Intrahepatic biliary anatomy of living adult liver donors: correlation of mangafodipir trisodium-enhanced MR cholangiography and intraoperative cholangiography

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

Background

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

Results

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

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

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

Conclusion

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

Contrast Agents for MR Imaging

Contrast media are essential to the practice of MR imaging. An increasing variety of agents have been approved for clinical use, specific contrast agents can often be tailored to a specific clinical question. Compared with CT contrast media, MR imaging contrast is well tolerated with an excellent safety record and a low incidence of adverse events. In this article, we review the pharmacology, indications, and the common adverse events of the intravenous and oral MR contrast agents most commonly used in contemporary imaging practice, including gadolinium-based contrast, manganese and iron-based agents and the most common oral contrast agents.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Ligation and cut as a method for bile duct division in living donor right hepatectomy

The importance of bile duct division cannot be overemphasized in living donor surgery. Ligation and cut (LC) as a method for bile duct division in living donor right hepatectomy (LDRH) has never been reported. The purpose of this study was to introduce the LC method of bile duct division in LDRH. All LDRH donors were identified through a prospectively maintained database at the authors' institution between September 2009 and March 2013, and the 2 methods, LC and cut and oversewing (CO), were compared both in terms of donor and recipient outcomes of right lobe living donor liver transplantation. In the LC method, after complete parenchymal transection, the right hepatic duct was dissected in the Glisson's sheath and ligated just at the right side of the confluence, and then the right side of the ligature was cut. The LC and CO methods were performed in 109 and 134 donors, respectively. Bile duct division time (P < 0.001) and operative time (P < 0.001) were significantly shorter in the LC group than in the CO group. With a median follow-up of 60.2 months, biliary complication rate was lower in the LC group than in the CO group (0% versus 5.2%; P = 0.01), but with no significant difference between the recipient groups. All donors made a complete recovery. In conclusion, the bile ducts of living donors can be dissected safely from the Glisson's sheath, and the LC method facilitates bile duct division and has a lower incidence of biliary complication in LDRH without compromising the recipient outcomes. Liver Transplantation 23 448-456 2017 AASLD.

Robotic liver donor right hepatectomy: A pure, minimally invasive approach

Right hepatectomy for a living liver donor via a pure minimally invasive approach is a challenging procedure and only a few cases have been reported. Between May 2013 and August 2015, 13 patients underwent robotic living donor right hepatectomy in our institute, and 54 patients received open surgery. In this series, no conversion was conducted for robotic donor right hepatectomy. The 2 groups shared similar blood loss (169 versus 146 mL), complication rates (7.7% versus 9.3%), and recovery of donor liver function (peak alanine aminotransferase, 269 versus 252 IU/mL). The robotic group needed longer operation time (596 versus 383 minutes) but less postoperative patient-controlled analgesia (0.58 versus 0.84 ng/kg) and a shorter period before returning to work/school (52.9 versus 100.0 days) and sex (100.0 versus 156.0 days). For recipient outcomes regarding the donor procedure, the robotic group shared similar experiences in early allograft dysfunction, complications, and 1-year recipient liver function with the open group. With respect to documented benefits of minimally invasive left-sided liver donor procedure, the development of right donor hepatectomy is slow. In conclusion, with substantial improvements in patient recovery after the minimally invasive approach, the robotic platform would be a big step toward completing pure minimally invasive liver donor surgery. Liver Transplantation 22 1509-1518 2016 AASLD.

Contrast-enhanced MR cholangiography with Gd-EOB-DTPA for preoperative biliary mapping: correlation with intraoperative cholangiography

BACKGROUND

Gd-EOB-DTPA-enhanced magnetic resonance (MR) could be used for preoperative evaluation of bile duct anatomy in addition to conventional information of focal hepatic lesions.

PURPOSE

To evaluate accuracy of contrast-enhanced MR cholangiography (CE MRC) reconstructed from Gd-EOB-DTPA-enhanced MR images for depicting biliary anatomy with intraoperative cholangiography.

MATERIAL AND METHODS

We retrospectively identified 71 patients who underwent both preoperative Gd-EOB-DTPA-enhanced MR imaging (MRI) and intraoperative cholangiography for hepatic resections. Two readers independently analyzed biliary anatomy using CE MRC reconstructed from transverse and coronal images separately in 4 weeks. The accuracy and diagnostic confidence were evaluated in correlation with intraoperative cholangiography. The accuracy and confidence score (3-point scale) were compared on CE MRCs from transverse versus coronal images.

RESULTS

CE MRCs correctly depicted biliary anatomy in 91.5% and 88.7% with coronal images and in 81.7% and 73.2% with transverse images for readers 1 and 2, respectively. CE MRCs from coronal images tended to show greater accuracy (P = 0.12 and 0.01, for readers 1 and 2) and higher confidence score (P = 0.11 and P = 0.04, for readers 1 and 2) than those from transverse images.

CONCLUSION

Accurate preoperative biliary mapping can be achieved on CE MRC reconstructed from Gd-EOB-DTPA-enhanced MR images. The diagnostic performance was better on CE MRC reconstructed from coronal than those from transverse images.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Pushing the frontiers of living donor right hepatectomy

Living donor right hepatectomy (LDRH) is currently the most common donor surgery in adult-to-adult living donor liver transplantation although the morbidity and mortality reported in living donors still contradicts the Hippocratic tenet of “do no harm”. Achieving low complication rates in LDRH remains a matter of major concern. Living donor surgery is performed worldwide as an established solution to the donor shortage. The aim of this study was to assess the current status of LDRH and comment on the future of the procedure; assessment was made from the standpoint of optimizing the donor selection criteria and reducing morbidity based on both the authors’ 8-year institutional experience and a literature review. New possibilities have been explored regarding selection criteria. The safety of living donors with unfavorable conditions, such as low remnant liver volume, fatty change, or old age, should also be considered. Abdominal incisions have become shorter, even without laparoscopic assistance; upper midline laparotomy is the primary incision used in more than 400 consecutive LDRHs in the authors’ institution. Various surgical techniques based on preoperative imaging technology of vascular and biliary anomalies have decreased the anatomical barriers in LDRH. Operative time has been reduced, with low blood loss. Laparoscopic or robotic LDRH has been tried in only a few selected donors. The LDRH-specific, long-term outcomes remain to be addressed. The follow-up duration of these studies should be long enough to address possible late complications. Donor safety, which is the highest priority, is ensured by three factors: preoperative selection, intraoperative surgical technique, and postoperative management. These three focus areas should be continuously refined, with the ultimate goal of zero morbidity.

Presurgical planning for hepatobiliary malignancies: clinical and imaging considerations

There are many considerations in the evaluation of liver malignancy before planned surgical treatment. This article focuses on interpretation of MR imaging of the liver for surgical treatment planning of hepatocellular carcinoma, colorectal cancer metastases, and hilar cholangiocarcinoma. Clinical status, anatomic variants, future liver remnant, and underlying liver disease are all important factors in the decision to proceed with liver resection. The primary objective of preoperative imaging is to correctly identify patients who are candidates for curative intervention and to accurately stage their disease. Treatment planning for these complex patients is best done with a multidisciplinary team approach.

