Volumetric mangafodipir trisodium-enhanced cholangiography to define intrahepatic biliary anatomy

Diagnostic role of magnetic resonance cholangiopancreatography in evaluation of obstructive biliopathies and correlating it with final diagnosis and clinical profile of patients

Aims and Objective:

We assessed the utility of magnetic resonance cholangiopancreatography (MRCP) as a noninvasive diagnostic tool in patients with obstructive biliopathies.

Materials and Methods:

A prospective study was conducted on 54 patients with clinically suspected biliary obstruction. MRCP in these patients was compared and correlated with final diagnosis and their clinical profile.

Statistical Analysis:

Sample profile was described in terms of sensitivity, specificity, positive and negative predictive values, and diagnostic accuracy. Pearson's Chi-square statistics was used to assess the strength of association between diagnostic accuracy of MRCP and final diagnosis.

Results:

Out of the 54 patients, 50 had biliary obstruction. The cause of biliary obstruction was finally identified on the basis of direct cholangiography/surgery/histopathology. In 52 of the 54 patients, MRCP agreed with final diagnosis in identifying the level of block. MRCP agreed with final diagnosis in identifying the cause of obstruction in 48 of the 54 patients (89%). Sensitivity of MRCP in identifying the level of obstruction in comparison with final diagnosis was 100%, while diagnostic accuracy of MRCP in identifying the level of obstruction in comparison with final diagnosis was 96.29%. The correlation between MRCP and final diagnosis in diagnosing cause of obstruction was 0.95 (Pearson's correlation coefficient, P = 0.017).

Conclusion:

MRCP is a safe ionizing radiation and iodinated contrast free modality which has the ability to display the biliary tree by combining the advantages of projectional and cross-sectional imaging.

Combination of increased flip angle, radial k-space trajectory, and free breathing acquisition for improved detection of a biliary variant at living donor liver transplant evaluation using gadoxetic acid-enhanced MRCP

Gadoxetic acid-enhanced magnetic resonance cholangiopancreatography (MRCP) was performed for evaluation of living donor liver transplantation. T2-weighted MRCP and hepatobiliary-phase postcontrast MRCP showed an aberrant right posterior bile duct, although the precise variant was uncertain. Optimized hepatobiliary-phase MRCP was obtained using 3 sequence modifications: increased flip angle to improve contrast between the biliary tree and surrounding tissues; radial k-space sampling to minimize motion artifact; and free-breathing acquisition to improve signal-to-noise ratio and, in turn, spatial resolution (resolution of 1.28 × 1.28 × 1.5 mm). The optimized sequence demonstrated that the right posterior bile duct drained into the cystic duct, consistent with type 3C biliary variant, thus modifying surgical planning.

Magnetic resonance cholangiography in assessing biliary anatomy in living donors: A meta-analysis

AIM: To establish the role of magnetic resonance cholangiography (MRC) in diagnosis of biliary anatomy in living-donor liver transplantation (LDLT) donors.

METHODS: A systematic review was performed by searching electronic bibliographic databases prior to March 2013. Studies with diagnostic results and fulfilled inclusion criteria were included. The methodological quality of the studies was assessed. Sensitivity, specificity and other measures of the accuracy of MRC for diagnosis of biliary anatomy in LDLT donors were summarized using a random-effects model or a fixed-effects model. Summary receiver operating characteristic (SROC) curves were used to summarize overall test performance. Publication bias was assessed using Deek’s funnel plot asymmetry test. Sensitivity analysis was adopted to explore the potential sources of heterogeneity.

RESULTS: Twelve studies involving 869 subjects were eligible to the analysis. The scores of Quality Assessment of Diagnostic Accuracy Studies for the included studies ranged from 11 to 14. The summary estimates of sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, diagnostic OR of MRC in diagnosis of biliary anatomy in LDLT donor were 0.88 (95%CI: 0.84-0.92), 0.95 (95%CI: 0.93-0.97), 15.33 (95%CI: 10.70-21.95), 0.15 (95%CI: 0.11-0.20) and 130.77 (95%CI: 75.91-225.27), respectively. No significant heterogeneity was detected in all the above four measures. Area under SROC curve was 0.971. Little publication bias was noted across the studies (P = 0.557). Sensitivity analysis excluding a study with possible heterogeneity got a similar overall result, which suggested the little influence of this study on the overall results.

CONCLUSION: Our results suggest that MRC is a high specificity but moderate sensitivity technique in diagnosis of biliary anatomy in LDLT donors.

Inaccurate preoperative imaging assessment on biliary anatomy not increases biliary complications after living donor liver transplantation

BACKGROUNDS AND AIMS

Accurate assessment of graft bile duct is important to plan surgical procedure. Magnetic resonance cholangiopancreatography (MRCP) has become an important diagnostic procedure in evaluation of pancreaticobiliary ductal abnormalities and has been reported as highly accurate. We aim to estimate the efficacy of preoperative MRCP on depicting biliary anatomy in living donor liver transplantation (LDLT), and to determine whether inaccurate preoperative imaging assessment would increase the biliary complications after LDLT.

