Early phase detection of bile leak after hepatobiliary surgery: value of Gd-EOB-DTPA-enhanced MR cholangiography

Cross-sectional imaging after pancreatic surgery: The dialogue between the radiologist and the surgeon

Pancreatic surgery is nowadays considered one of the most complex surgical approaches and not unscathed from complications. After the surgical procedure, cross-sectional imaging is considered the non-invasive reference standard to detect early and late compilations, and consequently to address patients to the best management possible. Contras-enhanced computed tomography (CECT) should be considered the most important and useful imaging technique to evaluate the surgical site. Thanks to its speed, contrast, and spatial resolution, it can help reach the final diagnosis with high accuracy. On the other hand, magnetic resonance imaging (MRI) should be considered as a second-line imaging approach, especially for the evaluation of biliary findings and late complications. In both cases, the radiologist should be aware of protocols and what to look at, to create a robust dialogue with the surgeon and outline a fitted treatment for each patient.

Magnetic Resonance Cholangiography Diagnosing Post-cholecystectomy Biliary Injuries

OBJECTIVE

This study aimed to determine the diagnostic performance of contrasted magnetic resonance cholangiography for detecting bile duct lesions following cholecystectomy.

MATERIALS AND METHODS

A retrospective case series study was conducted that included patients over 18 years of age with suspected bile duct injury after cholecystectomy, who underwent contrasted magnetic resonance cholangiography, and who also had endoscopic retrograde cholangiopancreatography, surgery, or subsequent clinical follow-up. The images were interpreted by two radiologists who assigned the type of lesion according to the Strasberg classification. Qualitative variables were represented by frequencies and proportions, while quantitative variables were described using measures of central tendency and dispersion. Sensitivity, specificity, and predictive values were assessed, along with interobserver variability, using the kappa index.

RESULTS

We included 20 patients with a median age of 51.5 years (interquartile range: 35), and 14 (70%) were women. In all 20 patients, lesions were identified on magnetic resonance cholangiography, of which 19 were confirmed with the gold standard for a positive predictive value of 100% (hepatobiliary-specific contrast agents) and 92% (extracellular contrast). The most frequent lesions were Strasberg E2 and E4 in five patients each. The kappa index was 1 in determining the presence or absence of bile duct injury and 0.9 in the Strasberg classification.

CONCLUSION

Contrasted magnetic resonance cholangiography is a method with high positive predictive value and almost perfect interobserver agreement for diagnosing bile duct lesions after cholecystectomy.

Imaging of hepato-pancreato-biliary emergencies in patients with cancer

Hepato-pancreato-biliary (HPB) emergencies in patients with cancer encompass an extensive array of various conditions, including primary malignancies that require prompt treatment, associated severe complications, and life-threatening consequences arising from treatment. In patients with cancer, the liver can be affected by chemotherapy-induced hepatotoxicity, veno-occlusive disease, Budd-Chiari syndrome, liver hemorrhage, and other complications arising from cancer therapy with all these complications requiring timely diagnosis and prompt treament. Cholecystitis induced by systemic anticancer therapies can result in severe conquences if not promptly identified and treated. The application of immunotherapy in cancer therapy is associated with cholangitis. Hemobilia, often caused by medical interventions, may require arterial embolization in patients with severe bleeding and hemodynamic instability. Malignant biliary obstruction in patients with biliary cancers may necessitate palliative strategies such as biliary stenting. In pancreatic cancer, patients often miss surgical treatment due to advanced disease stages or distant metastases, leading to potential emergencies at different treatment phases. This comprehensive review underscores the complexities of diagnostic and treatment roles of medical imaging in managing HPB emergencies in patients with cancer. It illustrates the crucial role of imaging techniques, including magnetic resonance imaging, computed tomography and ultrasound, in diagnosing and managing these conditions for timely intervention. It provides essential insights into the critical nature of early diagnosis and intervention in cancer-related HPB emergencies, ultimately impacting patient outcomes and survival rates.

Gd-EOB-DTPA-MRCP to localize bile leakage after liver trauma and surgery: impact on treatment and outcome

OBJECTIVES

Bile leakage (BL) is a challenging complication after hepatobiliary surgery and liver trauma. Gadolinium ethoxybenzyl (Gd-EOB-DTPA)-enhanced magnetic resonance cholangiopancreatography (MRCP) is used to diagnose BL non-invasively. We assessed the value of Gd-EOB-DTPA-MRCP in the detection of postoperative and post-traumatic BL hypothesizing that exact identification of the leakage site is pivotal for treatment planning and outcome.

METHODS

We retrospectively enrolled 39 trauma and postoperative patients who underwent Gd-EOB-DTPA-MRCP for suspected BL. Three readers rated the presence of BL and leakage site (intraparenchymal, central, peripheral ± aberrant or disconnected ducts). Imaging findings were compared to subsequent interventional procedures and their complexity and outcome.

RESULTS

BL was detected in Gd-EOB-DTPA-MRCP in 25 of patients and was subsequently confirmed. Sites of BL differed significantly between postoperative (central [58%] and peripheral [42%]) and trauma patients (intraparenchymal [100%]; p < 0.001). Aberrant or disconnected ducts were diagnosed in 8%/26% of cases in the postoperative subgroup. Inter-rater agreement for the detection and localization of BL was almost perfect (Κ = 0.85 and 0.88; p < 0.001). Intraparenchymal BL required significantly less complex interventional procedures (p = 0.002), whereas hospitalization and mortality did not differ between the subgroups (p > 0.05).