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.

Improving outcomes of living-donor right hepatectomy

BACKGROUND

Complication rates of living-donor right hepatectomy remain a matter of major concern. The aim of this study was to achieve near-zero morbidity for living-donor right hepatectomy in a single centre.

METHODS

All living donors who underwent right hepatectomy between January 2005 and September 2011 were enrolled in this retrospective study. During this interval, modifications in surgical technique and management included upper midline laparotomy, use of wound protectors, hanging manoeuvre during parenchymal transection using Glisson's approach, no intraoperative cholangiography, no intensive care unit stay after surgery, no central venous catheterization, and reduction in systemic heparin dose before graft removal. Donor characteristics, operative outcomes and complications graded according to Clavien's classification were recorded.

RESULTS

A total of 300 donors were enrolled and these were divided into three groups of 100 operated on in consecutive time periods. Groups were comparable with regard to donor characteristics. The overall complication rate was 16·0 per cent, with no deaths. From group 1 to group 3, the duration of operation (P < 0·001), length of hospital stay (P < 0·001), and rate of overall (P < 0·001) and grade IIIb (P = 0·019) complications decreased significantly. In the most recent group, the morbidity rate was 3·0 per cent without any major complications, reoperation or blood transfusions. All donors recovered completely.

CONCLUSION

This study suggests that near-zero morbidity may be reached after right hepatectomy in carefully selected living donors by continuous refinement of surgical technique and management.

Intrahepatic transposition of bile ducts

Objective. To describe the intrahepatic bile duct transposition (anatomical variation occurring in intrahepatic ducts) and to determine the frequency of this variation. Material and Methods. The researches were performed randomly on 100 livers of adults, both sexes. Main research methods were anatomical macrodissection. As a criterion for determination of variations in some parts of bile tree, we used the classification of Segmentatio hepatis according to Couinaud (1957) according to Terminologia Anatomica, Thieme Stuugart: Federative Committee on Anatomical Terminology, 1988. Results. Intrahepatic transposition of bile ducts was found in two cases (2%), out of total examined cases (100): right-left transposition (right segmental bile duct, originating from the segment VIII, joins the left liver duct-ductus hepaticus sinister) and left-right intrahepatic transposition (left segmental bile duct originating from the segment IV ends in right liver duct-ductus hepaticus dexter). Conclusion. Safety and success in liver transplantation to great extent depends on knowledge of anatomy and some common embryological anomalies in bile tree. Variations in bile tree were found in 24–43% of cases, out of which 1–22% are the variations of intrahepatic bile ducts. Therefore, good knowledge on ductal anatomy enables good planning, safe performance of therapeutic and operative procedures, and decreases the risk of intraoperative and postoperative complications.

Relationship between the risk of bile duct injury during laparoscopic cholecystectomy and the types of preoperative magnetic resonance cholangiopancreatiocography (MRCP)

Backgrounds/Aims

Bile duct injury is one of the potential severe complications that can occur during laparoscopic cholecystectomy, which can be cause by anatomic variations in the confluence of the bile duct. Recently magnetic resonance cholangiopancreatiocography (MRCP) has become a helpful tool to detect bile duct variation on a preoperative basis and to prevent bile duct injury during laparoscopic cholecystectomy, as well other hepatic surgeries. This study aimed to clarify the types of bile duct on MRCP and to search for a method of avoiding injury during laparoscopic cholecystectomy.

Methods

Between January 2009 and December 2010, 277 patients underwent laparoscopic cholecystectomy with preoperative MRCP in our institution. On a retrospective basis, the bile ducts were categorized into 5 types according to the Couinaud classification system.

Results

The proportion of types was revealed type A (70.4%), type B (8.7%), type C (19.5%), type D (0.7%), type E (0%), and type F (0.7%), respectively. Bile duct injury occurred in 4 cases (1.4%) during laparoscopic cholecystectomy. In particular, the possibility of aberrant extrahepatic confluence (Type C and F) represented the highest risk of duct injury (OR=11.89 [CI: 1.21-116.53]).

Conclusions

Preoperative evaluation of the bile duct anatomy is important to avoid injury of duct during laparoscopic cholecystectomy. Specific types of bile duct variation should be considered as a high risk group for bile duct injury.

Technical aspects of biliary reconstruction in adult living donor liver transplantation

BACKGROUND

The last decade has witnessed great progress in living donor liver transplantation worldwide. However, biliary complications are more common in partial liver transplantation than in whole liver transplantation. This is due to an impaired blood supply of the hilar bile duct during organ procurement and recipient surgery, commonly encountered anatomical variations, a relatively small graft duct, and complicated surgical techniques used in biliary reconstruction.

DATA SOURCES

MEDLINE and PubMed were searched for articles on "living donor liver transplantation", "biliary complication", "anatomical variation", "biliary reconstruction", "stenting" and related topics.

RESULT

In this review, biliary complications were analyzed with respect to anatomical variation, surgical techniques in biliary reconstruction, and protection of the arterial plexus of the hilar bile duct.

CONCLUSION

Transecting the donor bile duct at the right place to secure a larger bile duct stump, anastomosing techniques, and stenting methods as well as preserving the blood supply to the bile duct are all important in reducing biliary complications.

Right anterior segmental hepatic duct emptying directly into the cystic duct in a living donor

A 35-year-old mother was scheduled to be the living donor for liver transplantation to her second son, who suffered from biliary atresia complicated with biliary cirrhosis at the age of 2 years. The operative plan was to recover the left lateral segment of the mother’s liver for living donor transplantation. With the use of cholangiography at the time of surgery, we found the right anterior segmental duct (RASD) emptying directly into the cystic duct, and the catheter passed into the RASD. After repairing the incision in the cystic duct, transplantation was successfully performed. Her postoperative course was uneventful. Biliary anatomical variations were frequently encountered, however, this variation has very rarely been reported. If the RASD was divided, the repair would be very difficult because the duct will not dilate sufficiently in an otherwise healthy donor. Meticulous preoperative evaluation of the living donor’s biliary anatomy, especially using magnetic resonance cholangiography and careful intraoperative techniques, is important to prevent bile duct injury and avoid the risk to the healthy donor.

Initial experience on utility of gadobenate dimeglumine (Gd-BOPTA) enhanced T1-weighted MR cholangiography in diagnosis of acute cholecystitis

PURPOSE

To investigate the feasibility of the use of gadobenate dimeglumine (also known as Gd-BOPTA) -enhanced T1-weighted MR cholangiography in diagnosis of acute cholecystitis.