METHODS

The data of 118 cases LDLT were recorded. Information from preoperative MRCP was assessed using intraoperative cholangiography (IOC) as the gold standard. The possible risk factors of recipient biliary complications were analyzed.

RESULTS

Of 118 donors, 84 had normal anatomy (type A) and 34 had anatomic variants (19 cases of type B, 9 cases of type C, 1 case of type E, 2 cases of type F and 3 cases of type I) confirmed by IOC. MRCP correctly predicted all 84 normal cases and 17 of 34 variant cases, and showed an accuracy of 85.6% (101/118). The incidence of biliary complications was comparable between cases with accurate and inaccurate classification of biliary tree from MRCP, and between cases with normal and variant anatomy of bile duct. While cases with graft duct opening ≤5mm showed a significant higher incidence of total biliary complications (21.1% vs. 6.6%, P=0.028) and biliary stricture (10.5% vs. 1.6%, P=0.041) compared with cases with large duct opening >5mm.

CONCLUSION

MRCP could correctly predict normal but not variant biliary anatomy. Inaccurate assessment of biliary anatomy from MRCP not increases the rate of biliary complications, while small-sized graft duct may cause an increase in biliary complications particularly biliary stricture after LDLT.

Hepatobiliary MR imaging with gadolinium-based contrast agents

The advent of gadolinium-based "hepatobiliary" contrast agents offers new opportunities for diagnostic magnetic resonance imaging (MRI) and has triggered great interest for innovative imaging approaches to the liver and bile ducts. In this review article we discuss the imaging properties of the two gadolinium-based hepatobiliary contrast agents currently available in the U.S., gadobenate dimeglumine and gadoxetic acid, as well as important pharmacokinetic differences that affect their diagnostic performance. We review potential applications, protocol optimization strategies, as well as diagnostic pitfalls. A variety of illustrative case examples will be used to demonstrate the role of these agents in detection and characterization of liver lesions as well as for imaging the biliary system. Changes in MR protocols geared toward optimizing workflow and imaging quality are also discussed. It is our aim that the information provided in this article will facilitate the optimal utilization of these agents and will stimulate the reader's pursuit of new applications for future benefit.

Contrast-enhanced MR cholangiography: comparison of Gd-EOB-DTPA and Mn-DPDP in healthy volunteers

OBJECTIVE

The purpose of this study was to compare the biliary enhancement dynamics of gadolinium-ethoxybenzyl-diethylenetriamine-pentaacetic-acid (Gd-EOB-DTPA) and mangafodipir trisodium (Mn-DPDP) for contrast-enhanced MR cholangiography (MRC) in healthy subjects.

METHODS

15 healthy volunteers underwent MRI at 1.5 T with volumetric interpolated breath-hold examination sequence. Each volunteer was scanned once for each contrast agent. The signal-to-noise ratio (SNR) of the liver parenchyma and common hepatic duct (CHD) and the contrast-to-noise ratio (CNR) of CHD to liver parenchyma were evaluated and compared before and at several time points (5, 15, 30, 45, 60, 90, and 120 min) after injection of each agent.

RESULTS

SNR was significantly higher for Gd-EOB-DTPA than for Mn-DPDP in liver parenchyma after 5 min and in CHD after 15 min (p<0.05). CNR of CHD to liver parenchyma using Gd-EOB-DTPA showed an initial decrease at 5 min post-injection followed by a steep increase to a peak at 15 min post-injection. CNR using Mn-DPDP showed a steady increase to a peak at 15 min post-injection without an initial decrease. At 15 min, the value of CNR was significantly higher for Gd-EOB-DTPA than for Mn-DPDP (p<0.05).

CONCLUSION

For both contrast agents, CNR reached a peak at 15 min after contrast injection. At this time point, CNR of Gd-EOB-DTPA was significantly higher than that of Mn-DPDP. Therefore, Gd-EOB-DTPA may provide better contrast-enhanced MRC than Mn-DPDP at 15 min after contrast administration.

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.

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.

Contrast-enhanced MR cholangiography with Gd-EOB-DTPA in patients with liver cirrhosis: visualization of the biliary ducts in comparison with patients with normal liver parenchyma

The purpose of this study was to assess the quality of biliary duct visualization using Gd-EOB-DTPA-enhanced magnetic resonance cholangiography (EOB-MRC) in patients with liver cirrhosis. Forty adult patients with liver cirrhosis (cirrhosis group) and 20 adult individuals with normal liver parenchyma (control group) underwent EOB-MRC using T1-weighted GRE imaging up to 180 min after Gd-EOB-DTPA administration. Two observers assessed the visualization of each biliary structure and the overall anatomical visualization of the biliary tree. Child-Pugh, MELD score and laboratory findings were compared. The grade of visualization for each evaluated biliary structure was statistically different in the two groups (P = 0.004 to <0.001). The overall EOB-MRC quality was rated as sufficient for anatomical visualization of the biliary tree in all individuals of the control group 20 min after Gd-EOB-DTPA application, but in only 16/40 patients (40%) of the cirrhosis group within 30 min after application. Analysis of the ROC curves revealed that the cut-off values, for non-sufficient visualization of the biliary tree 20 min after Gd-EOB-DTPA application, were MELD scores > or =11 and total serum bilirubin levels > or =30 micromol/l. Consecutively, EOB-MRC in patients with liver cirrhosis resulted in a decreased or even non-visualization of the biliary tree in a substantial percentage of patients.

