B Van Beers

Assistance Publique – Hôpitaux de Paris, Lutetia Parisorum, Île-de-France, France

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Publications (225)534.03 Total impact

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    ABSTRACT: To assess the value of the liver and spleen viscoelastic parameters at multifrequency MR elastography to determine the degree of portal hypertension and presence of high-risk oesophageal varices in patients with cirrhosis. From January to September 2012, 36 consecutive patients with cirrhosis evaluated for transplantation were prospectively included. All patients underwent hepatic venous pressure gradient (HVPG) measurements and endoscopy to assess oesophageal varices. Multifrequency MR elastography was performed within the liver and spleen. The shear, storage and loss moduli were calculated and compared to the HVPG with Spearman coefficients and multiple regressions. Patients with and without severe portal hypertension and high-risk varices were compared with Mann-Whitney tests, logistic regression and ROC analysis. The liver storage and loss moduli and the spleen shear, storage and loss moduli correlated with the HVPG. At multiple regression, only the liver and the spleen loss modulus correlated with the HVPG (r = 0.44, p = 0.017, and r = 0.57, p = 0.002, respectively). The spleen loss modulus was the best parameter for identifying patients with severe portal hypertension (p = 0.019, AUROC = 0.81) or high-risk varices (p = 0.042, AUROC = 0.93). The spleen loss modulus appears to be the best parameter for identifying patients with severe portal hypertension or high-risk varices. 1. Noninvasive HVPG assessment can be performed with liver and spleen MR elastography 2. The spleen loss modulus enables the detection of high-risk oesophageal varices 3. The spleen loss modulus enables the detection of severe portal hypertension.
    European Radiology 03/2014; · 4.34 Impact Factor
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    ABSTRACT: Detection and characterization of focal lesions in the cirrhotic liver may pose a diagnostic dilemma. Several benign and malignant lesions may be found in a cirrhotic liver along with hepatocellular carcinoma (HCC), and may exhibit typical or atypical imaging features. In this pictorial essay, we illustrate computed tomography and magnetic resonance imaging findings of lesions such as simple bile duct cysts, hemangioma, focal nodular hyperplasia-like nodules, peribiliary cysts, intrahepatic cholangiocarcinoma, lymphoma, and metastases, all of which occur in cirrhotic livers with varying prevalences. Pseudolesions, such as perfusion anomalies, focal confluent fibrosis, and segmental hyperplasia, will also be discussed. Imaging characterization of non-HCC lesions in cirrhosis is important in formulating an accurate diagnosis and triaging the patient towards the most appropriate management.
    Diagnostic and interventional radiology (Ankara, Turkey) 02/2014; · 1.03 Impact Factor
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    ABSTRACT: To assess in a high-resolution model of thin liver rat slices which viscoelastic parameter at three-dimensional multifrequency MR elastography has the best diagnostic performance for quantifying liver fibrosis. The study was approved by the ethics committee for animal care of our institution. Eight normal rats and 42 rats with carbon tetrachloride induced liver fibrosis were used in the study. The rats were sacrificed, their livers were resected and three-dimensional MR elastography of 5±2 mm liver slices was performed at 7T with mechanical frequencies of 500, 600 and 700 Hz. The complex shear, storage and loss moduli, and the coefficient of the frequency power law were calculated. At histopathology, fibrosis and inflammation were assessed with METAVIR score, fibrosis was further quantified with morphometry. The diagnostic value of the viscoelastic parameters for assessing fibrosis severity was evaluated with simple and multiple linear regressions, receiver operating characteristic analysis and Obuchowski measures. At simple regression, the shear, storage and loss moduli were associated with the severity of fibrosis. At multiple regression, the storage modulus at 600 Hz was the only parameter associated with fibrosis severity (r = 0.86, p<0.0001). This parameter had an Obuchowski measure of 0.89+/-0.03. This measure was significantly larger than that of the loss modulus (0.78+/-0.04, p = 0.028), but not than that of the complex shear modulus (0.88+/-0.03, p = 0.84). Our high resolution, three-dimensional multifrequency MR elastography study of thin liver slices shows that the storage modulus is the viscoelastic parameter that has the best association with the severity of liver fibrosis. However, its diagnostic performance does not differ significantly from that of the complex shear modulus.
    PLoS ONE 01/2014; 9(4):e94679. · 3.73 Impact Factor
  • Bernard E Van Beers
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    ABSTRACT: Summary By showing that intravoxel incoherent motion parameters at diffusion-weighted magnetic resonance (MR) imaging may be indicators of the microcirculatory changes in patients with nonalcoholic steatohepatitis and fatty liver disease, Joo et al have taken a step forward in the validation of quantitative MR imaging parameters as biomarkers of nonalcoholic steatohepatitis and fatty liver disease. Further steps, including standardization, validation, and multiparametric imaging, must be taken before these parameters can be used as biomarkers in clinical practice.
    Radiology 01/2014; 270(1):1-2. · 6.34 Impact Factor
