of normal healthy animals as potential organ donors are lacking. Using 64-channel multidetector row computed tomographic angiography (MDCTA), we evaluated morphological features of the major systemic vessels in micropigs and compared our results to published human data. The main vasculature of the animals was similar to that of humans, except for the iliac arterial system. However, diameters of the major systemic vessels were significantly different between micropigs and humans. Specifically, the diameter of the aortic arch, abdominal aorta, external iliac artery, and femoral artery, were measured as 1.50 ± 0.07 cm, 0.85 ± 0.06 cm, 0.52 ± 0.05 cm, and 0.48 ± 0.05 cm, respectively, in the micropigs. This MDCTA data for micropig major systemic vessels can be used as standard reference values for xenotransplantation studies. The use of 64-channel MDCTA enables accurate evaluation of the major systemic vasculature in micropigs.

Ultrasound examination of the liver: Variations in the vascular anatomy

The hepatic vasculature is highly complex. The hepatic artery (a branch of the celiac tripod) and the portal vein (formed by the confluence of the splenic and superior mesenteric veins) provide a dual blood supply while venous drainage is guaranteed by the hepatic veins. There are also numerous anatomic variants that can involve one or more of the system's three components.Hepatic artery variants are the least common. Ten types have been identified, including several that are fairly frequent and others that are quite rare, and the variation generally involves the extrahepatic portion of the vessel. Portal vein variants are found in around 20% of the population. They can involve the main portal trunk or segmental branches. Variants of the hepatic veins are the most common. They involve the number and course (supernumerary veins) or the number, course, and openings (accessory veins).Knowledge of portal vein and hepatic vein variants, which are extremely common, is of prime importance for precise localization of lesions. Hepatic artery variants are equally important for surgical treatment of hepatic disease, especially liver transplantation, where it is essential for preoperative workup and postoperative follow-up of the recipient as well as for assessment of potential donors.

Sonographic anatomy of the gastrohepatic ligament

OBJECTIVE

The purpose of this presentation is to illustrate anatomic and pathologic features of the gastrohepatic ligament (GHL) and to show its usefulness for precise localization of abnormalities, particularly in relation to the lesser peritoneal cavity and diseases occurring within the confines of the ligament itself.

METHODS

Cases were selected that illustrate the objectives above.

RESULTS

Illustrations show various anatomic and pathologic features meant to enhance interpretation of left upper quadrant sonograms.

CONCLUSIONS

Illustrations seen in the sonographic literature vaguely interpret the relationships of the GHL. Misunderstanding has led not only to improper nomenclature but also to the use of inappropriate indicators of lesser omental diseases. With a clear understanding of the anatomy of the GHL and its use as a pivotal marker for structures around and within it, one can avoid these pitfalls and better evaluate adult and pediatric lesser omental anatomy.

Hepatic arterial mapping by multidetector computed tomographic angiography in living donor liver transplantation

PURPOSE

Our aims were to present the hepatic arterial variations that were detected with computed tomographic angiography (CTA) and confirmed by operation in living liver donors and to emphasize the usefulness of CTA in the assessment of hepatic arterial anatomy.

MATERIALS AND METHODS

The donors of 100 patients (46 women and 54 men) who had undergone a living donor liver transplantation in a (blinded) hospital between July 2004 and June 2007 were evaluated. The age of the donors ranged from 18 to 63 years (mean, 39 years). The CTA images obtained by a 16-slice multidetector CT before the transplantation procedure were retrospectively evaluated for arterial variations, and the results were compared with the results of the operation.

RESULTS

In 59 donors (59%), classic hepatic arterial anatomy was observed. In the remaining 41 donors (41%), various arterial variations were determined. In 11 of the donors (11%), variations were not compatible with the description of Michel's classification. In all of our patients, CTA findings were confirmed with operational findings. Our complication rate was 1%. Only 1 of the patients who had undergone the transplantation developed hepatic arterial thrombus, and the remaining 99 patients had no arterial complications.

CONCLUSIONS

The course of the vascular structures before live donor liver transplantation is essential for planning and success of the operation. Our study showed that multidetector CTA can be used successfully in hepatic artery imaging of liver transplantation donors as a noninvasive method.