Double common bile duct: curved-planar reformatted computed tomography (CT) and gadobenate dimeglumine-enhanced MR cholangiography

We present the case of a 61-year-old female with double common bile duct (CBD) with an opening into the lesser curvature of the stomach. We discuss the role of curved-planar reformatted computed tomography (CT) and gadobenate dimeglumine (Gd-BOPTA)-enhanced T1-weighted MRI in confirming the diagnosis of this uncommon disease.

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.

Value of manganese-enhanced T1- and T2-weighted MR cholangiography for differentiating cystic parenchymal lesions from cystic abnormalities which communicate with bile ducts

We present a case report to show how manganese-enhanced T1- and T2-weighted MR cholangiography could differentiate cystic parenchymal lesions from cystic abnormalities which communicate with the bile ducts.

[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.

Hepatobiliary MRI: current concepts and controversies

Evaluation of the liver and biliary system is a frequent indication for abdominal MRI. Hepatobiliary MRI comprises a set of noninvasive techniques that are usually very effective in answering most clinical questions. There are significant limitations, however, as well as considerable variation and disagreement regarding the optimal protocols for standard hepatic MRI and magnetic resonance cholangiopancreaticography (MRCP). This review discusses pulse sequences most often used in hepatic MRI and MRCP, examines a few sources of controversy in the current literature, and summarizes some recent and future developments in the field.

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.

Intérêt de l’IRM avec perfusion de mangafodipir trisodium dans la détection des fuites biliaires

PURPOSE

To assess the value of contrast-enhanced magnetic resonance cholangiography with Teslascan perfusion for the detection and localization of trauma-induced and postoperative bile leaks.

MATERIALS AND METHODS

Between October 2002 and December 2004, 7 patients with suspected bile duct leaks after trauma (n = 2) or surgery (n = 5) requiring morphological evaluation were included. MRI examination included single shot fast spin- echo T2 weighted and gradient echo T1 weighted images prior to and 112 minutes in average after IV administration of mangafodipir trisodium. The results of contrast enhanced MR cholangiography were correlated to surgery (n = 3), clinical course (n = 3) and percutaneous drainage (n = 1).

RESULTS

Mangafodipir trisodium-enhanced imaging showed extravasated Teslascan in collections in 6 patients (86%) whereas the combination of T2 weighted images and mangafodipir trisodium enhanced images revealed biliary collections in 7 patients (100%). The fistula between bile duct and collection was visualized in 4 patients (57%) before mangafodipir trisodium perfusion and in 3 patients (43%) after injection. In one patient the fistula was visible only after injection. Combination of both pre- and post injection MR correctly depicted the origin of bile leak in 5 cases (71%).

CONCLUSION

Mangafodipir trisodium-enhanced magnetic resonance cholangiography is a non invasive technique that can successfully detect the presence of bile duct leaks. The combination of T2 weighted MR cholangiography and mangafodipir trisodium-enhanced T1 weighted MR cholangiography increases the sensitivity in detection and localization of the site of bile leak.

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.

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.

Functional MR Cholangiography: Diagnosis of Functional Abnormalities of the Gallbladder and Biliary Tree

OBJECTIVE

Our objective was to describe the technique and utility of functional MR cholangiography (fMRC) in the evaluation of the gallbladder and biliary tree.

CONCLUSION

FMRC has the potential to provide a comprehensive examination for the anatomic and functional assessment of the gallbladder and biliary tree. Complex anatomic abnormalities and functional disorders can be shown by fMRC, including biliary obstruction and extravasation.

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.

Biliary Atresia: Feasibility of Mangafodipir Trisodium–enhanced MR Cholangiography for Evaluation

The study was approved by the institutional review board, and informed consent was obtained from the patients' parents. Twenty-three consecutive infants suspected of having biliary atresia (BA) were prospectively examined by using mangafodipir trisodium (Mn-DPDP)-enhanced magnetic resonance (MR) cholangiography. Sequential T1-weighted spoiled gradient-echo MR cholangiograms were obtained 1, 2, and 3 hours after intravenous administration of Mn-DPDP. The possibility of BA was excluded if bowel excretion of contrast material was noted at contrast material-enhanced MR cholangiography. The diagnostic specificity and accuracy of contrast-enhanced MR cholangiography were compared with those of conventional MR cholangiography, technetium 99m Tc ((99m)Tc)-disofenin (DISIDA) scintigraphy, and the triangular cord sign at ultrasonography (US). MR cholangiography was used to accurately distinguish four cases of BA from 19 cases of other cholestatic liver diseases, without false-positive results. Conventional MR cholangiography, (99m)Tc-DISIDA scintigraphy, and the triangular cord sign at US respectively yielded false-positive results of 42% (eight of 19 infants), 35% (six of 17 infants), and 11% (two of 19 infants) in patients without BA. Mn-DPDP-enhanced MR cholangiography appears to be a promising modality for early diagnosis of BA as the cause of neonatal cholestasis.