CONCLUSIONS

Gd-EOB-DTPA-MRCP reliably detects and exactly locates BL in postoperative and trauma patients. Exact localization of biliary injuries enables specific treatment planning, as intraparenchymal leakages, which occur more frequently after trauma, require less complex interventions than central or peripheral leaks in the postoperative setting. As a result of specific treatment based on exact BL localization, there was no difference in the duration of hospitalization or mortality.

CLINICAL RELEVANCE STATEMENT

Gd-EOB-DTPA-MRCP is a reliable diagnostic tool for exactly localizing iatrogenic and post-traumatic biliary leakage. Its precise localization helps tailor local therapies for different injury patterns, resulting in comparable clinical outcomes despite varying treatments.

KEY POINTS

• Gd-EOB-DTPA-MRCP enables adequate detection and localization of bile leakages in both postoperative and post-traumatic patients. • The site of bile leakage significantly impacts the complexity of required additional interventions. • Intraparenchymal bile leakage is commonly seen in patients with a history of liver trauma and requires less complex interventions than postoperative central or peripheral bile leakages, while hospitalization and mortality are similar.

Gadoxetic acid (Primovist®) beyond the characterization of hepatic lesions in MRI: the case of biliary leaks

Gadoxetic acid (Primovist®) is a paramagnetic contrast agent widely known for its use in the characterisation of focal liver lesions; however, it is also an important tool for the evaluation of the biliary tract. Its hepatospecific properties are able to demonstrate the presence and location of biliary leaks by MRI, allowing appropriate treatment planning and avoiding unnecessary invasive tests.

Biliary complications after liver transplantation: A computed tomography and magnetic resonance imaging pictorial review

Biliary complications are the most common complications after liver transplantation. Computed tomography (CT) and magnetic resonance imaging (MRI) are cornerstones for timely diagnosis of biliary complications after liver transplantation. The diagnosis of these complications by CT and MRI requires expertise, mainly with respect to identifying subtle early signs to avoid missed or incorrect diagnoses. For example, biliary strictures may be misdiagnosed on MRI due to size mismatch of the common ducts of the donor and recipient, postoperative edema, pneumobilia, or susceptibility artifacts caused by surgical clips. Proper and prompt diagnosis of biliary complications after transplantation allows the timely initiation of appropriate management. The aim of this pictorial review is to illustrate various CT and MRI findings related to biliary complications after liver transplantation, based on time of presentation after surgery and frequency of occurrence.

Liver-Specific Contrast-Enhanced Magnetic Resonance Cholangio-Pancreatography (Ce-MRCP) in Non-Invasive Diagnosis of Iatrogenic Biliary Leakage

Current non-invasive diagnostic modalities of iatrogenic bile leak (BL) are not particularly sensitive and often fail to localise the BL origin. Percutaneous transhepatic cholangiography (PTC) and endoscopic retrograde cholangiopancreatography (ERCP) are considered the gold standard, yet are invasive studies with potential complications. Ce-MRCP has been not comprehensively studied in this setting but may prove particularly helpful given its non-invasive nature and the anatomical dynamic detail. This paper reports a monocentric retrospective study of BL patients referred between January 2018 and November 2022 submitted to Ce-MRCP followed by PTC. The primary outcome was the accuracy of Ce-MRCP in detecting and localising BL compared to PTC and ERCP. Blood tests, coexisting cholangitis features and time for leak resolution were also investigated. Thirty-nine patients were included. Liver-specific contrast-enhanced MRCP detected BL in 69% of cases. The BL localisation was 100% accurate. Total bilirubin above 4 mg/dL was significantly associated with false negative results of Ce-MRCP. Ce-MRCP is highly accurate in detecting and localising BL, but sensitivity is significantly reduced by a high bilirubin level. Ce-MRCP may be very useful in early BL diagnosis and in accurate pre-treatment planning, but can only be reliably used in selected patients with TB < 4 mg/dL. Non-surgical techniques, both radiological and endoscopic, are proven to be effective in terms of leak resolution.

Imaging Features of Main Hepatic Resections: The Radiologist Challenging

Liver resection is still the most effective treatment of primary liver malignancies, including hepatocellular carcinoma (HCC) and cholangiocarcinoma (CCA), and of metastatic disease, such as colorectal liver metastases. The type of liver resection (anatomic versus non anatomic resection) depends on different features, mainly on the type of malignancy (primary liver neoplasm versus metastatic lesion), size of tumor, its relation with blood and biliary vessels, and the volume of future liver remnant (FLT). Imaging plays a critical role in postoperative assessment, offering the possibility to recognize normal postoperative findings and potential complications. Ultrasonography (US) is the first-line diagnostic tool to use in post-surgical phase. However, computed tomography (CT), due to its comprehensive assessment, allows for a more accurate evaluation and more normal findings than the possible postoperative complications. Magnetic resonance imaging (MRI) with cholangiopancreatography (MRCP) and/or hepatospecific contrast agents remains the best tool for bile duct injuries diagnosis and for ischemic cholangitis evaluation. Consequently, radiologists should be familiar with the surgical approaches for a better comprehension of normal postoperative findings and of postoperative complications.

