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.

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SPIO-enhanced T2-weighted MR imaging was more accurate than nonenhanced T1-weighted and T2-weighted MR imaging and contrast-enhanced spiral CT for the detection of focal hepatic lesions. The combined analysis of nonenhanced and SPIO-enhanced images was more accurate in the characterization of focal hepatic lesions than was review of SPIO-enhanced images alone.

Screening of the liver for hepatic lesion detection and characterization is usually performed with either ultrasound or CT. However, both techniques are suboptimal for liver lesion characterization and magnetic resonance (MR) imaging has emerged as the preferred radiological investigation. In addition to unenhanced MR imaging techniques, contrast-enhanced MR imaging can demonstrate tissue-specific physiological information, thereby facilitating liver lesion characterization. Currently, the classes of contrast agents available for MR imaging of the liver include non-tissue-specific extracellular gadolinium chelates and tissue-specific hepatobiliary or reticuloendothelial agents. In this review, we describe the MR features of the more common focal hepatic lesions, as well as appropriate imaging protocols. A special emphasis is placed on the clinical use of non-specific and liver-specific contrast agents for differentiation of focal liver lesions. This may aid in the accurate diagnostic workup of patients in order to avoid invasive procedures, such as biopsy, for lesion characterization. A diagnostic strategy that considers the clinical situation is also presented.

Central venous port devices are indicated for patients, who need long-term intravenous therapy. Oncologic patients may require intermittent administration of chemotherapy, parenteral nutrition, infusions, or blood transfusions. A venous port system is composed of a port chamber attached to a central catheter, which is implanted into the central venous system. The subcutaneous location of the catheter chamber improves the patients’ quality of life and the infection rate is lower than in non-totally implantable central venous devices. However, proper implantation, use, and care of a port system are important to prevent short- and long-term complications. Most common early complications (< 30 days) include venous malpositioning of catheter and perforation with arterial injury, pneumothorax, hemothorax, thoracic duct injury, or even cardiac tamponade. Delayed complications include infection, catheter thrombosis, vessel thrombosis and stenosis, catheter fracture with extravasation, or fracture with migration or embolization of catheter material. Radiologic imaging has become highly relevant in intra-procedural assessment and postoperative follow-up, for detection of possible complications and to plan intervention, e.g., in case of catheter migration. This pictorial review presents the normal imaging appearance of central venous port systems and demonstrates imaging features of short- and long-term complications.

A wide variety of artifacts can be seen in clinical MR imaging. This review describes the most important and most prevalent of them, including magnetic susceptibility artifacts and motion artifacts, aliasing, chemical-shift, zipper, zebra, central point, and truncation artifacts. Although the elimination of some artifacts may require a service engineer, the radiologist and MR technologist have the responsibility to recognize MR imaging problems. This review shows the typical MR appearance of the described artifacts, explains their physical basis, and shows the way to solve them in daily practice.

ObjectivesTo develop a consensus and provide updated recommendations on liver MR imaging and the clinical use of liver-specific contrast agents.MethodsThe European Society of Gastrointestinal and Abdominal Radiology (ESGAR) formed a multinational European panel of experts, selected on the basis of a literature review and their leadership in the field of liver MR imaging. A modified Delphi process was adopted to draft a list of statements. Descriptive and Cronbach’s statistics were used to rate levels of agreement and internal reliability of the consensus.ResultsThree Delphi rounds were conducted and 76 statements composed on MR technique (n = 17), clinical application of liver-specific contrast agents in benign, focal liver lesions (n = 7), malignant liver lesions in non-cirrhotic (n = 9) and in cirrhotic patients (n = 18), diffuse and vascular liver diseases (n = 12), and bile ducts (n = 13). The overall mean score of agreement was 4.84 (SD ±0.17). Full consensus was reached in 22 % of all statements in all working groups, with no full consensus reached on diffuse and vascular diseases.ConclusionsThe consensus provided updated recommendations on the methodology, and clinical indications, of MRI with liver specific contrast agents in the study of liver diseases.Key points• Liver-specific contrast agents are recommended in MRI of the liver.• The hepatobiliary phase improves the detection and characterization of hepatocellular lesions.• Liver-specific contrast agents can improve the detection of HCC.

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