Early biliary complications of laparoscopic cholecystectomy: evaluation on T2-weighted MR cholangiography in conjunction with mangafodipir trisodium-enhanced 3D T1-weighted MR cholangiography

OBJECTIVE

Our aim was to assess preliminary experience with combined conventional T2-weighted and mangafodipir trisodium (MnDPDP)-enhanced T1-weighted MR cholangiography in evaluating early biliary complications of laparoscopic cholecystectomy.

SUBJECTS AND METHODS

Conventional heavily T2-weighted MR cholangiography with MnDPDP-enhanced T1-weighted MR cholangiography and ERCP were performed in seven patients with high clinical suspicion of biliary complications after laparoscopic cholecystectomy. The final diagnoses of complications were classified according to the presence and degree of bile duct injury, bile leakage, and retained stones.

RESULTS

The diagnoses on MR cholangiography were as follows: complete transection and occlusion of the common bile duct with bile leakage (n = 3), partial strictures of the common bile duct with bile leakage (n = 1), cystic duct leakage (n = 1), partial ligation of an aberrant right hepatic duct (n = 1), and hemorrhage without biliary complication (n = 1). The final diagnoses at surgery (n = 2) and ERCP (n = 5) were as follows: complete transection and occlusion of the common bile duct with bile leakage (n = 2), partial strictures of the common bile duct with bile leakage (n = 2), cystic duct leakage (n = 1), partial ligation of an aberrant right hepatic duct (n = 1), and hemorrhage without biliary complication (n = 1). MR cholangiography accurately yielded the same findings as the final diagnoses, except in one case with partial stricture of the bile duct with bile leakage (overdiagnosed as complete occlusion on MR cholangiography).

CONCLUSION

Combined conventional T2-weighted and MnDPDP-enhanced T1-weighted MR cholangiography may eliminate the use of other studies for the imaging of biliary complications after cholecystectomy if this preliminary data can be verified in a larger study.

Concordance of second-order portal venous and biliary tract anatomies on MDCT angiography and MDCT cholangiography

OBJECTIVE

We sought to investigate the concordance between second-order portal venous and biliary tract anatomies using MDCT angiography and MDCT cholangiography.

MATERIALS AND METHODS

We retrospectively identified 56 living related potential liver donors who underwent both MDCT angiography and MDCT cholangiography. Two reviewers independently rated axial images and 3D reconstructions of MDCT angiograms and cholangiograms as diagnostic or nondiagnostic with respect to depiction of second-order portal venous and biliary tract anatomies. In images rated as diagnostic, second-order portal venous and biliary tract anatomies were categorized as conventional or variant. The concordance between portal venous and biliary tract anatomies was analyzed using McNemar exact chi-square test.

RESULTS

All examinations were diagnostic. Second-order portal venous variants were seen in 10 (18%) and biliary branch variants were seen in 23 (41%) of the 56 patients. Patients with variant portal venous anatomy (6/10, 60%) were more likely to have variant biliary tract anatomy than patients with conventional portal venous anatomy (17/46, 37%; p < 0.01). The sensitivity of variant portal venous anatomy as a marker for variant biliary anatomy was 26% (6/23 patients).

CONCLUSION

Concordance between second-order portal venous and biliary tract anatomies is statistically significant. However, in our series, a number of patients with conventional portal venous anatomy had variant biliary anatomy; therefore, the finding of conventional portal venous anatomy does not obviate preoperative biliary tract imaging in patients before liver donation.

Value of MR Cholangiography in Patients with Iatrogenic Bile Duct Injury After Cholecystectomy

OBJECTIVE

Our aim was to determine the diagnostic role of MR cholangiography in the evaluation of iatrogenic bile duct injuries after cholecystectomy.

SUBJECTS AND METHODS

Nineteen patients (14 women and five men; mean age, 47 years; age range, 24-75 years) with suspected bile duct injury as a result of laparoscopic cholecystectomy (17 patients) and open cholecystectomy (two patients) underwent MR cholangiography. MR images were evaluated for bile duct discontinuity, presence or absence of biliary dilation, stricture, excision injury, free fluid, and collections. Bile duct excision and stricture were classified according to the Bismuth classification. Final diagnosis was made on the basis of findings at surgery in 15 patients, on percutaneous transhepatic cholangiography (PTC) in one patient, and on endoscopic retrograde cholangiography (ERC) and at clinical follow-up until hospital discharge in the remaining three patients.