Indocyanine green fluorescence imaging as an adjunct for the localization of a bile leak after split liver transplantation

BACKGROUND

The intraoperative identification of a bile leak after liver transplantation can be challenging, especially when using technical variant grafts. Possible sources of leakage include the sometimes multiple biliary anastomoses or orphan ducts leading to cut surface leak. Preoperative imaging is often unable to precisely identify the location of the leak. Indocyanine green (ICG) fluorescence imaging has been utilized in adult hepatobiliary and transplant surgery, but not for the management of postoperative biliary complications.

METHODS

We present a case where ICG fluorescence imaging was used to identify a cut surface bile leak after pediatric split liver transplantation.

RESULTS

A 5-year-old girl with methylmalonic acidemia underwent a left lobe split liver transplantation. A single Roux-en-Y choledochojejunostomy was performed. Nine days after transplant, bile was noted in the surgical drain. Imaging confirmed the patency of the hepatic artery and the absence of intraabdominal collection. A hepatobiliary iminodiacetic acid scan showed the majority of radiotracer was excreted through the surgical drain. The patient was explored surgically: 4.5× loupe magnification did not allow for the localization of the leak. ICG was administered intravenously, after which a cut surface bile leak could be identified and repaired. There was no recurrence of bile leak after repair. Eighteen months after transplant, the patient is alive and well and has not suffered from any additional biliary complications.

CONCLUSION

Indocyanine green constitutes an additional tool in the arsenal of measures available to facilitate the intraoperative detection and management of bile leaks occurring after pediatric technical variant graft transplant.

Imaging Features of Main Posthepatectomy Complications: A Radiologist’s Challenge

In the recent years, the number of liver resections has seen an impressive growth. Usually, hepatic resections remain the treatment of various liver diseases, such as malignant tumors, benign tumors, hydatid disease, and abscesses. Despite technical advancements and tremendous experience in the field of liver resection of specialized centers, there are moderately high rates of postoperative morbidity and mortality, especially in high-risk and older patient populations. Although ultrasonography is usually the first-line imaging examination for postoperative complications, Computed Tomography (CT) is the imaging tool of choice in emergency settings due to its capability to assess the whole body in a few seconds and detect all possible complications. Magnetic resonance cholangiopancreatography (MRCP) is the imaging modality of choice for delineating early postoperative bile duct injuries and ischemic cholangitis that may arise in the late postoperative phase. Moreover, both MDCT and MRCP can precisely detect tumor recurrence. Consequently, radiologists should have knowledge of these surgical procedures for better comprehension of postoperative changes and recognition of the radiological features of various postoperative complications.

Magnetic Resonance Imaging of Liver Transplant

MR imaging increasingly has been adopted for follow-up imaging post-liver transplantation and for diagnosis of its complications. These include vascular and biliary complications as well as post-transplant malignancies. Interpretation of postoperative MR imaging should take into account the surgical technique and expected post-transplant changes. Contrast-enhanced MR imaging has high sensitivity for identification of vascular complications. MR cholangiopancreatography on the other hand is the most accurate noninvasive method for evaluation of biliary complications.

Gadoxetic acid magnetic-enhanced resonance imaging in the diagnosis of cholangiocarcinoma

The use of liver magnetic resonance imaging is increasing thanks to its multiparametric sequences that allow a better tissue characterization, and the use of hepatobiliary contrast agents. This review aims to evaluate gadoxetic acid enhanced magnetic resonance imaging in the diagnosis and staging of cholangiocarcinoma and its different clinical and radiological classifications proposed in the literature. We also analyze the epidemiology, risk factors in correlation with clinical findings and laboratory data.

Treatment strategy for isolated bile leakage after hepatectomy: Literature review

Isolated bile leakage (IBL) after hepatectomy is intractable, and various treatment methods for it have been reported. This review aimed to clarify the treatment strategy for IBL by summarizing studies on IBL after hepatectomy without extrahepatic bile duct resection. Thirty-three cases of IBL were reported. The incidence of IBL is very low, accounting for 0.1%-1% of all hepatectomy cases. The risk factors for IBL are unclear; however, several reports mention that biliary anomaly is associated with a high risk of IBL, with preoperative and intraoperative confirmation of biliary tree anatomy being the most important preventive strategy. Treatment methods for IBL include liver resection, bilioenteric anastomosis, endoscopic treatment, bile duct ablation, percutaneous transhepatic portal vein embolization (PTPE), transcatheter arterial embolization, and use of fibrin glue. The therapeutic methods should be chosen depending on remnant liver function, amount of bile leakage, and the liver volume causing the bile leakage. When there is bile leakage from less than one segment, non-surgical treatment is recommended, whereas when there is bile leakage from one or more segments, surgical treatment can be recommended. Nevertheless, recently, non-surgical treatment such as PTPE, PTPE with bile duct ablation, and endoscopic methods have been considered as effective treatment approaches.