Imaging evaluation of the liver using multi-detector row computed tomography in micropigs as potential living liver donors

The shortage of organ donors has stimulated interest in the possibility of using animal organs for transplantation into humans. In addition, pigs are now considered to be the most likely source animals for human xenotransplantation because of their advantages over non-human primates. However, the appropriate standard values for estimations of the liver of micropigs have not been established. The determination of standard values for the micropig liver using multi-detector row computed tomography (MDCT) would help to select a suitable donor for an individual patient, determine the condition of the liver of the micropigs and help predict patient prognosis. Therefore, we determined the standard values for the livers of micropigs using MDCT. The liver parenchyma showed homogenous enhancement and had no space-occupying lesions. The total and right lobe volumes of the liver were 698.57 ± 47.81 ml and 420.14 ± 26.70 ml, which are 51.74% and 49.35% of the human liver volume, respectively. In micropigs, the percentage of liver volume to body weight was approximately 2.05%. The diameters of the common hepatic artery and proper hepatic artery were 6.24 ± 0.20 mm and 4.68 ± 0.13 mm, respectively. The hepatic vascular system of the micropigs was similar to that of humans, except for the variation in the length of the proper hepatic artery. In addition, the diameter of the portal vein was 11.27 ± 0.38 mm. In conclusion, imaging evaluation using the MDCT was a reliable method for liver evaluation and its vascular anatomy for xenotransplantation using micropigs.

Anatomic variations of the hepatic arteries in 250 patients studied with 64-row CT angiography

The aim of our study was to determine the frequency of different hepatic arterial variants identified on abdominal CT angiography (CTA) with a 64-row CT system and a high resolution protocol. A total of 250 consecutive abdominal CTAs performed on a 64-row CT system were evaluated. Two radiologists in consensus analyzed arterial phase images; the anatomical findings were grouped according to Michels' classification. An anomalous arterial pattern was observed in 34% of the cases. The most common anomaly was Michels type III (9.2%), followed by types II and V (5.2%), type VI (4.0%), types IV, VII, and IX (2.0%), and type VIII (0.6%). No cases of type X were detected. Unclassified variations were observed in 3.3% of the cases. The new generation of 64-row MDCT allows optimal visualization of splanchnic vascular anomalies with a minimally invasive examination. This visualization is extended to those vessels with a small caliber and slow flow resulting in difficult recognition by classic angiographic studies. The knowledge of anomalous arterial patterns could be very useful in the preoperative planning of surgical and interventional liver procedures.

[Left hepatic artery: anatomical variations and clinical implications]

The presence of a left hepatic artery (LHA) is an anatomical variation related to the persistence after fetal maturation of one of the two embryonic hepatic arteries, who disappear in the modal liver arterial vascularisation (liver vascularisation by a unique hepatic artery originating from the celiac trunk). When present, LHA is originating from the left gastric artery and runs through the pars condensa of the lesser omentum. Its frequency is varying from 12 to 34% according to the different study methods: 14 to 27% in anatomical series, 12 to 20% in angiographic studies and 12 to 24% in liver transplantation series. Laparoscopic detection has the highest sensitivity with reported rates from 18 to 34% of cases. LHA is irrigating a variable liver territory from a part of the left lobe to the whole liver in less than 1% of cases. A satisfactory knowledge of these anatomical variations is mandatory in liver surgery and during liver transplantation but also each time the pars condensa is approached during gastric surgery, hiatal surgery for gastroesophageal reflux and for bariatric surgery. Due to existing anastomosis between liver arteries, LHA ligation is feasible in most cases with a subsequent and transitory elevation of liver enzymes. On the contrary, in case of a unique LHA for the whole liver, the safety of its ligation is not demonstrated.