RESULTS

In 16 patients, injury of the bile duct was observed. Two patients had Bismuth type I injury; one patient, type II injury; 11 patients, type III injury; and one patient each, type IV and V injuries. Three patients showed findings suggestive of leakage from the cystic duct remnant, which were confirmed on ERC.

CONCLUSION

MR cholangiography is an accurate diagnostic technique in the identification of postoperative bile duct injuries. This technique allows exploration above and below the level of obstruction, a resource provided by neither ERC nor PTC, and allows the accurate classification of these injuries, which is essential for treatment planning.

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.

Preoperative evaluation of biliary anatomy in adult live liver donors with volumetric mangafodipir trisodium enhanced magnetic resonance cholangiography

Accurate preoperative depiction of biliary anatomy is not always adequately accomplished by imaging techniques in living donor liver transplantation (LDLT). We present the results of a prospective study designed to evaluate the ability of mangafodipir trisodium (Mn-DPDP)-enhanced magnetic resonance (MR) cholangiography (MRC) for this purpose in a series of 25 adult living liver donors (LLDs). We also analyze if a simple or a more complex surgical procedure can be preoperatively suggested for biliary reconstruction in the recipients. Findings on MRC were compared with operative cholangiography (OC). A conventional distribution with a right hepatic duct (RHD) longer than 1 cm anticipated a simple procedure (duct-to-duct anastomosis or hepaticojejunostomy [HJ]). A shorter RHD or any variant were predictors of a more complex surgery (bench ductoplasty or multiple anastomoses). Agreement between MRC and OC in assessing the biliary anatomy was measured using the kappa statistic, and differences between the kind of surgery predicted at MRC and the biliary anastomosis performed were evaluated with Fisher's exact test. Normal variants were present in 16 / 25 donors (64%). MRC was accurate in depicting the pattern of bile duct distribution observed at OC in 22 / 25 (88%) donors (kappa = .831), and correctly predicted the complexity of biliary anastomosis in the recipient in 22 / 25 (88%) donors. No significant differences were observed between complexity of biliary surgery proposed at MRC and the final surgery performed (P = .002). In conclusion, Mn-DPDP-enhanced MRC is highly accurate in depicting the biliary duct anatomy and can be used preoperatively for surgical planning in LDLT.

Defining intrahepatic biliary anatomy in living liver transplant donor candidates at mangafodipir trisodium-enhanced MR cholangiography versus conventional T2-weighted MR cholangiography

PURPOSE

To compare three-dimensional (3D) mangafodipir trisodium-enhanced T1-weighted magnetic resonance (MR) cholangiography with conventional T2-weighted MR cholangiography for depiction and definition of intrahepatic biliary anatomy in liver transplant donor candidates.

MATERIALS AND METHODS

One hundred eight healthy liver transplant donor candidates were examined with two MR cholangiographic methods. All candidates gave written informed consent, and the study was approved by the institutional review board. First, breath-hold transverse and coronal half-Fourier single-shot turbo spin-echo and breath-hold oblique coronal heavily T2-weighted turbo spin-echo sequences were performed. Second, mangafodipir trisodium-enhanced breath-hold fat-suppressed 3D gradient-echo sequences were performed through the ducts (oblique coronal plane) and through the entire liver (transverse plane). Interpretation of biliary anatomy findings, particularly variants affecting right liver lobe biliary drainage, and degree of interpretation confidence at both 3D mangafodipir trisodium-enhanced MR cholangiography and T2-weighted MR cholangiography were recorded and compared by using the Wilcoxon signed rank test. Then, consensus interpretations of both MR image sets together were performed. Intraoperative cholangiography was the reference-standard examination for 51 subjects who underwent right lobe hepatectomy. The McNemar test was used to compare the accuracies of the individual MR techniques with that of the consensus interpretation of both image sets together and to compare each technique with intraoperative cholangiography.

RESULTS

Biliary anatomy was visualized with mangafodipir trisodium enhancement in all patients. Mangafodipir trisodium-enhanced image findings agreed with findings seen at combined interpretations significantly more often than did T2-weighted image findings (in 107 [99%] vs 88 [82%] of 108 donor candidates, P < .001). Confidence was significantly higher with the mangafodipir trisodium-enhanced images than with the T2-weighted images (mean confidence score, 4.5 vs 3.4; P < .001). In the 51 candidates who underwent intraoperative cholangiography, mangafodipir trisodium-enhanced imaging correctly depicted the biliary anatomy more often than did T2-weighted imaging (in 47 [92%] vs 43 [84%] donor candidates, P = .14), whereas the two MR imaging techniques combined correctly depicted the anatomy in 48 (94%) candidates.

CONCLUSION

Mangafodipir trisodium-enhanced 3D MR cholangiography depicts intrahepatic biliary anatomy, especially right duct variants, more accurately than does conventional T2-weighted MR cholangiography.