Complications of hepatic echinococcosis: multimodality imaging approach

Hydatid disease is a worldwide zoonosis endemic in many countries. Liver echinococcosis accounts for 60-75% of cases and may be responsible for a wide spectrum of complications in about one third of patients. Some of these complications are potentially life-threatening and require prompt diagnosis and urgent intervention. In this article, we present our experience with common and uncommon complications of hepatic hydatid cysts which include rupture, bacterial superinfection, and mass effect-related complications. Specifically, the aim of this review is to provide key imaging features and diagnostic clues to guide the imaging diagnosis using a multimodality imaging approach, including ultrasound (US), computed tomography (CT), magnetic resonance (MR), and endoscopic retrograde cholangiopancreatography (ERCP).

Gd-EOB-DTP-enhanced MRC in the preoperative percutaneous management of intra and extrahepatic biliary leakages: does it matter?

Postoperative bile leakage is a common complication of abdominal surgical procedures and a precise localization of is important to choose the best management. Many techniques are available to correctly identify bile leaks, including ultrasound (US), computed tomography (CT) or magnetic resonance imaging (MRI), being the latter the best to clearly depict "active" bile leakages. This paper presents the state of the art algorithm in the detection of biliary leakages in order to plan a percutaneous biliary drainage focusing on widely available and safe contrast agent, the Gb-EOB-DPA. We consider its pharmacokinetic properties and impact in biliary imaging explain current debates to optimize image quality. We report common sites of leakage after surgery with special considerations in cirrhotic liver to show what interventional radiologists should look to easily detect bile leaks.

Misleading findings of liver-specific MR contrast agent for radiological diagnosis of cysto-biliary communication in hydatid cysts

OBJECTIVE

To investigate the effectiveness of gadoxetic acid-enhanced magnetic resonance cholangiopancreatography (CE-MRCP) and T2-weighted half-Fourier acquisition single-shot turbo spin-echo (T2W HASTE) sequences for diagnosis of cysto-biliary communication in hydatid cysts compared to surgical results.

METHODS

Preoperative abdominal magnetic resonance imaging examinations of patients who underwent surgery for hepatic hydatid cysts were reviewed by two radiologists retrospectively. A total of 45 patients with hydatid cysts were included. Of 45, 27 also had CE-MRCPs. T2W HASTE sequences and CE-MRCPs were investigated separately for cysto-biliary communication. The relationship between radiological and surgical results was analyzed. The interobserver agreement was evaluated.

RESULTS

Of 45 hydatid cysts, there were surgically proven 21 cysts without biliary communications and 24 cysts with biliary communications. All cysts with biliary communications were shown on T2W HASTE sequences. There was no leakage of gadoxetic acid into these cysts (n = 24). Sensitivity, specificity, negative predictive value, positive predictive value (PPV), and accuracy of diagnosis of cyst with biliary communication on T2W HASTE sequences was 100%, 63.64%, 100%, 66.67%, and 78.95%, respectively. Specificity (77.78%), PPV (87.50%), and accuracy (91.30%) were increased in ≥ 10 cm cysts. There was almost perfect interobserver agreement (K = 0.81-1.00).

CONCLUSION

Leakage of gadoxetic acid inside the cyst indicates biliary communication. However, the lack of leakage does not rule out cysto-biliary communication. When biliary communication is clearly shown on T2W HASTE sequences, it should be reported as cysto-biliary communication even if there is no leakage of gadoxetic acid into the cyst on CE-MRCP.

Early cross-sectional imaging following open and laparoscopic cholecystectomy: a primer for radiologists

Abstract

Performed on either an elective or urgent basis, cholecystectomy currently represents the most common abdominal operation due to the widespread use of laparoscopy and the progressively expanded indications. Compared to traditional open surgery, laparoscopic cholecystectomy minimised the duration of hospitalisation and perioperative mortality. Albeit generally considered safe, cholecystectomy may result in adverse outcomes with non-negligible morbidity. Furthermore, the incidence of worrisome haemorrhages and biliary complications has not been influenced by the technique shift. Due to the growing medico-legal concerns and the vast number of cholecystectomies, radiologists are increasingly requested to investigate recently operated patients. Aiming to increase familiarity with post-cholecystectomy cross-sectional imaging, this paper provides a brief overview of indications and surgical techniques and illustrates the expected early postoperative imaging findings. Afterwards, most iatrogenic complications following open, converted, laparoscopic and laparo-endoscopic rendezvous cholecystectomy are reviewed with examples, including infections, haematoma and active bleeding, residual choledocholithiasis, pancreatitis, biliary obstruction and leakage. Multidetector computed tomography (CT) represents the “workhorse” modality to rapidly investigate the postoperative abdomen in order to provide a reliable basis for an appropriate choice between conservative, interventional or surgical treatment. Emphasis is placed on the role of early magnetic resonance cholangiopancreatography (MRCP) and additional gadoxetic acid-enhanced MRCP to provide a non-invasive anatomic and functional assessment of the operated biliary tract.

Teaching Points

• Having minimised perioperative mortality and hospital stay, laparoscopy has now become the first-line approach to performing cholecystectomy, even in patients with acute cholecystitis.

• Laparoscopic, laparo-endoscopic rendezvous, converted and open cholecystectomy remain associated with non-negligible morbidity, including surgical site infections, haemorrhage, residual lithiasis, pancreatitis, biliary obstruction and leakage.