MATERIALS AND METHODS

This prospectively designed institutional review board-approved HIPAA-compliant study was done between January and November 2007. We included 11 consecutive patients (7 male, mean age 59 years) who presented to the emergency room with acute right upper quadrant pain and with equivocal physical examination and/or ultrasound findings. The control group included 15 patients who underwent liver MRI with Gd-BOPTA. All patients underwent contrast-enhanced (CE) MR cholangiography examinations. CE-MR cholangiography was performed on a 1.5 Tesla magnet using 3D T1-weighted high resolution isotrophic volume examination (THRIVE) obtained at the 90th min after intravenous injection of Gd-BOPTA. Imaging features detected on CE-MR cholangiography were correlated with operative and histopathologic findings.

RESULTS

In the control group, GD-BOPTA was visualized within the gallbladder in all subjects. For the study group, gallstones were present in nine patients (n = 7 both in gallbladder and cystic duct, n = 1 only in gallbladder, n = 1 only in cystic duct) on MRCP. Hydropic gallbladder was detected in seven patients, significant wall thickening in seven patients, and pericholecystic free fluid in 6 patients. On delayed phase CE cholangiography, significant enhancement of gallbladder wall was seen in 10 patients, and contrast agent excretion into gallbladder was absent in all patients. Surgery was performed in 10 patients, and cholecystostomy was done in 1 patient. Surgery and histopathology findings were consistent with cholecystitis in all patients.

CONCLUSION

In addition to anatomical assessment, Gd-BOPTA-enhanced MR cholangiography can provide functional evaluation similar to HIDA scintigraphy in diagnosing acute cholecystitis in patients with acute right upper quadrant pain and equivocal findings.

Morphine- and glucagon-augmented magnetic resonance cholangiopancreatography to evaluate living liver donors

The purpose of this study was to investigate the effectiveness of the combined use of intravenous morphine and intramuscular glucagon in improving magnetic resonance cholangiopancreatography (MRCP) image quality in donors for living-related liver transplantation. Sixteen healthy donor candidates underwent an MRCP study. Coronal, single-shot, fast spin-echo, heavily T2-weighted dynamic MRCP images were obtained before and 3 minutes after the intravenous administration of morphine HCl with a dose of 0.04 mg/kg. Thirty minutes after the injection of morphine, intramuscular glucagon was used. Another MRCP image of the same pulse sequence was generated 15 minutes after the injection of glucagon with a dose of 1 mg. The diameter, signal intensity, and number of branches of bile ducts in MRCP images taken immediately before and after the injection of morphine and after the injection of glucagon (plus delayed morphine effects) were compared and analyzed. In all 16 donor candidates, the diameters of the right and left hepatic ducts, common bile duct, and main pancreatic duct were significantly increased (P < 0.05) in the MRCP images taken 3 minutes after the injection of morphine and 15 minutes after the injection of glucagon (plus delayed morphine effects) in comparison with MRCP images taken before any drug administration. The qualitative grading scores of the signal intensity and order of branches of bile ducts revealed improvements in the MRCP images after the injection of glucagon (plus delayed morphine effects; P < 0.05). In conclusion, combining the intravenous administration of low-dose morphine and the intramuscular use of glucagon before MRCP examination improves the visualization of the nondilated biliary ductal anatomy, which is important for the preoperative biliary evaluation of donor candidates for living-related liver transplantation.

O papel da colangiografia por ressonância magnética na avaliação da anatomia biliar em doadores de transplante hepático intervivos

OBJETIVO: Avaliar a acurácia da colangiografia por ressonância magnética no estudo da anatomia biliar de doadores de fígado em correlação com achados operatórios. MATERIAIS E MÉTODOS: Estudo retrospectivo de 50 doadores submetidos a transplante hepático intervivos no Hospital de Clínicas da Universidade Federal do Paraná, Curitiba, PR. As colangiografias foram analisadas e os resultados dos exames foram comparados com os achados intra-operatórios. Apenas alterações anatômicas que promoveram mudança de estratégia cirúrgica, não-evidenciadas previamente pela colangiografia por ressonância magnética, foram consideradas como discordantes. RESULTADOS: Foram encontradas variações pela colangiografia por ressonância magnética em 7 doadores e em 14 durante a cirurgia. Do total de pacientes, 41 resultados foram concordantes e 9 foram discordantes. A sensibilidade, a especificidade, o valor preditivo positivo, o valor preditivo negativo e a acurácia da colangiografia por ressonância magnética foram, respectivamente, de 43%, 97%, 86%, 81% e 81,6%. CONCLUSÃO: Conclui-se que a ressonância magnética é um método de imagem seguro e não-invasivo para avaliação pré-operatória das vias biliares de doadores e que algumas anomalias não são detectadas pela colangiografia por ressonância magnética.

MR cholangiopancreatography with T2-weighted prospective acquisition correction turbo spin-echo sequence of the biliary anatomy of potential living liver transplant donors

OBJECTIVE

The objective of our study was to evaluate the ability of a respiratory navigator-triggered T2-weighted turbo spin-echo (TSE) sequence with a prospective acquisition correction (PACE) technique for MR cholangiopancreatography (MRCP) to depict the biliary anatomy of living donor liver transplantation (LDLT) donors.

SUBJECTS AND METHODS

Forty potential LDLT donors who ranged in age from 19 to 54 years were prospectively evaluated with preoperative MRCP. MRCP was performed with a 1.5-T magnetic field using T2-weighted PACE TSE sequence. MRCP source data sets were processed with maximum-intensity-projection (MIP) and shaded surface display (SSD) algorithms. Findings were compared with intraoperative cholangiography. Biliary anatomy was classified according to the classification proposed by Huang and colleagues. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of MRCP for the detection of aberrant biliary anatomy were calculated.

RESULTS

Intraoperative cholangiography and biliary exploration revealed that 27 donor candidates (67.5%) had conventional and 13 (32.5%) had aberrant biliary anatomy. Two donors (5%) had type B biliary anatomy; eight donors (20%), type C; two donors (5%), type D; and one donor (2.5%), unclassified. The sensitivity of MRCP source data sets in differentiating aberrant biliary anatomies from nonaberrant ones was 100%, the specificity was 88.9%, and the accuracy was 92.5%. PPV and NPV were 81.3% and 100%, respectively. The sensitivity of MIP images in differentiating aberrant biliary anatomies was 100%, the specificity was 88.9%, and the accuracy was 92.5%. PPV and NPV were 81.3% and 100%, respectively. The sensitivity, specificity, accuracy, PPV, and NPV of the SSD images in detecting aberrant biliary anatomies were 100%, 77.8%, 85%, 68.4%, and 100%, respectively.

CONCLUSION

Preoperative MRCP using a respiratory navigator-triggered T2-weighted TSE sequence with a PACE technique accurately depicts the biliary anatomy in LDLT donors and may guide intraoperative management of the biliary tract.

Bile duct anatomy of the Anatolian Caucasian population: Huang classification revisited

BACKGROUND AND OBJECTIVES

Living donor liver transplantations (LDLT) donor candidates are being assessed with MRCP (magnetic resonance cholangiopancreatography) to identify their suitability for standard surgical techniques. Variations of the bile duct anatomy play an important role in donor selection and in the selection of the resection technique. If bile duct anatomy is misrecognized, complications may occur. Anatomic variations are classified according to the origin of the right posterior hepatic duct (RPHD). According to the so called Huang classification, type A1 is the most, and type A5 is the least frequent variation. These frequencies were initially validated on Chinese population. Later studies revealed significant variability in frequency for the so called trifurcation, the variation in which a common junction of RHPD, right anterior hepatic duct (RAHD) and left hepatic duct (LHD) (A2) exists. In this study we aimed to determine the bile duct anatomy variations for the Anatolian Caucasians.