Imaging of the complications of laparoscopic cholecystectomy

Laparoscopic cholecystectomy has, in recent years, emerged as the gold standard therapeutic option for the management of uncomplicated symptomatic cholelithiasis. Each year, up to 700,000 of these procedures are performed in the United States alone. While the relative rate of post-procedural complications is low, the popularity of this method of gallbladder removal is such that this entity is not uncommonly clinically encountered, and therefore must be borne in mind by the investigating physician. By way of pictorial review, we explore the radiological appearances of a variety of potential complications of laparoscopic cholecystectomy. The radiological appearances of each shall be illustrated in turn using several imaging modalities, including ultrasound, computed tomography, MR cholangiography and radio-isotope scintigraphy. From calculus retention to portal vein laceration, bile duct injury to infected dropped calculi, we illustrate numerous potential complications of this procedure, as well as indicating the most suitable imaging modalities available for the detection of these adverse outcomes. As one of the most commonly performed intra-abdominal surgeries, laparoscopic cholecystectomy and the complications thereof are not uncommonly encountered. Awareness of the possible presence of these numerous complications, including their radiological appearances, makes early detection more likely, with resultant improved patient outcome.

Diagnosing biliary complications of orthotopic liver transplantation with mangafodipir trisodium-enhanced MR cholangiography: comparison with conventional MR cholangiography

OBJECTIVE

This study was designed to determine whether the addition of mangafodipir trisodium-enhanced MRI could improve the image quality, visualization of ductal structures, and diagnostic confidence provided by conventional T2-based MR cholangiography (MRC) in patients with suspected biliary complications after orthotopic liver transplantation. SUBJECTS AND METHODS. Our study group consisted of 25 consecutive patients who were referred for MR evaluation of clinically suspected biliary complications after orthotopic liver transplantation. Conventional MRC in the axial and coronal planes was performed in each patient, followed by fat-suppressed volumetric gradient-echo imaging in the same planes both before and after the IV administration of mangafodipir trisodium. Imaging was performed in all patients until the contrast agent was seen in the bowel. Images were then graded for quality, visualization of bile ducts and anastomoses, presence of significant stricture or leak, and level of diagnostic confidence.

RESULTS

Mangafodipir trisodium-enhanced MRC tended to outperform conventional MRC in overall image quality and extrahepatic duct visualization; it was also more effective in delineating biliary anastomoses, and the difference was statistically significant (p < 0.001). All 25 enhanced examinations were considered diagnostic. Diagnostic confidence was scored as poor or lacking in 14 of the conventional MRC examinations for biliary stenosis and in 12 examinations for biliary leak.

CONCLUSION

Enhancement with mangafodipir trisodium improves the performance of MRC for the detection and exclusion of biliary abnormalities after orthotopic liver transplantation. Future investigations should compare the performance of mangafodipir trisodium-enhanced MRC with the performance of more invasive techniques.

Liver transplant donor candidates: associations between vascular and biliary anatomic variants

Our objective was to investigate the coexistence of vascular and biliary anatomic variants, the latter of which are known to increase the risk of biliary complications in living liver donor transplantation. A total of 108 consecutive liver donor candidates were examined by magnetic resonance (MR) imaging that included 2 MR cholangiography methods, T2-weighted MR cholangiography and mangofodipir-enhanced T1-weighted three-dimensional (3D) MR cholangiography, as well as gadolinium-enhanced MR angiography and venography of the liver. Images were interpreted by at least 2 investigators in consensus for definition of hepatic arterial, portal venous, and biliary anatomy. A subset of 51 subjects underwent laparotomy for right hepatectomy. Of the 108 subjects examined, 50 (46%) demonstrated normal hepatic artery, portal vein, and biliary anatomy. Variants of the hepatic artery were found in 27 of 108 (25%) subjects, of the portal vein in 12 of 108 (11%) subjects, and of the bile ducts in 30 of 108 (28%) subjects. Of the 27 subjects with hepatic arterial variants, 8 (30%) also had variant biliary anatomy. The association between hepatic arterial variants and biliary variants was not statistically significant (P >.5). However, of the 12 subjects with portal vein variants, 7 (58%) had biliary variants, and in 6 of 7 cases, the right posterior hepatic duct was anomalous. By chi-square analysis, the association between portal venous and biliary variants was significant (P =.012). In conclusion, over half of subjects with portal vein variants were found to have anomalous biliary anatomy, which always involved the hepatic ducts of the right lobe. The association between portal venous and biliary variants is statistically significant, while there is no significant association between hepatic arterial and biliary variants.

MR Imaging of the Stomach: Potential Use for Mangafodipir Trisodium— A Study in Swine

PURPOSE

To evaluate mangafodipir trisodium as a potential contrast agent at magnetic resonance (MR) imaging of the stomach.