• Contrast-enhanced multidetector computed tomography (CT) is increasingly requested early after cholecystectomy and represents the “workhorse” modality that rapidly provides a comprehensive assessment of the operated biliary tract and abdomen.

• Magnetic resonance cholangiopancreatography (MRCP) is the best modality to provide anatomic visualisation of the operated biliary tract and is indicated when biliary complications are suspected.

• Additional gadoxetic acid (Gd-EOB-DTPA)-enhanced MRCP non-invasively provides functional biliary assessment, in order to confirm and visualise bile leakage.

Detection and characterization of traumatic bile leaks using Gd-EOB-DTPA enhanced magnetic resonance cholangiography

Expanding bile leaks after blunt liver trauma require more aggressive treatment than contained bile leaks. In this retrospective study approved by institution review board, we analyzed if non-invasive contrast-enhanced magnetic resonance cholangiography (CEMRC) using hepatocyte-specific contrast agent (gadoxetic acid disodium) could detect and characterize traumatic bile leaks. Between March 2012 and December 2014, written informed consents from 22 included patients (17 men, 5 women) with a median age of 24.5 years (IQR 21.8, 36.0 years) were obtained. Biliary tree visualization and bile leak detection on CEMRC acquired at 10, 20, 30, 90 minutes time points were independently graded by three radiologists on a 5-point Likert scale. Intraclass Correlation (ICC) was computed as estimates of interrater reliability. Accuracy was measured by area under receiver operating characteristic curves (AUROC). Biliary tree visualization was the best on CEMRC at 90 minutes (score 4.30) with excellent inter-rater reliability (ICC = 0.930). Of 22 CEMRC, 15 had bile leak (8 expanding, 7 contained). The largest AUROC of bile leak detection by three radiologists were 0.824, 0.914, 0.929 respectively on CEMRC at 90 minutes with ICC of 0.816. In conclusion, bile leaks of blunt liver trauma can be accurately detected and characterized on CEMRC.

Peritoneal and pleural fluids may appear hyperintense on hepatobiliary phase using hepatobiliary MR contrast agents

AIM

To describe the effect of hepatobiliary-specific MR imaging contrast agent (HBCA) administration on the signal intensity of peritoneal and pleural fluid effusions on T1-weighted MR images.

MATERIALS AND METHODS

From October 2015 to May 2016 139 patients (mean 60±10 years old, 69 % males) with peritoneal or pleural effusions without biliary leakage who underwent HBCA-MRI (Gd-BOPTA or Gd-EOB-DTPA) at 1.5T and 3T were included from two centres. The fluid signal intensity was classified as hypo/iso/hyperintense before/after HBCA administration. The relative signal enhancement (RE) was calculated.

RESULTS

On hepatobiliary phase (HBP), peritoneal fluids appeared hyper/isointense in 88-100 % and pleural effusions in 100 % of the patients following Gd-BOPTA administration. All fluids remained hypointense following Gd-EOB-DTPA. The signal intensity of fluids increased with both HBCA but RE was significantly higher following Gd-BOPTA (p=0.002 to <0.001). RE was correlated with HBP acquisition time-point (r=0.42, p<0.001 and r=0.50, p=0.033 for peritoneal and pleural fluids).

CONCLUSION

The signal intensity of pleural and peritoneal fluids progressively increases following HBCA administration in the absence of biliary leakage. Due to its later hepatobiliary phase, this is more pronounced after Gd-BOPTA injection, leading to fluid hyperintensity that is not observed after Gd-EOB-DTPA injection.

KEY POINTS

• Fluids appear hyper/isointense on HBP in most patients after Gd-BOPTA injection. • Fluids remain hypointense on HBP after Gd-EOB-DTPA injection. • RE of fluids increases with time after liver-specific Gd injection. • RE of fluids is higher in patients with chronic liver disease.

Liver Masses: What Physicians Need to Know About Ordering and Interpreting Liver Imaging

PURPOSE OF REVIEW

This paper reviews diagnostic imaging techniques used to characterize liver masses and the imaging characteristics of the most common liver masses.

RECENT FINDINGS

The role of recently adopted ultrasound and magnetic resonance imaging contrast agents will be emphasized. Contrast-enhanced ultrasound is an inexpensive exam which can confirm benignity of certain liver masses without ionizing radiation. Magnetic resonance imaging using hepatocyte-specific gadolinium-based contrast agents can help confirm or narrow the differential diagnosis of liver masses.

Hepatobiliary phase MRI: impact on planning image-guided liver tumor ablations

PURPOSE

To assess the impact of hepatobiliary phase images obtained during intravenous gadoxetate disodium-enhanced liver MRI in the planning of image-guided liver tumor ablations.

METHODS

This institutional review board-approved retrospective study included 34 patients (21 men, 13 women, ages 25-80) who underwent 36 liver MRI examinations with gadoxetate disodium within 12 weeks prior to image-guided thermal ablation of 62 liver tumors during 36 procedures. Visibility of bile ducts, subdivided by branch order, on hepatobiliary phase images was compared to standard MRI sequence images by an attending abdominal radiologist and fellow. Interventional decision making (whether or not to ablate and technical plan) using hepatobiliary phase images was compared with standard MRI sequences by the ablationists. The technical success and adverse events of ablation procedures were noted.