METHODS

One hundred and thirty-four healthy subjects were investigated under 1.5 T MRI, with breath-hold (expiration) heavily T2-weighted turbo spin echo (TSE) static fluid imaging (TR/TE=8,000/800). The sequence has permitted three to five oblique coronal thick sections (40 mm) around a common axis. Sequences were repeated until anatomically interpretable images were obtained. Diagnostic images could not be obtained in 22 subjects. Radiologists who were fully experienced in LDLT assessment investigated these images, and classified them for the surgical variations of the bile duct anatomy.

RESULTS

One hundred and twelve subjects (58 men, 54 women) who were classified were between 14 and 81 years of age (mean: 39.3; SD 14.1). According to Huang classification, 61 of them (55%) were classified as type A1 (normal right and left hepatic duct junction), 16 (14%) as type A2 (common junction of RAHD, RHPD and LHD), 24 (21%) as type A3 (aberrant drainage of RPHD to left main duct), and 11 (10%) as type A4 (aberrant drainage of RPHD to main hepatic duct). When subjects, in whom the distance (d) between RPHD insertion and the right and left hepatic duct junction is less than 1 cm, are classified as type A2, the type A1 prevalence decreases to 28%. For the entire population that distance was between 3 and 25 mm (mean: 9.8, SD: 4.8). Accordingly, the frequency of type A1 anatomy was 8-29% lower than the respective frequency in Chinese population.

CONCLUSION

From the surgical perspective, close proximity (d<1 cm) of RPHD to right and left hepatic duct junction is considered as type A2 variation. According to that concept, type A1, usually accepted as the dominant anatomic variation, is encountered only in 28% of the Anatolian Caucasians. We have proposed a modified surgical classification in which Huang type 2 was subdivided into types K2a (close proximity) and K2b (trifurcating). The predominance of K2 types in the population of the study may necessitate the use of bench ductoplasty in many liver grafts.

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.

Visualization of the biliary tract using gadobenate dimeglumine: preliminary findings

OBJECTIVE

To compare contrast-enhanced magnetic resonance (MR) cholangiography (CE-MRC) performed with gadobenate dimeglumine with T2-weighted MRC (T2-MRC) for visualization of the bile ducts in nondilated biliary systems.

MATERIALS AND METHODS

Twenty consecutive patients who underwent MR imaging (MRI) of the liver and pancreas with nondilated intrahepatic ducts were included in this retrospective study. T2-weighted MRC was performed using a multislice, high-resolution fat-suppressed half-Fourier acquisition turbo spin-echo sequence. Contrast-enhanced MR cholangiography was performed using a fat-suppressed 3-dimensional fast low-angle shot sequence acquired 1 to 1.5 hour after intravenous administration of gadobenate dimeglumine. For image interpretation, the biliary system was divided into 8 segments. Two readers graded visualization of each segment on T2-MRC and CE-MRC using a 5-point scale (0, nonvisualization; 4, excellent visualization). Final opinion for each sequence was rendered by consensus. Superiority of visualization was assessed using the McNemar test and comparing adequately (visualization scores 3 and 4) and inadequately (visualization scores 0, 1, and 2) visualized segments of the ducts on both sequences. Interobserver variability was assessed with kappa statistics.

RESULTS

Overall and segment-based evaluation revealed superior visualization of biliary segments with CE-MRC compared with T2-MRC. We also found a statistically significant difference between the 2 sequences for overall and for right hepatic duct and cystic channel visualization (P < 0.05). A high concordance between readers 1 and 2 both for T2-MRC and CE-MRC was achieved (85.8% and 89.4%, respectively).

CONCLUSIONS

Gadobenate dimeglumine can be used as an alternative intrabiliary contrast agent for contrast-enhanced MR cholangiography in nondilated biliary systems in patients with normal excretory liver function tests.

The value of magnetic resonance cholangiography in the preoperative assessment of living liver donors

OBJECTIVE

The purpose of this study was to investigate the ability of magnetic resonance cholangiography (MRC) in the depiction of biliary anatomy of living liver donors by using intraoperative cholangiography (IOC) as a gold standard.

MATERIALS AND METHODS

Between 2004 and 2006, 86 potential adult-to-adult living donor liver transplantation donors had preoperative MRC at our institution. Of these, 24 potential donors were excluded due to various clinical factors. A total of 62 of these individuals were selected for liver donation and included in the study. MRC was performed on a 1.5-T scanner with breath-hold, rapid acquisition with relaxation enhancement (RARE) sequence with half-Fourier acquisition (HASTE; Siemens) and free-breathing, three-dimensional turbo spin-echo sequence with respiratory triggering. Thin- and thick-slab imaging techniques were employed with half-Fourier RARE MRC. IOC was performed in all 63 cases. The images of IOC and MRC were classified according to a modified Huang classification, independently. The results of the MRC were then compared with the IOC results.

RESULTS

IOC was used as the reference standard; a total of 43 (69.3%) liver donors were considered to have normal biliary anatomy, whereas 19 (30.7%) were considered to have variants of biliary anatomy. Compared with IOC, MRC correctly revealed biliary anatomy in 59 of 62 (95.1%) donors. The sensitivity, specificity, positive predictive value and negative predictive value of MRC in distinguishing normal and any type of variant biliary anatomy were 84.2%, 100%, 100%, and 93.4%, respectively.

CONCLUSION

MRC is an effective imaging technique for the preoperative evaluation of the biliary anatomy in living liver donors. However, MRC and IOC should be considered complementary to one another in order to avoid complications.

Evaluation of biliary abnormalities with 64-channel multidetector CT

Precise preoperative assessment of the vascular and biliary anatomy is important in ensuring the safety of hepatobiliary surgical procedures, including laparoscopic cholecystectomy, living donor liver transplantation, and tumor resection of the liver. Endoscopic retrograde cholangiography and percutaneous transhepatic cholangiography clearly depict the biliary anatomy but are considered invasive procedures. Magnetic resonance cholangiopancreatography is noninvasive but sometimes fails to depict the normal intrahepatic bile ducts. Multidetector computed tomography (CT) has contributed greatly to the evaluation of the normal anatomy, anatomic variants, and disease extent in this setting. With 64-channel multidetector CT, high-resolution three-dimensional images can be reconstructed from isotropic data with a 0.625-mm section thickness. Because of its capacity for thin-section scanning and multiplanar reformation, 64-channel multidetector CT cholangiography can clearly demonstrate the biliary anatomy, a variety of anatomic variants, and the extent of disease--information that is indispensable for successful hepatobiliary surgery.