Vascular and biliary variants in the liver: implications for liver surgery

Accurate preoperative assessment of the hepatic vascular and biliary anatomy is essential to ensure safe and successful hepatic surgery. Such surgical procedures range from the more complex, like tumor resection and partial hepatectomy for living donor liver transplantation, to others performed more routinely, like laparoscopic cholecystectomy. Modern noninvasive diagnostic imaging techniques, such as multidetector computed tomography (CT) and magnetic resonance (MR) imaging performed with liver-specific contrast agents with biliary excretion, have replaced conventional angiography and endoscopic cholangiography for evaluation of the hepatic vascular and biliary anatomy. These techniques help determine the best hepatectomy plane and help identify patients in whom additional surgical steps will be required. Preoperative knowledge of hepatic vascular and biliary anatomic variants is mandatory for surgical planning and to help reduce postoperative complications. Multidetector CT and MR imaging, with the added value of image postprocessing, allow accurate identification of areas at risk for venous congestion or devascularization. This information may influence surgical planning with regard to the extent of hepatic resection or the need for vascular reconstruction.

Multidetector-row CT angiographic imaging of the celiac trunk: anatomy and normal variants

PURPOSE

To evaluate the ability of MDCT reformations in describing the celiac trunk vascular anatomy and variations.

MATERIALS AND METHODS

A total of 555 MDCT angiographies of the abdominal aorta performed between January 2002 and July 2005 were retrospectively reviewed to assess the celiac trunk vascular anatomy and variations. All the patients with pathological condition likely to affect normal vascular anatomy as well as CT exams technically inadequate were excluded from our study.

RESULTS

A total of 524 MDCT angiographies of abdominal aorta were included in our study. The classical configuration of the celiac trunk was detected in 72.1%. The hepato-splenic trunk was detected in 50.4% of cases; the hepato-gastro-splenic trunk was detected in 19.4% of cases; the gastro-splenic trunk was detected in 2.3% of cases. The hepato-spleno-gastric trunk associated with hepatic arteries variants were found in 15.4%. The hepato-splenic trunk, the hepato-gastric trunk, the hepato-splenic-mesenteric trunk, and the spleno-gastric trunk were found in 2.7, 5, 0.4, and 3.6%, respectively. In 0.6%, we found an absent celiac trunk.

CONCLUSION

The knowledge of the type of anatomical variants and their subtypes is fundamental for a correct pre-operative vascular planning in surgical or radiological abdominal procedures. Multidetector-row CT (MDCT) provides high-quality 3D-reconstructed images and allows non-invasive assessment of normal anatomy and anatomic variants of celiac trunk.

Ultrasound examination of the liver: Normal vascular anatomy

Various treatments for liver diseases, including liver transplant (particularly partial liver resection from a living donor), treatment of liver tumors, and TIPS, require detailed knowledge of the complex vascular anatomy of the liver. The hepatic artery and portal vein provide the organ with a double blood supply whereas venous drainage is furnished by the hepatic veins.Multislice computed tomography and magnetic resonance imaging provide undeniably excellent information on these structures. On ultrasound, the inferior vena cava, the openings of the hepatic veins, and the main branch of the portal vein can always be visualized, but intrasegmental vessels (portal, arterial, accessory hepatic venous branches) can be only partially depicted and in some cases not at all.In spite of its difficulty and limitations, hepatic sonography is frequently unavoidable, particularly in critically ill patients, and the results are essential for defining diagnostic and therapeutic strategies. For this reason, a thorough knowledge of the sonographic features of hepatic vascular anatomy is indispensable.

Current trends in live liver donation

The introduction of living donor liver transplantation (LDLT) has been one of the most remarkable steps in the field of liver transplantation (LT), able to significantly expand the scarce donor pool in countries in which the growing demands of organs are not met by the shortage of available cadaveric grafts. Although the benefits of this procedure are enormous, the physical and psychological sacrifice of the donors is immense, and the expectations for a good outcome for themselves, as well as for the recipients, are high. We report a current overview of the latest trends in live liver donation in its different aspects (i.e. donor's selection, evaluation, operation, morbidity, mortality, ethics and psychology). This review is based on our center's personal experience with almost 200 LDLTs and a detailed analysis of the international literature of the last 7 years about this topic. Knowing in detail how to approach to the different aspects of living liver donation may be helpful in further improve donor's safety and even recipient's outcome.

Predicting Biliary Complications in Right Lobe Liver Transplant Recipients according to Distance between Donor's Bile Duct and Corresponding Hepatic Artery

PURPOSE

To retrospectively determine whether biliary complications in recipients of living-donor right lobe liver grafts can be predicted at pretransplantation donor computed tomography (CT).