RESULTS

Bile duct visibility was significantly increased by at least one branch order in 18/36 (50%) examinations (p < 0.0001). Interventional decisions were significantly impacted in 15 (41.7%) of 36 ablation procedures (p < 0.0001), including changes to the technical plan in six (16.7%) of these procedures (p = 0.005). Technical success was achieved for 60/62 (97%) of tumors. Mild (grade 1) adverse events occurred in 4/36 (11%) procedures; no biliary complications occurred.

CONCLUSIONS

Use of hepatobiliary phase images obtained during gadoxetate disodium-enhanced liver MRI impacted both when and how to perform image-guided liver tumor ablations in our practice.

Added value of gadoxetic acid-enhanced T1-weighted magnetic resonance cholangiography for the diagnosis of post-transplant biliary complications

OBJECTIVES

Biliary complications after liver transplantation (LT) are common. This study aimed to ascertain the value of gadoxetic acid-enhanced T1-weighted (T1w) magnetic resonance cholangiography (MRC) to evaluate anastomotic strictures (AS), non-anastomotic strictures (NAS) and biliary casts (BC).

METHODS

Sixty liver-transplanted patients with suspicion of biliary complications and T2w-MRCP and T1w-MRC followed by endoscopic retrograde cholangiopancreatography (ERCP) or percutaneous transhepatic cholangiography (PTC) were analysed. Two readers reviewed the MRCs and rated image quality (IQ) and likelihood for AS/NAS/BC on Likert scales. Sensitivity, specificity and predictive values were calculated, ROC curve analysis performed, and inter-reader variability assessed. The subjective added value of T1w-MRC was rated.

RESULTS

IQ was high for all sequences without significant differences (2.83-2.88). In 39 patients ERCP/PTC detected a complication. Sensitivity and specificity for AS were 64-96 using T2w-MRCP, increasing to 79-100 using all sequences. Use of all sequences increased the sensitivity of detecting NAS/BC from 72-92% to 88-100% and 67-89% to 72-94%, respectively. Kappa values were substantial (0.45-0.62). T1w-MRC was found to be helpful in 75-83.3%.

CONCLUSIONS

Combining T1w-MRC and T2w-MRCP increased sensitivity and specificity and diagnostic confidence in patients after LT with suspected biliary complications. T1w-MRC is a valuable tool for evaluating post-transplant biliary complications.

KEY POINTS

• T1w-MRC is a valuable tool for evaluating post-transplant biliary complications. • Adding T1w-MRC to T2w-MRC increases diagnostic confidence for detection of biliary complications. • A combination of T1w-MRC and T2w-MRCP leads to the best results.

Contrast-Enhanced Magnetic Resonance Cholangiography: Practical Tips and Clinical Indications for Biliary Disease Management

Since its introduction, MRCP has been improved over the years due to the introduction of several technical advances and innovations. It consists of a noninvasive method for biliary tree representation, based on heavily T2-weighted images. Conventionally, its protocol includes two-dimensional single-shot fast spin-echo images, acquired with thin sections or with multiple thick slabs. In recent years, three-dimensional T2-weighted fast-recovery fast spin-echo images have been added to the conventional protocol, increasing the possibility of biliary anatomy demonstration and leading to a significant benefit over conventional 2D imaging. A significant innovation has been reached with the introduction of hepatobiliary contrasts, represented by gadoxetic acid and gadobenate dimeglumine: they are excreted into the bile canaliculi, allowing the opacification of the biliary tree. Recently, 3D interpolated T1-weighted spoiled gradient echo images have been proposed for the evaluation of the biliary tree, obtaining images after hepatobiliary contrast agent administration. Thus, the acquisition of these excretory phases improves the diagnostic capability of conventional MRCP—based on T2 acquisitions. In this paper, technical features of contrast-enhanced magnetic resonance cholangiography are briefly discussed; main diagnostic tips of hepatobiliary phase are showed, emphasizing the benefit of enhanced cholangiography in comparison with conventional MRCP.

Diagnostic value of Gd-EOB-DTPA-enhanced MR cholangiography in non-invasive detection of postoperative bile leakage

OBJECTIVE

To assess the diagnostic value of dynamic T₁ weighted (T1w) gadolinium ethoxybenzyl diethylenetriamine penta-acetic acid (Gd-EOB-DTPA)-enhanced MR cholangiography (MRC) for the detection of active bile leaks.

METHODS

A total of 28 patients with suspected biliary leakage who underwent routine T₂ weighted (T2w) MRC and T1w GD-EOB-DTPA-enhanced MRC at our institution from February 2013 to June 2016 were included in this study. The image sets were retrospectively analyzed in consensus by three radiologists. T1w Gd-EOB-DTPA-enhanced MRC findings were correlated with clinical data, follow-up examinations and findings of invasive/surgical procedures. Patients with positive bile leak findings in Gd-EOB-DTPA-enhanced MRC were divided into hepatobiliary phase (HBP) (20-30 min) and delayed phase (DP) (60-390 min) group according to elapsed time between Gd-EOB-DTPA injection and initial bile leak findings in MRC images. These groups were compared in terms of laboratory test results (total bilirubin, liver enzymes) and the presence of bile duct dilatation in T2w MRC images.