MR cholangiopancreatography: 1.5T versus 3T

Soon after its introduction in 1991, MR cholangiopancreatography has become an established diagnostic tool for the evaluation of the pancreaticobiliary ductal system at a field strength of 1.5T. It remains unclear whether MR cholangiopancreatography performed at 3T will benefit from the higher magnetic field strength or whether a field strength of 1.5T should continue to be considered the gold standard for MR cholangiopancreatography. This article reviews the current literature on the benefits and drawbacks of MR cholangiopancreatography at 3T compared with a standard field strength of 1.5T. Field strength-related artifacts that affect MR cholangiopancreatography at 3T also are discussed.

3D anatomical variations of hepatic vasculature and bile duct for right lateral sector of liver with special reference to transplantation

To achieve a safer living related liver transplantation (LRLT) using the right lateral sector, anatomical variations of the portal vein, hepatic artery and bile duct for the right lateral sector and their three dimentional (3D) relationship were assessed by integrated 3D-CT images. 52 patients who underwent contrast enhanced multi-detector row CT (MD-CT) and MD-CT cholangiography were enrolled. Data from contrast enhanced MD-CT were used to reconstruct the 3D images of the hepatic artery and portal vein. 3D images reconstructed from MD-CT data of the hepatic artery, portal vein and bile duct were integrated into a single image. The dual branching of the right lateral portal vein was observed in 22 (42.3%) patients. Three (5.8%) had dual right lateral ducts and 14 (26.9%) had dual right lateral arteries. Among them, "south-turning" artery and "north-turning" bile duct was observed in 22 (42.3%). "South-turning" artery and "south-turning" bile duct were 3 (5.8%). "North-turning" artery and "north-turning" bile duct were 2 (7.4%). Only 27 (51.9%) had single portal vein, bile duct and artery for the right lateral sector, those were preferable as candidates for right lateral sector graft transplantation. 3D anatomical variations of portal vein, artery and bile duct for the right lateral sector were complexed, and only half of the donor candidates had preferable hepatic structures for right lateral sector graft transplantation. Understanding of the 3D hepatic structures by 3D-CT may contribute to a better definition of anatomical contraindications for LRLT which may further results in more safe and widely applied right lateral sector graft LRLT.

Infraportal bile duct of the caudate lobe: a troublesome anatomic variation in right-sided hepatectomy for perihilar cholangiocarcinoma

OBJECTIVE

We present our experiences with infraportal bile duct of the caudate lobe (B1) and discuss surgical implications of this rare variation.

SUMMARY BACKGROUND DATA

Although various authors have investigated biliary anatomy at the hepatic hilum, an infraportal B1 (joining the hepatic duct caudally to the transverse portion of the left portal vein) has not been reported.

METHODS

Between January 1981 and December 2005, 334 patients underwent hepatectomy combined with caudate lobectomy for perihilar cholangiocarcinoma. Four of them (1.2%) had infraportal B1 and were investigated clinicoanatomically.

RESULTS

All infraportal B1 were B1l, draining Spiegel's lobe; no infraportal B1r (draining the paracaval portion) or B1c ducts (draining the caudate process) were found. The infraportal B1l joined the common hepatic duct or the left hepatic duct. Three patients underwent right trisectionectomy with caudate lobectomy; for one, in whom preoperative diagnosis was possible, combined portal vein resection and reconstruction were performed before caudate lobectomy to resect the caudate lobe en bloc without division of infraportal B1. For the other 2 patients, the infraportal B1 was divided to preserve the portal vein, and then the caudate lobe was resected en bloc. The fourth patient underwent right hepatectomy with right caudate lobectomy; the cut end of the infraportal B1 showed no cancer by frozen section, so the bile duct was ligated and divided to preserve the left caudate lobe.

CONCLUSION

Infraportal B1 can cause difficulties in performing right-sided hepatectomy with caudate lobectomy or harvesting the left side of the liver with the left caudate lobe for transplantation. Hepatobiliary and transplant surgeons should carefully evaluate biliary anatomy at the hepatic hilum, keeping this variation in mind.

[New possibilities to study biliary tree and gallbladder: functional magnetic resonance cholangiography contrast-enhanced with mangafodipir trisodium (Mn DPDP)]

Mangafodipir trisodium (Teslascan) is a hepatobiliary contrast agent that provides noninvasive opacification of the bile ducts. Using this contrast medium combined with a T1-weighted gradient echo enhanced sequence provides functional imaging of the bile ducts. Second-intention MRI was obtained after the usual morphological study of the bile ducts using heavily T2-weighted sequences (SS-FSE Te eff long and SS FSE Te eff short). This method can detect many biliary duct anomalies: biliary leakage in the postoperative context, mapping of bile ducts and the gallbladder in the search for anatomical variants, analysis of biliodigestive or biliobiliary anastomoses, or a dynamic study of bile secretion and excretion. Opacification of the bile ducts has only been possible until now with invasive tests aggravated by a certain co-morbidity rate and their functional study using biliary scintigraphy limited by mediocre spatial resolution. This new possibility provides access not only to morphological imaging, but also to functional imaging with excellent spatial resolution.

Preoperative evaluation of biliary anatomy of donor in living donor liver transplantation by conventional nonenhanced magnetic resonance cholangiography

Detailed preoperative evaluation of the biliary anatomy of the donor in living donor liver transplantation (LDLT) can minimize postoperative morbidity in the recipient and maximize safety for the donor. We prospectively evaluated the diagnostic accuracy and clinical usefulness of nonenhanced conventional magnetic resonance cholangiography (MRC) for depicting the biliary anatomy of LDLT donors. MRC and intraoperative cholangiography (IOC) examinations of 111 donors were performed between August 2005 and February 2006. We observed the classical branching pattern of the biliary system in 67 subjects (60.4%), with the remaining 44 subjects (39.6%) showing anatomical variations. MRC showed accurate anatomy of the biliary system, using IOC as the reference standard, in 98 (88.3%) subjects. MRC had a sensitivity in differentiating normal from variant anatomy of 95.5%, specificity of 95.2%, a positive predictive value of 96.8% and a negative predictive value of 93.3%. The agreement between MRC and IOC findings, as evaluated by kappa-value (0.865) was statistically significant (P<0.001). In conclusion, the diagnostic accuracy of conventional nonenhanced MRC is sufficient for this method to be used for the preoperative evaluation of biliary anatomy in LDLT donor candidates.

Gadobenate dimeglumine-enhanced liver MRI as the sole preoperative imaging technique: a prospective study of living liver donors

OBJECTIVE

The objective of our study was to determine whether gadobenate dimeglumine-enhanced MRI is practical as the sole preoperative imaging technique for the examination of living liver donors.

SUBJECTS AND METHODS

Forty-four consecutive living donor candidates underwent liver MRI on a 1.5-T MR unit. The MR examination included in- and opposed-phase T1-weighted gradient-echo imaging, T2-weighted MR cholangiography, MR angiography (MRA) and parenchymal phase imaging after the administration of gadobenate dimeglumine, and 60-minute delayed T1-weighted MR cholangiography. Two abdominal radiologists analyzed the images regarding the depiction of the biliary duct anatomy and the hepatic vascular anatomy and for the presence of focal or diffuse liver disease. The findings were compared with intraoperative cholangiographic and surgical findings in 24 patients who underwent partial hepatectomy.