MATERIALS AND METHODS

The human research committee approved this study. The requirement for informed consent was waived. Multi-detector row CT cholangiography and CT angiography were performed in 44 consecutive right lobe liver donors (25 men, 19 women; mean age, 37 years). When CT cholangiography in the donor demonstrated the right biliary anatomy (conventional or variant), the shortest distance between the right main (or second-order) hepatic artery and the corresponding right main (or second-order) bile duct was measured and compared with posttransplantation biliary complications in the transplant recipient by using generalized estimating equations.

RESULTS

In 22 transplant recipients with one right main duct-to-common duct anastomosis (ie, conventional donor anatomy), the distance between the donor's right main bile duct and hepatic artery generally was small (mean distance, 3.8 mm; range, 1-14 mm) and unrelated (P=.46) to biliary complications (n=6). In 22 recipients who required two second-order right duct anastomoses (ie, with variant donor anatomy), the distance between the donor's second-order duct and corresponding hepatic artery was more variable (mean distance, 6.6 mm; range, 1-32.5 mm), and biliary complications were significantly more common when this distance was 10 mm or greater (in eight of 13 ducts with conventional anatomy and four of 31 ducts with variant anatomy, P<.05).

CONCLUSION

Right lobe liver graft recipients who have variant right biliary anatomy and a second-order bile duct 10 mm or farther from the corresponding hepatic artery are at high risk for biliary complications, possibly because of a predisposition to ischemic injury.

Anatomical variations of the hepatic artery: study of 932 cases in liver transplantation

The aim of this study was to identify and to classify anatomical hepatic artery (HA) variations concerning 932 HA dissections in liver transplantation (LT). Normal HA distribution was found in 68.1%. Variations of HA were detected in 31.9% and were divided into three groups describing 48 common hepatic artery (CHA) anomalies, 236 left or right hepatic artery (RHA) anomalies and 13 rare variations including one case of RHA stemmed from the inferior mesenteric artery and one case of normal CHA passed behind the portal vein. The authors propose a modified classification for HA anomalies which are based on the origin of the hepatic arterial supply (either by the CHA as the only source of the arterial vascularization or by additional or replaced right and left arteries) in order to improve management of liver disease thus as in LT.

Preoperative evaluation of the hepatic vascular anatomy in living liver donors: Comparison of CT angiography and MR angiography

PURPOSE

To compare the diagnostic performance of CT angiography (CTA) and MR angiography (MRA) for preoperative hepatic vascular evaluation in living liver donors.

MATERIALS AND METHODS

Twenty-eight living donor candidates underwent preoperative CTA and MRA. Two blinded radiologists evaluated the anatomic types of the hepatic artery (HA) and portal vein (PV), and the number of aberrant hepatic veins (HVs) on both CTA and MRA, independently. Four grades of confidence levels were used to indicate the clarity of depiction of the HA and PV. Surgical findings were used as a standard of reference.

RESULTS

For determining the anatomic types of the HA and PV, and the number of aberrant HVs, CTA and MRA did not significantly differ in terms of accuracy ([89%, 96%, and 68% on CTA] vs. [86%, 93%, and 68% on MRA] for reader 1, P>0.05; and [93%, 100%, and 86% on CTA] vs. [89%, 93%, and 79% on MRA] for reader 2, P>0.05). Confidence for the depiction of major branches of HA and PV did not differ between CTA and MRA, except for a better depiction of the left HA (LHA) on CTA (P<0.05)

CONCLUSION

In living donor candidates, both CTA and MRA can provide a complete evaluation of the hepatic vascular anatomy.

Multidetector CT Angiography of the Abdomen

Multidetector CT angiography (MDCTA) is redefining traditional imaging strategies of the vascular structures of the abdomen. Angiographic depiction of normal and variant anatomy is becoming the standard for evaluation and has a significant impact in transplant and oncologic surgery. MDCTA is increasingly being used for assessing diseases affecting the vasculature of the abdominal organs, including the abdominal aorta for treatment planning and post therapy follow-up.