RESULTS

In each patient, visualization of bile ducts was sufficient in the HBP. The accuracy, sensitivity and specificity of dynamic Gd-EOB-DTPA-enhanced T1w MRC in the detection of biliary leaks were 92.9%, 90.5% and 100%, respectively (p < 0.001). 19 of 28 patients had bile leak findings in T1w Gd-EOB-DTPA-enhanced MRC [HBP group: N = 7 (36.8%), DP group: N = 12 (63.2%)]. There was no statistically significant difference in terms of laboratory test results and the presence of bile duct dilatation between HBP and DP group (p > 0.05). Three patients, each of them in DP group, showed normal laboratory test results and bile duct diameters.

CONCLUSION

Dynamic T1w Gd-EOB-DTPA-enhanced MRC is a useful non-invasive diagnostic tool to detect bile leak. Advances in knowledge: Prolonged DP imaging may be required for bile leak detection even if visualization of biliary tree is sufficient in HBP and liver function tests, total bilirubin levels and bile duct diameters are normal.

Unusual Use of Gd-EOB-DTPA in MRCP in Order to Reveal the Source of Bile Leakage in a Patient with Neuroendocrine Tumor - Case Report

BACKGROUND

MRCP is the method of choice in diagnosing pathologies of the biliary system. One of them is bile fistulae. They are uncommon but tend to cause many diagnostic problems. The possible way to improve MRCP is using it with intravenous injection of hepatobiliary-specific contrast agents. As it is eliminated via the hepatobiliary system, it can be visualized in the bile ducts and may help to reveal disorders undetected by a standard MRCP.

CASE REPORT

We report a case of a 36-year-old woman with leakage in the biliary system which led to creation of a subcutaneous bile reservoir. By means of a regular MRCP protocol it was impossible to reveal any disorders of the biliary system and thus a decision to inject Gd-EOB-DTPA was taken. As a result, a fistula with its opening in the fundus of the gall bladder was revealed. Patient was qualified for treatment with somatostatin analogues in order to stop bile secretion.

CONCLUSIONS

The Gd-EOB-DTPA in combination with regular T2-weighted MRCP may be helpful in detecting anomalies of the biliary system. Although a high price of the procedure restricts its accessibility, such advantages as lower risk of complications, lower costs of hospitalization, and less traumatic nature make it a technique that may take precedence over ERCP in ambiguous cases.

Inversion of excreted intravenous contrast-fluid levels in the urinary bladder on computed tomography

Fluid-fluid levels occur on computed tomography due to differences in density between the 2 fluids. For example, intravenous (IV) contrast excreted into the urinary bladder layers posterior with gravity in the supine patient with normal, unopacified urine layering anterior, due to their differing densities. The rare presence of inverted fluid-contrast levels in the bladder calls attention to the existence of pathology such as microscopic hematuria, infectious debris, glycosuria, and purulent fluid. In such instances, the hypodense, nonopacified urine is the abnormality and is often only recognized due to the excreted IV contrast "floating" on top of it within the bladder. Here, we describe a case in which the development of inverted fluid-contrast levels in the urinary bladder on computed tomography during a patient's hospital stay heralded further investigation with urinalysis and urinary culture, with the known, worrisome causes able to be excluded.

Clinical application of modern ultrasound techniques after liver transplantation

Liver transplantation has been established as a first-line therapy for a number of indications. Conventional ultrasound and contrast-enhanced ultrasound (CEUS) are methods of choice during the postoperative period as a safe and fast tool to detect potential complications and to enable early intervention if necessary. CEUS increases diagnostic quality and is an appropriate procedure for the examination of vessels and possibly bile ducts. This article presents the state of the art of ultrasound application during the early period after liver transplantation. It addresses common vascular complications and describes the identification of postoperative abnormal findings using ultrasound and CEUS.

Imaging of the postoperative liver: review of normal appearances and common complications

Several benign and malignant liver diseases may require surgical treatment for cure, including anatomical resections based on the segmental anatomy of the liver, non-anatomical (wedge) resections, and surgical management of biliary cysts. The type of surgery depends not only on the location and the nature of the disease, but also on the expertise of the surgeon. Whereas ultrasonography is often the first-line imaging examination in case of suspected postoperative complication, multidetector computed tomography (MDCT) is of greater value for identifying normal findings after surgery, early postoperative pathologic fluid collections and vascular thromboses, and tumor recurrence in patients who have undergone hepatic surgery. Magnetic resonance cholangiopancreatography (MRCP) is the imaging modality of choice for depicting early postoperative bile duct injuries and ischemic cholangitis that may occur in the late postoperative phase. Both MDCT and MRCP can accurately depict tumor recurrence. Radiologists should become familiar with these surgical procedures to better understand postoperative changes, and with the normal imaging appearances of various postoperative complications to better differentiate between complications and normal findings.

Gadoxetic acid: pearls and pitfalls

Gadoxetic acid is a hepatocyte-specific magnetic resonance imaging contrast agent with the ability to detect and characterize focal liver lesions and provide structural and functional information about the hepatobiliary system. Knowledge of the pharmacokinetics of gadoxetic acid is paramount to understanding imaging protocol and lesion appearance and facilitates identification and avoidance of undesired effects with use of this intravenous contrast agent. This article reviews the utility of gadoxetic acid in liver and biliary imaging, with emphasis on the hepatobiliary phase.