RESULTS

In the 24 patients who underwent liver harvesting, 10 had biliary anatomic variants confirmed by intraoperative cholangiography. T2-weighted MR cholangiography allowed a correct diagnosis in 75% (n = 18/24) and T1-weighted MR cholangiography in 79% (n = 19/24) of these patients. When we evaluated the bile duct anatomy using the combined findings of T2- and T1-weighted MR cholangiographic images, the diagnostic accuracy increased to 92% (n = 22/24), but the difference was not statistically significant (p > 0.05). MRA showed a diagnostic accuracy of 79% (n = 19/24) for the hepatic arterial anatomy, 100% (n = 24/24) for the portal venous anatomy, and 96% (n = 23/24) for the hepatic venous anatomy.

CONCLUSION

Gadobenate dimeglumine-enhanced MRI allows comprehensive assessment of the biliary and hepatic vascular systems and the hepatic parenchyma and can serve as the sole preoperative imaging test for living liver donor candidates.

Gadobenate dimeglumine as an intrabiliary contrast agent: comparison with mangafodipir trisodium with respect to non-dilated biliary tree depiction

OBJECTIVE

To compare the efficacy of Mangafodipir trisodium (Mn-DPDP)-enhanced MR cholangiogrphy (MRC) and Gadobenate dimeglumine (Gd-BOPTA)-enhanced MRC in visualizing a non-dilated biliary system.

MATERIALS AND METHODS

Eighty-eight healthy liver donor candidates underwent contrast-enhanced T1-weighted MRC. Mn-DPDP and Gd-BOPTA was used in 36 and 52 patients, respectively. Two radiologists reviewed the MR images and rated the visualization of the common duct, the right and left hepatic ducts, and the second-order branches using a 4-point scale. The contrast-to-noise ratio (CNR) of the common duct to the liver in the two groups was also compared.

RESULTS

Mn-DPDP MRC and Gd-BOPTA MRC both showed similar visualization grades in the common duct (p=.380, Mann-Whitney U test). In the case of the proximal bile ducts, the median visualization grade was significantly higher with Gd-BOPTA MRC than with Mn-DPDP MRC (right hepatic duct: p=0.016, left hepatic duct: p=0.014, right secondary order branches: p=0.006, left secondary order branches, p=0.003). The common duct-to-liver CNR of the Gd-BOPTA MRC group was significantly higher (38.90+/-24.50) than that of the Mn-DPDP MRC group (24.14+/-17.98) (p=.003, Student's t test).

CONCLUSION

Gd-BOPTA, as a biliary contrast agent, is a potential substitute for Mn-DPDP.

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

PURPOSE

To retrospectively determine whether major portal venous variation was more frequently associated with biliary variants, with consideration of the types and frequencies of biliary tract variations in the right and left liver lobes.

MATERIALS AND METHODS

Before undergoing computed tomographic (CT) cholangiography, patients gave informed consent. The retrospective research protocol was approved, and informed consent was waived by the ethics committee. Forty-four patients aged 29-80 years who underwent multi-detector row CT cholangiography had a major portal vein variation in which the main portal vein diverged into the common trunk of the left portal vein and right anterior sectorial portal vein. One hundred fifty-eight consecutive patients aged 26-89 years who did not have this variation served as the control group. Three radiologists retrospectively evaluated the confluence pattern of the bile duct, the relationship between this pattern and the portal vein, and the major branching pattern of the portal vein. Pearson chi2 and Fisher exact tests were performed to identify significant differences between the two patient groups.

RESULTS

The classic hilar confluence pattern, where the right posterior sectorial duct connects supraportally with the right anterior sectorial duct, was less frequent in the patients with the portal vein variation than in the control subjects (32% vs 73%, P < .05). The following biliary tract variations were identified more frequently in the variation group than in the control group (P < .05): right posterior sectorial duct joining left hepatic duct with a supraportal course (34% vs 12%), right posterior sectorial duct joining right anterior sectorial duct with an infraportal course (13% vs 4%), right posterior sectorial duct following an infraportal course (23% vs 8%), and left lateral segmental ducts caudal to the umbilical portion of the portal vein (14% vs 3%). The right hepatic duct, which receives all biliary ducts from the right lobe, was significantly less frequently developed in the variation group (46% vs 79%, P < .05). In addition, retroportal bile ducts were seen in four patients with the portal vein variation (P < .05).

CONCLUSION

Bile duct configurations in patients with portal vein variation were significantly different from those in control subjects.

Value of contrast-enhanced magnetic resonance cholangiography in patients undergoing laparoscopic cholecystectomy

Laparoscopic cholecystectomy (LC) is the preferred treatment of symptomatic gallstone disease. Biliary injury during LC is still a serious problem. Knowledge of anatomic detail is important for not encountering the injury. Magnetic resonance cholangiography (MRC) is a noninvasive method for imaging the biliary ducts. However, MRC has many drawbacks such as not showing anatomic structures in detail and respiratory motion. In this study, contrast-enhanced MRC is used to show cystic ducts that are not seen by MRC. Reasons for patient referral for MRC and contrast-enhanced MRC included suspicion of cholecystolithiasis, adenomyomatosis, and gallbladder polyp. Our results show that routine MRC revealed cystic ducts in 38 patients (77.5%) and contrast-enhanced MRC in 46 patients (93.8%). Intraoperative cholangiography (IOC) was taken as gold standard for all patients. We found that contrast-enhanced MRC can provide a useful supplement to MRC in patients with nonvisualized cystic ducts by MRC. To our knowledge, this is the first study of visualization of cystic duct in patients undergoing LC depicted by both MRC and contrast-enhanced MRC.

Bile duct leaks after laparoscopic cholecystectomy: value of contrast-enhanced MRCP

BACKGROUND

We assessed the role of mangafodipir-enhanced magnetic resonance (MR) cholangiography in the detection and location of bile duct leaks after laparoscopic cholecystectomy.

METHODS

In a prospective study, 34 patients with clinical suspicion of bile duct leak after laparoscopic cholecystectomy underwent MR imaging. Our protocol included conventional heavily T2-weighted MR cholangiography and three-dimensional T1-weighted MR cholangiography after an intravenous bolus injection of mangafodipir trisodium. All studies were performed on a 1.5-T or 1-T scanner. Contrast-enhanced MR cholangiograms were evaluated for the presence and location of bile duct leaks. Correlation was obtained in all cases with surgery (n=15), endoscopic retrograde cholangiography (n=5), percutaneous drainage (n=5), and clinical follow-up (n=9).

RESULTS

In 20 of 34 patients, bile duct leakage was proved by surgery, endoscopic retrograde cholangiography, or drainage. Contrast enhancement displayed the leakage in 19 of 20 patients and ruled out leaks in the other 14 patients (95% sensitivity, 100% specificity). The leak site was depicted in 14 patients and contrast-enhanced MR cholangiography successfully located the origin of the leak in 11 patients.