MATERIALS AND METHODS

Mangafodipir trisodium was injected intravenously into three swine at a dose of 5 micromol per kilogram of body weight. For comparison, gadopentetate dimeglumine was injected into three other swine at a dose of 0.1 mmol per kilogram of body weight. T1-weighted three-dimensional MR images were acquired in all six swine at 1.5 T before and approximately 10, 15, 20, 25, 30, and 40 minutes after contrast material administration. Extracted stomach specimens were imaged at 3.0 T. In vivo and ex vivo images were evaluated visually and quantitatively for contrast enhancement of the stomach, and in vivo images were evaluated for the presence of reflux from the duodenum.

RESULTS

Mangafodipir trisodium produced prolonged and selective enhancement of the inner surface of the stomach, in contrast to the more general enhancement seen with gadopentetate dimeglumine, and reflux from the duodenum could not account for this selective enhancement. Ex vivo images confirmed that T1 enhancement in the stomach wall with mangafodipir trisodium was limited to the inner surface. Gadopentetate dimeglumine did not produce selective enhancement of the inner surface of the stomach.

CONCLUSION

Mangafodipir trisodium preferentially enhances the inner surface of the stomach on MR images acquired in swine and, therefore, may have potential for use as a contrast agent at MR imaging of the human stomach.

The utility of MRCP in preoperative mapping of biliary anatomy in adult-to-adult living related liver transplant donors

PURPOSE

To assess the utility of magnetic resonance cholangiopancreatography (MRCP) in preoperative mapping of biliary anatomy in adult-to-adult living related liver transplant (LRLT) donors.

MATERIALS AND METHODS

From 57 potential donors with preoperative MRCP, 27 cases (16 men, 11 women, age range 22-51 years, mean 37.2 years) underwent right lobe resection and had intraoperative cholangiography (IOC) for comparison. The MRCP and IOC reports were retrospectively reviewed in all 27 cases. The MRCP was performed on 1.5 Tesla MR magnets using breath-hold heavily T2-weighted sequences in axial/coronal thin sections, and variable-thickness rotating slabs. The accuracy of preoperative MRCP for biliary mapping in potential LRLT donors was analyzed compared to the IOC findings.

RESULTS

Of 27 donors, 26 (96.3%) had MRCP which showed adequate information of central intrahepatic biliary anatomy. Of these, 19 had normal bifurcation confirmed by IOC, and single biliary anastomosis was created in the recipient at transplantation. MRCP correctly predicted 17 of 19 normal cases (sensitivity for normals: 89.5%). In seven donors with variant biliary anatomy, two separate biliary anastomoses were performed in the recipient. MRCP correctly predicted five of seven variants (sensitivity for variants: 71.4%). Overall, MRCP had an accuracy 84.6% (22/26).

CONCLUSIONS

MRCP has potential in the preoperative assessment of nondilated bile ducts in LRLT donors, however further improvements are desired to increase its quality and accuracy.

Mangafodipir-enhanced magnetic resonance cholangiography for the diagnosis of bile duct leaks

BACKGROUND

The purpose of this prospective study was to assess the value of contrast-enhanced magnetic resonance cholangiography with mangafodipir trisodium perfusion for detection and localization of trauma-induced and postoperative bile duct leaks.

METHODS

Eleven patients with suspected bile duct leaks after trauma (n=5) or surgery (n=6) were included. Patients with suspected leaks after cholecystectomy were excluded. All patients underwent contrast-enhanced magnetic resonance cholangiography with two-dimensional axial and three-dimensional coronal gradient-echo images acquired 1 to 3 hours after intravenous administration of mangafodipir trisodium perfusion. Contrast-enhanced magnetic resonance cholangiography findings were correlated with direct cholangiography obtained in all patients, including endoscopic retrograde (n=7) and percutaneous transhepatic cholangiography (n=4).

RESULTS

Biliary tract enhancement was identified in all patients on contrast-enhanced magnetic resonance cholangiography. Peritoneal cavity fluid and bile collections that contained extravasated mangafodipir trisodium (increased signal intensity on gradient-echo sequences) were demonstrated in 6 patients. Direct cholangiography confirmed the presence of bile duct leaks in these 6 patients and the absence of bile duct leaks in 5 patients. There was no false-negative or false-positive contrast-enhanced magnetic resonance cholangiography.

CONCLUSIONS

Mangafodipir-enhanced magnetic resonance cholangiography is a noninvasive technique that can provide functional biliary information with excellent depiction of bile duct leaks.

Biliary tract depiction in living potential liver donors: comparison of conventional MR, mangafodipir trisodium-enhanced excretory MR, and multi-detector row CT cholangiography--initial experience

PURPOSE

To compare biliary tract depiction in living potential liver donors at conventional magnetic resonance (MR), mangafodipir trisodium-enhanced excretory MR, and multi-detector row computed tomographic (CT) cholangiography.