Accumulation of Bile in the Gallbladder: Evaluation by means of Serial Dynamic Contrast-Enhanced Magnetic Resonance Cholangiography with Gadolinium Ethoxybenzyl Diethylenetriaminepentaacetic Acid

The aim of this study was to evaluate the process of biliary excretion of gadolinium ethoxybenzyl diethylenetriaminepentaacetic acid (Gd-EOB-DTPA) into the biliary tract and to assess the accumulation patterns in the gallbladder using MR cholangiography obtained with Gd-EOB-DTPA which is a liver-specific hepatobiliary contrast agent. Seventy-five patients underwent Gd-EOB-DTPA enhanced MR imaging. Serial multiphasic hepatobiliary phase imaging was qualitatively reviewed to evaluate the process of the biliary excretion of contrast agent into the bile duct and the gallbladder. The accumulation pattern of contrast agent into gallbladder was classified into two groups (group 1 = orthodromic type and group 2 = delayed type). Furthermore, the results in differences of the presence of T1 hyperintense bile or sludge of gallbladder, gall stones, wall thickening of gallbladder, chronic liver disease, and liver cirrhosis between two groups were compared. Forty-eight of 75 patients (64%) were included in group 1, and remaining 27 (36%) were in group 2. The frequency of the presence of T1 hyperintense bile or sludge of gallbladder was significantly higher in patients with group 2 than that in patients with group 1 (P = 0.041). MR cholangiography obtained with Gd-EOB-DTPA showed that there may be an association between the biliary accumulation pattern in the gallbladder and the pathological condition.

Biliary Anastomotic Leakage following Orthotopic Liver Transplant: The Use of Primovist (Gadoxetate Disodium) as an Intravenous MR Cholangiography Contrast Agent for Biliary Leakage

We present a case of postoperative biliary anastomotic leakage demonstrated on intravenous contrast-enhanced MRI performed with Primovist (Gadoxetate Disodium). Primovist has been widely used for its combined extracellular and hepatocyte-specific properties in the characterization of liver lesions. Another recognized, but less widely utilized property of Primovist is its ability to provide morphologic and functional assessment of the biliary system. In our case, Primovist-enhanced MR imaging demonstrated the presence and location of an active biliary leakage which was associated with free spillage into the peritoneum.

Detection and localization of bile duct leaks after cholecystectomy using Gd-EOB-DTPA-enhanced MR cholangiography: retrospective study of 16 patients

OBJECTIVE

To determine if gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance (MR) cholangiography can detect and localize bile duct leaks in postcholecystectomy patients.

MATERIAL AND METHODS

Four blinded independent radiologists performed a retrospective review of 16 consecutive patients who underwent MR cholangiography with intravenous Gd-EOB-DTPA for the evaluation of possible biliary leak. Image quality, ductal opacification, and presence and location of any bile leak were evaluated. An independent observer determined the criterion standard using a consensus of all chart, clinical, and imaging findings.

RESULTS

All 6 bile leaks confirmed at endoscopic retrograde cholangiopancreatography were diagnosed by all reviewers (sensitivity, 100%). Of the 10 patients with no leak, only one reader incorrectly diagnosed a bile leak in a single case (specificity, 98%). The accuracy for detection of the site of leak with Gd-EOB-DTPA-enhanced MR cholangiography was 80%.

CONCLUSION

Gadolinium-EOB-DTPA-enhanced MR can detect bile leaks with a high sensitivity and specificity.

Liver-specific agents for contrast-enhanced MRI: role in oncological imaging

Liver-specific magnetic resonance (MR) contrast agents are increasingly used in evaluation of the liver. They are effective in detection and morphological characterization of lesions, and can be useful for evaluation of biliary tree anatomy and liver function. The typical appearances and imaging pitfalls of various tumours at MR imaging performed with these agents can be understood by the interplay of pharmacokinetics of these contrast agents and transporter expression of the tumour. This review focuses on the applications of these agents in oncological imaging.

Diagnosis of postoperative bile leak and accurate localization of the site of leak by gadobenate dimeglumine-enhanced MR cholangiography in a child

Postoperative bile leaks are difficult to diagnose because signs and symptoms are nonspecific, and definitive diagnosis requires a drainage catheter to be placed that drains frank bile or fluid that turns out bile on laboratory analysis. Hepatobiliary scintigraphy, endoscopic retrograde cholangiopancreatography (ERCP) and percutaneous transhepatic cholangiography (PTC) have been traditionally used to diagnose bile leak. Scintigraphy has poor spatial resolution and cannot localize the site of leak, ERCP may not be possible with altered postoperative anatomy and PTC is invasive and difficult to perform in the absence of dilated ducts. Recently, contrast-enhanced MR cholangiography using hepatobiliary-specific contrast media has been shown to be a noninvasive, safe way to diagnose and localize the site of bile leak in adults. We report a case of postoperative bile leak after choledochal cyst resection in a child in whom diagnosis was confirmed and the site of leak was accurately localized using gadobenate-enhanced MR cholangiography. This case demonstrates the potential of hepatobiliary-specific contrast media to diagnose postoperative bile leak and accurately localize the site of the leak in children noninvasively.