CONCLUSIONS

Contrast-enhanced MR cholangiography with intravenous mangafodipir trisodium can accurately diagnose the presence and location of bile duct leaks in patients who have undergone laparoscopic cholecystectomy.

In vitro CT evaluation of intrahepatic stones: correlation with chemical composition

OBJECTIVE

To describe in vitro CT features of intrahepatic stones and to correlate CT attenuation with chemical composition.

MATERIALS AND METHODS

Of the patients who underwent choledochoscopic intrahepatic stone removal between 1998 and 2001, 54 patients with stones larger than 3 mm were enrolled in this study. In each case, a chemical compositional analysis was performed to determine calcium, cholesterol, total bilirubin, and inorganic phosphorus compositions. The three largest stones obtained from each patient were imaged by CT. CT attenuation numbers were measured in the center images of each stone by drawing free-hand region of interest (ROI). The measured CT attenuation numbers were correlated with their chemical composition. Also, CT attenuation numbers of stones were compared with that of the liver on non-contrast CT (50-70 HU).

RESULTS

Stone size ranged from 3.1 to 10.5 mm (mean +/- S.D.: 6.0 +/- 1.4). The CT attenuation numbers (HU) of stones ranged from 36.4 to 410.19 (mean +/- S.D.: 94.6 +/- 49.9). CT numbers of stones were below 70 HU in 11 patients (20.4%), and below 90 HU in 33 patients (59.3%). The chemical analysis data of the stones were as follows: calcium (0.5-6.5 wt.%; mean +/- S.D., 2.6 +/- 1.4), total bilirubin (0.45-24.4 wt.%; 13.1 +/- 6.2), cholesterol (5.4-73.9 wt.%; 29.3 +/- 17.4), phosphorus (0.1-1.2 wt.%; 0.6 +/- 0.3), and non-soluble residue (17.6-85.4 wt.%; 57.0 +/- 22.6). There was a weak but significant correlation between calcium composition and CT attenuation (r = 0.38, P < 0.01) and no significant correlation between other chemical compositions and the CT attenuation (cholesterol, r = 0.01, P > 0.01; total bilirubin, r = 0.05, P > 0.01; phosphorus, r = 0.01, P > 0.01).

CONCLUSION

On non-contrast CT, intrahepatic stones would not be hyperattenuating with respect to liver parenchyma in about one fifth of patients. The CT attenuation of stones correlates with calcium and does not correlate with any other chemical composition.

Value of contrast-enhanced magnetic resonance cholangiography in patients undergoing laparoscopic cholecystectomy

Laparoscopic cholecystectomy (LC) is the preferred treatment for symptomatic gallstone disease. Biliary injury during LC is still a serious problem. Knowledge of anatomic detail is important for not encountering the injury. Magnetic resonance cholangiography (MRC) is a noninvasive method for imaging the biliary ducts. However, MRC has many drawbacks such as not showing anatomic structures in detail and respiratory motion. In this study, contrast-enhanced MRC was used to show cystic ducts that are not seen on MRC. Reasons for patient referral for MRC and contrast-enhanced MRC included suspicion of cholecystolithiasis, adenomyomatosis, and gallbladder polyp. Our results show that routine MRC revealed cystic ducts in 38 patients (77.5%) and contrast-enhanced MRC in 46 patients (93.8%). Intraoperative cholangiography (IOC) was taken as gold standard for all patients. We found that contrast-enhanced MRC can provide a useful supplement to MRC in patients with cystic ducts not seen on MRC. To our knowledge, this is the first study of visualization of a cystic duct in patients undergoing LC depicted by both MRC and contrast-enhanced MRC.

Preoperative MRI of potential living-donor-related liver transplantation using a single dose of gadobenate dimeglumine

OBJECTIVE

This article evaluates the feasibility of single-dose gadobenate dimeglumine-enhanced MRI as both an angiographic and biliary contrast medium for making a preoperative evaluation of the donor candidates for a living-donor-related liver transplantation.

SUBJECTS AND METHODS

Eleven right hepatic lobe donors underwent MRI examinations using T1- and T2-weighted imaging and T2-weighted MR cholangiography (MRC). The MR angiography (MRA) and contrast-enhanced (CE) T1-weighted MRC images then were obtained after injecting a single dose of gadobenate dimeglumine. One radiologist and one surgeon prospectively reviewed all the MRI examinations for hepatic vascular and biliary abnormalities and compared them with the surgical findings and intraoperative cholangiograms. In addition, two blinded reviewers evaluated the two sets of MRC (T2-weighted MRC set and T2-weighted MRC plus CE-T1-weighted MRC set) retrospectively and recorded the anatomic types of the hilar biliary branching pattern along with their confidence in the interpretation.

RESULTS

Prospective analysis detected the following vascular variants: hepatic arterial variation in two patients, portal venous variation in one, and a significantly large accessory hepatic vein (> 5 mm) in one. Biliary variants also were identified in two patients. All the MRI findings on the vascular and biliary anatomy were corroborated intraoperatively. Retrospective analysis showed that the mean diagnostic confidence in the combined set was significantly higher than that of the T2-weighted MRC alone by both reviewers (p < 0.05).

CONCLUSION

Obtaining both MRA and CE-T1-weighted MRC is feasible using a single dose of gadobenate dimeglumine. Therefore, gadobenate dimeglumine-enhanced MRI might play a role as a preoperative imaging technique for the vascular and biliary evaluation of potential living donors.

Relationship between vascular and biliary anatomy in living liver donors

OBJECTIVE

The objective of our study was to determine whether there is an association between portal venous or hepatic arterial branching patterns (or both) and biliary anatomic variants.

MATERIALS AND METHODS

Two radiologists independently reviewed preoperative hepatic CT scans and intraoperative cholangiograms from 39 consecutive living liver donors. The portal venous and hepatic arterial anatomy was classified on the basis of the preoperative CT scans and the biliary anatomy was classified on the basis the intraoperative cholangiograms into one of two groups: conventional or anomalous. Variables were tested for association using Fisher's exact test.

RESULTS

Anomalous vascular branching variants were common, being present in 23 (59%) of 39 patients. Hepatic arterial anomalies were present in 18 (46%); portal venous anomalies, in seven (18%); and both, in two (5%). Biliary anomalies were present in 15 (38%) of the 39 patients. Of the 23 patients with anomalous vascular anatomy, seven (30%) had biliary anomalies. Of the 16 patients with conventional vascular anatomy, eight (50%) had biliary anomalies. There was no significant association between hepatic arterial anomalies, portal venous anomalies, or the combination of arterial and portal venous anomalies and anomalous biliary drainage.

CONCLUSION

Portal venous and hepatic arterial branching patterns do not correlate well with biliary anatomic variants. In patients with normal hepatic vascular anatomy, biliary anomalies are common.