MATERIALS AND METHODS

Eight living potential liver donors underwent iodipamide meglumine-enhanced CT cholangiography. Eight different potential liver donors then underwent conventional MR cholangiography and mangafodipir trisodium-enhanced excretory MR cholangiography. Two readers independently scored all first-, second-, and third-order biliary branches with a four-point scale from 0 (not seen) to 3 (excellent visualization). Interobserver agreement was calculated by using the weighted kappa statistic. Scores were compared between imaging modalities by using generalized estimating equations. Imaging findings of second-order biliary tract anatomy were compared with intraoperative findings for nine patients.

RESULTS

Interobserver agreement for overall biliary tract visualization was good for CT, conventional MR, and excretory MR cholangiography (with weighted kappa values of 0.76, 0.66, and 0.79, respectively). The mean second-order biliary branch visualization scores for readers 1 and 2, respectively, were significantly higher at CT cholangiography (2.81 and 2.75) than at conventional MR (1.84 and 1.75, P <.001), excretory MR (2.00 and 2.06, P <.001), and combined conventional and excretory MR cholangiography (2.31 and 2.25, P <.01). At CT, conventional MR, and excretory MR cholangiography, respectively, second-order biliary branching anatomy was discernible in eight, five, and seven patients, with second-order biliary branch variants seen in three, two, and two patients. Surgical findings confirmed the pattern of second-order biliary branching seen at CT in five patients, that seen at conventional MR imaging in one patient, and that seen at excretory MR cholangiography in three patients. At surgery, one case of variant biliary anatomy was found to have been missed at CT cholangiography.

CONCLUSION

In living potential liver donors, CT cholangiography enables significantly better biliary tract visualization than conventional or excretory MR cholangiography either alone or in combination.

Hepatobiliary contrast agents for contrast-enhanced MRI of the liver: properties, clinical development and applications

Hepatobiliary contrast agents with uptake into hepatocytes followed by variable biliary excretion represent a unique class of cell-specific MR contrast agents. Two hepatobiliary contrast agents, mangafodipir trisodium and gadobenate dimeglumine, are already clinically approved. A third hepatobiliary contrast agent, Gd-EOB-DTPA, is under consideration. The purpose of this review is to provide an overview on the properties, clinical development and application of these three hepatobiliary contrast agents. Bolus injectable paramagnetic hepatobiliary contrast agents combine established features of extracellular agents with the advantages of hepatocyte specificity. The detection and characterisation of focal liver disease appears to be improved compared to unenhanced MRI, MRI with unspecific contrast agents and contrast-enhanced CT. To decrease the total time spent by a patient in the MR scanner, it is advisable to administer the agent immediately after acquisition of unenhanced T1-w MRI. After infusion or bolus injection (with dynamic FS-T1-w 2D or 3D GRE) of the contrast agent, moderately and heavily T2w images are acquired. Post-contrast T1-w MRI is started upon completion of T2-w MRI for mangafodipir trisodium and Gd-EOB-DTPA as early as 20 min following injection, while gadobenate dimeglumine scans are obtained >60 min following injection. Post-contrast acquisition techniques with near isotropic 3D pulse sequences with fat saturation parallel the technical progress made by MSCT combined with an unparalleled improvement in tumour-liver contrast. The individual decision that hepatobiliary contrast agent one uses is partly based on personal preferences. No comparative studies have been conducted comparing the advantages or disadvantages of all three agents directly against each other.

Functional magnetic resonance cholangiography (fMRC) of the gallbladder and biliary tree with contrast-enhanced magnetic resonance cholangiography

PURPOSE

To determine the diagnostic performance of functional magnetic resonance cholangiography (fMRC) for the evaluation of anatomic and functional biliary disorders.

MATERIALS AND METHODS

At 1.5 T, 39 MR examinations with conventional MRC and mangafodipir trisodium-enhanced fMRC were retrospectively reviewed by three observers who recorded anatomic (duct dilation, stricture, filling defects) and functional (cholecystitis, obstruction) abnormalities in three modes: MRC alone, fMRC alone, and MRC and fMRC images together (combined-MRC). Performance was determined by comparing findings with each mode to findings of invasive cholangiography (IC) and surgery.

RESULTS

Among 75 biliary segments (correlated with IC), the sensitivity/specificity for diagnosing dilation (N = 41) with MRC was 95%/97%; with fMRC, 90%/100%; with combined-MRC, 100%/97%. For stricture (N = 7), the sensitivity/specificity of MRC was 86%/98%; of fMRC, 43%/100%; of combined-MRC, 86%/100%. For filling defects (N = 9), the sensitivity/specificity of MRC was 91%/98%; of fMRC, 82%/100%; of combined-MRC, 91%/100%. For diagnosing obstruction (N = 9), the sensitivity/specificity of MRC, fMRC, and combined-MRC were 89%/100%, 100%/100%, and 100%/100%, respectively. For surgically proven cholecystitis (N = 13), positive predictive values for diagnosing acute/chronic cholecystitis for MRC were 33%/40%; for fMRC, 100%/50%; for combined-MRC, 100%/50%.

CONCLUSION

Although single-shot fast spin echo (SSFSE)-MRC is valuable, the addition of fMRC increased diagnostic performance for functional biliary disorders.