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Leitao H.S.,University of Coimbra | Leitao H.S.,University Hospitals Paris Nord Val Of Seine | Doblas S.,University Hospitals Paris Nord Val Of Seine | D'Assignies G.,University Hospitals Paris Nord Val Of Seine | And 6 more authors.
European Radiology | Year: 2013

Purpose: Assess the effect of fat deposition on the MRI diffusion coefficients in lipid emulsion-based phantoms and patients with proven isolated liver steatosis. Materials and methods: Diffusion-weighted MRI with 11 b values from 0-500 s/mm2 was performed in phantoms (fat fractions 0-18 %) with and without fat suppression and in 19 patients with normal liver (n = 14) or isolated liver steatosis (n = 5) proven by histopathology. The apparent, pure and perfusion-related diffusion coefficients and the perfusion fraction were measured. Spearman correlation coefficient and Mann-Whitney U test were used for comparisons. Results: A strong correlation between the apparent and pure diffusion coefficients and fat fractions was seen in phantoms. The pure diffusion coefficient decreased significantly in patients with liver steatosis (0.96 ± 0.16 × 10-3 mm2/s versus 1.18 ± 0.09 × 10-3 mm2/s in normal liver, P = 0.005), whereas the decrease in apparent diffusion coefficient did not reach statistical significance (1.26 ± 0.25 × 10-3 mm 2/s versus 1.41 ± 0.14 × 10-3 mm 2/s in normal liver, P = 0.298). Conclusions: Fat deposition decreases the apparent and pure diffusion coefficients in lipid emulsion-based phantoms and patients with isolated liver steatosis proven by histopathology. Key Points: • Magnetic resonance imaging is increasingly used to quantify hepatic fibrosis. • Lipid phantoms show inverse correlations between diffusion coefficients and fat fractions. • The pure diffusion coefficient decreases in patients with isolated liver steatosis. • Steatosis may be a confounding factor when measuring the liver diffusion parameters. © 2012 European Society of Radiology.

Vilgrain V.,University Hospitals Paris Nord Val Of Seine | Vilgrain V.,University Paris Diderot | Van Beers B.E.,University Hospitals Paris Nord Val Of Seine | Van Beers B.E.,University Paris Diderot | And 3 more authors.
Journal of Hepatology | Year: 2016

The incidence of hepatocellular carcinomas (HCCs) has increased worldwide in line with an improved screening by high-resolution imaging of cirrhotic livers. Besides abdominal ultrasonography and computerised tomography, magnetic resonance imaging (MRI) is an important tool to detect HCCs. With commercialisation of MR hepatobiliary contrast agents that cross membrane transporters in hepatocytes or tumour cells, MRI adds new information to detect and characterise HCCs. When tumour cells lose organic anion transporting polypeptides (OATP1B1/B3) in cell membranes facing sinusoidal blood, tumours appear hypointense (decreased contrast agent concentrations) in comparison to surrounding normal or cirrhotic liver that retains OATP1B1/B3 expression. However, expression, regulation, and prognostic significance of transporter evolution along carcinogenesis are not completely known. Moreover, understanding signal intensities in focal lesions also relies on transport functions of cellular efflux transporters. This manuscript reviews all the publications that associate liver imaging with hepatobiliary contrast agents and expression of transporters. The regulation of transporters along carcinogenesis to anticipate the prognosis of focal lesions is also included. © 2015 European Association for the Study of the Liver.

Pupulim L.F.,University of Geneva | Vilgrain V.,University Hospitals Paris Nord Val Of Seine | Vilgrain V.,University Paris Diderot | Vilgrain V.,French Institute of Health and Medical Research | And 6 more authors.
Abdominal Imaging | Year: 2015

The liver normally produces a large amount of lymph. It is estimated that between 25% and 50% of the lymph received by the thoracic duct comes from the liver. In normal conditions, hepatic lymphatics are not depicted on cross-sectional imaging. They are divided in lymphatics of deep system (lymphatics following the hepatic veins and the portal tract) and those of superficial system (convex surface and inferior surface). A variety of diseases may affect hepatic lymphatics and in general they manifest as lymphedema, lymphatic mass, or cystic lesions. Abnormal distended lymphatics are especially seen in periportal spaces as linear hypoattenuations on CT or strong linear hyperintensities on heavily T2-weighted MR imaging. Lymphatic tumor spread as in lymphoma and lymphangitic carcinomatosis manifests as periportal masses and regional lymph node enlargement. Lymphatic disruption after trauma or surgery is depicted as perihepatic fluid collections of lymph (lymphocele). Lymphatic malformation such as lymphangioma is seen on imaging as cystic spaces of variable size. © 2015, Springer Science+Business Media New York.

Ronot M.,University Hospitals Paris Nord Val Of Seine | Ronot M.,University Paris Diderot | Ronot M.,French Institute of Health and Medical Research | Vilgrain V.,University Hospitals Paris Nord Val Of Seine | And 2 more authors.
Bailliere's Best Practice and Research in Clinical Gastroenterology | Year: 2014

Imaging plays a very important role in the diagnosis of HCC. Indeed, in high-risk patients a noninvasive diagnosis can only be obtained by imaging in presence of typical features. These features include arterial enhancement followed by washout during the portal venous and/or delayed phases on CT scan or MRI. This pattern is quite specific and has been endorsed by both Western and Asian diagnostic guidelines. However, its sensitivity is not very high, especially for small lesions. Therefore ancillary signs may be needed to increase the reliability of the diagnosis. Recent hepatobiliary MRI contrast agents seem to be interesting to improve characterization of small nodules in the cirrhotic liver. © 2014.

Bapst B.,University Hospitals Paris Nord Val Of Seine | Lagadec M.,University Hospitals Paris Nord Val Of Seine | Breguet R.,University of Geneva | Vilgrain V.,University Hospitals Paris Nord Val Of Seine | And 5 more authors.
CardioVascular and Interventional Radiology | Year: 2016

Cone beam computed tomography (CBCT) is an imaging modality that provides computed tomographic images using a rotational C-arm equipped with a flat panel detector as part of the Angiography suite. The aim of this technique is to provide additional information to conventional 2D imaging to improve the performance of interventional liver oncology procedures (intraarterial treatments such as chemoembolization or selective internal radiation therapy, and percutaneous tumor ablation). CBCT provides accurate tumor detection and targeting, periprocedural guidance, and post-procedural evaluation of treatment success. This technique can be performed during intraarterial or intravenous contrast agent administration with various acquisition protocols to highlight liver tumors, liver vessels, or the liver parenchyma. The purpose of this review is to present an extensive overview of published data on CBCT in interventional oncology of the liver, for both percutaneous ablation and intraarterial procedures. © 2015, Springer Science+Business Media New York and the Cardiovascular and Interventional Radiological Society of Europe (CIRSE).

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