Blunt trauma of the pancreas and biliary tract: a multimodality imaging approach to diagnosis

Injuries of the pancreas, gallbladder, and bile ducts due to blunt trauma are relatively uncommon and difficult to detect but are associated with high morbidity and mortality, especially if diagnosis is delayed. Accurate and early diagnosis is imperative, and imaging plays a key role in detection. Knowledge of the mechanisms of injury, the types of injuries, and the roles of various imaging modalities is essential for prompt and accurate diagnosis. Early recognition of disruption of the main pancreatic duct is important because such disruption is the principal cause of delayed complications. Computed tomography (CT) can demonstrate pancreatic parenchymal injuries and complications such as abscess, fistula, pancreatitis, and pseudocyst. CT findings can also suggest disruption of the pancreatic duct; however, the ability of CT to indicate this finding depends on the degree of parenchymal injury. Magnetic resonance (MR) cholangiopancreatography allows direct imaging of the pancreatic duct and sites of disruption. Gallbladder injuries can be detected with CT, ultrasonography, hepatobiliary scintigraphy, or MR cholangiopancreatography. CT findings include a collapsed gallbladder, wall thickening, inhomogeneous mural enhancement, and pericholecystic fluid. Bile duct injuries can be suggested with CT, which may show ascites and associated liver injuries, and can be confirmed with hepatobiliary scintigraphy.

Role of magnetic resonance cholangiography in assessing biliary anatomy in right lobe living donors

BACKGROUND

The value of magnetic resonance cholangiography (MRC) in assessing potential adult-to-adult living liver transplant (ALDLT) donors remains poorly defined. The purpose of this study is to determine the accuracy of MRC in assessing biliary anatomy with intraoperative confirmation.

METHODS

A prospective cohort of 30 ALDLT donors who underwent right hepatectomy from October 2000 to July 2003 was evaluated. MRC was performed using a heavily T2 weighted radial slab technique. MRC was interpreted preoperatively by a radiologist and a surgeon and compared with the intraoperative biliary findings in all patients derived from cholangiography (IOC) and bile duct exploration. The sensitivity, specificity, and positive and negative predictive values of MRC for aberrant biliary anatomy were calculated.

RESULTS

MRC suggested normal, aberrant, and indeterminate biliary anatomy in 16, 12, and 2 donors, respectively. IOC revealed normal and aberrant biliary anatomy in 17 and 13 patients, respectively. MRC demonstrated biliary anatomy accurately in 27 of 30 patients. The sensitivity, specificity, positive predictive, and negative predictive values of MRC in detecting aberrant biliary anatomy were 92%, 100%, 100%, and 94%, respectively.

CONCLUSIONS

Preoperative MRC accurately depicts biliary anatomy in potential ALDLT donors and may guide the intraoperative management of the biliary tract.

MR cholangiography with manganese dipyridoxyl diphosphate in the evaluation of biliary-enteric anastomoses: preliminary experience

OBJECTIVE

The purpose of our study was to assess the usefulness of manganese dipyridoxyl diphosphate (Mn-DPDP)-enhanced T1-weighted MR cholangiography for evaluating patients with biliary-enteric anastomoses.

CONCLUSION

Mn-DPDP-enhanced T1-weighted MR cholangiography may provide useful functional information and may aid in the assessment of the patency of biliary-enteric anastomoses.

MR Imaging of the Gallbladder and Biliary System

MR imaging is an established technique for the diagnosis of a spectrum of biliary and gallbladder pathologies and continues to improve with the advent of technologic advances, including new contrast agents and new sequences that are capable of improving upon the contrast resolution and signal-to-noise that are afforded by conventional MR imaging. These improvements already have shown promise for the increasing role of MRC as the initial modality in assessing living liver donors and evaluating post-operative hepato-biliary complications. Improved spatial resolution and the added functional or physiologic information afforded by MR imaging promise ever expanding clinical applicability and usefulness.

Living donor candidates for right hepatic lobe transplantation: evaluation at CT cholangiography--initial experience

PURPOSE

To retrospectively evaluate computed tomographic (CT) cholangiography in the depiction of second-order biliary tract anatomy in living donor candidates for right hepatic lobe transplantation.

MATERIALS AND METHODS

Human research committee approval was obtained, informed consent was not required, and the study was compliant with the Health Insurance Portability and Accountability Act. The authors identified all living right-lobe liver donor candidates who underwent CT cholangiography at their institution between October 2001 (when CT cholangiography was introduced at the institution) and March 2003 (n = 62). There were 41 men (mean age, 36 years; range, 18-55 years) and 21 women (mean age, 40 years; range, 22-55 years). Two readers in consensus rated quality of second-order bile duct visualization at CT cholangiography on a four-point scale (0, not seen; 3, excellent visualization) and noted the presence of variant second-order biliary tract branching anatomy. CT cholangiography findings were compared with those at surgery in subjects who underwent right hepatic lobe retrieval (n = 24). In addition, adult donors who underwent right hepatic lobe retrieval between January 2000 and March 2003 (29 men, mean age, 35 years [range, 20-52 years]; 18 women, mean age, 38 years [range, 23-54 years]) were identified. Numbers of donors who underwent intraoperative cholangiography before and after the introduction of CT cholangiography were compared by using the Fisher exact test.

RESULTS

The mean second-order bile duct score at CT cholangiography was 2.9 (range, 2-3). Of 24 subjects who underwent right lobe retrieval, biliary tract anatomy determined at CT cholangiography was concordant with findings at surgery in 23 (96%). Variant second-order branching anatomy was seen in 13 subjects (54%) at surgery; one variant branch was missed at CT cholangiography. Of 47 subjects who underwent right hepatic lobe retrieval, significantly fewer subjects required conventional intraoperative cholangiography after the introduction of CT cholangiography (three of 24 subjects [12%]) than before (23 of 23 subjects; P < .0001).

CONCLUSION

CT cholangiography accurately depicts biliary tract anatomy in living donor candidates for right hepatic lobe transplantation, and donors who undergo preoperative CT cholangiography are unlikely to need conventional intraoperative cholangiography.

Future directions in body magnetic resonance imaging

Technologic innovations in instrumentation and contrast agents naturally lead to new clinical and research applications in body MRI. Although long-range predictions of innovation are an uncertain process, short-term trends in development are more readily discernable. This review will provide examples of recent developments in magnetic resonance spectroscopic imaging, contrast agent development and molecular imaging, instrumentation, post-processing, and screening in an attempt to describe areas of active research.

Contrast-enhanced magnetic resonance cholangiography using mangafodipir compared with standard T2W MRC sequences: a pictorial essay

Mangafodipir, a manganese-containing hepatobiliary contrast agent, is excreted in bile. We review the principles and practice of a contrast-enhanced MRC technique using mangafodipir and compare it with standard T2-weighted magnetic resonance cholangiography (MRC) sequences. Potential applications include the evaluation of leaks and strictures; the assessment of drainage in normal, surgically by-passed, stented and obstructed biliary systems; the diagnosis of cholecystitis; and the evaluation of normal and variant biliary anatomy.