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    ABSTRACT: To determine the frequency and factors associated with the presence of T2 shine-through effect in hepatic hemangiomas on diffusion-weighted (DW) magnetic resonance (MR) sequences. This retrospective study was approved by institutional review board with waiver of informed consent. One hundred forty-nine consecutive patients with 388 hepatic hemangiomas who underwent a liver MR between January 2010 and November 2011 were included. MR analysis evaluated the lesion characteristics (signal intensities and enhancement patterns (classical, rapidly filling, delayed filling)), the presence of T2 shine-through effect on DW sequences (b values of 0, 150, and 600s/mm(2)), and apparent diffusion coefficient (ADC) values. Multivariate analysis was performed to study the factors associated with the T2 shine-through effect. T2 shine-through effect was observed in 204/388 (52.6%) of hepatic hemangiomas and in 100 (67.1%) patients. Mean ADC value of hemangiomas with T2 shine-through effect was significantly lower than hemangiomas without (2.0±0.48 vs 2.38±0.45, P<.0001). On multivariate analysis, high signal intensity on fat-suppressed T2-weighted fast spin-echo images, hemangiomas with classical or delayed enhancement, and the ADC of the liver were the only significant factors associated with T2 shine-through effect. T2 shine-through effect is commonly observed in hepatic hemangiomas and is related to hemangiomas characteristics. Radiologists should be aware of this phenomenon which could lead to misdiagnosis. Its presence should not question the diagnosis of hemangiomas when typical MR findings are found.
    European journal of radiology 12/2013; · 2.65 Impact Factor
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    ABSTRACT: Magnetic resonance (MR) techniques allow noninvasive fat quantification. We aimed to investigate the accuracy of MR imaging (MRI), MR spectroscopy (MRS) and histological techniques to detect early-onset liver steatosis in three rat phenotypes assigned to an experimental glucolipotoxic model or a control group. This study was approved by the institutional committee for the protection of animals. Thirty-two rats (13 young Wistar, 6 old Wistar and 13 diabetic Goto-Kakizaki rats) fed a standard diet were assigned to a 72h intravenous infusion of glucose and Intralipid fat emulsion or a saline infusion. Plasma insulin levels were measured. Steatosis was quantified in ex vivo livers with gradient-recalled multi-echo MRI, MRS and histology as fat fractions (FF). A significant correlation was found between multi-echo MRI-FF and MRS-FF (r=0.81, p<0.01) and a weaker correlation was found between histology and MRS-FF (r=0.60, p<0.01). MRS and MRI accurately distinguished young Wistar and Goto-Kakizaki rats receiving the glucose+Intralipid infusion from those receiving the saline control whereas histology did not. Significant correlations were found between MRI or MRS and insulin plasma level (r=0.63, p<0.01; r=0.57, p<0.01), and between MRI or MRS and C-peptide concentration (r=0.54, p<0.01; r=0.44, p<0.02). Multi-echo MRI and MRS may be more sensitive to measure early-onset liver steatosis than histology in an experimental glucolipotoxic rat model.
    Metabolism: clinical and experimental 09/2013; · 3.10 Impact Factor
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    ABSTRACT: Liver perfusion imaging is a quantitative functional investigation. Liver perfusion imaging is complicated because of the liver's dual vascular supply, artefacts due to respiratory movements and the fenestrated sinusoidal capillaries which allow the contrast medium to diffuse out. Liver perfusion can be examined by ultrasound, CT or MRI: each technique has its limitations and specific features. The major indications in hepatology are oncology (detection, characterization and tumor response) and non-invasive investigation of patients with chronic liver disease. Work is needed to standardize acquisition and modeling methods to allow wider use of results and more widespread use of the technique.
    Diagnostic and interventional imaging. 07/2013;
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    ABSTRACT: In MR elastography (MRE), periodic tissue motion is phase encoded using motion-encoding gradients synchronized to an externally applied periodic mechanical excitation. Conventional methods result in extended scan time for quality phase images, thus limiting the broad application of MRE in the clinic. For practical scan times, researchers have been relying on one-dimensional or two-dimensional motion-encoding, low-phase sampling and a limited number of slices, and artifact-prone, single-shot, echo planar imaging (EPI) readout. Here, we introduce a rapid multislice pulse sequence capable of three-dimensional motion encoding that is also suitable for simultaneously encoding motion with multiple frequency components. This sequence is based on a gradient-recalled echo (GRE) sequence and exploits the principles of fractional encoding. This GRE MRE pulse sequence was validated as capable of acquiring full three-dimensional motion encoding of isotropic voxels in a large volume within less than a minute. This sequence is suitable for monofrequency and multifrequency MRE experiments. In homogeneous paraffin phantoms, the eXpresso sequence yielded similar storage modulus values as those obtained with conventional methods, although with markedly reduced variances (7.11 ± 0.26 kPa for GRE MRE versus 7.16 ± 1.33 kPa for the conventional spin-echo EPI sequence). The GRE MRE sequence obtained better phase-to-noise ratios than the equivalent spin-echo EPI sequence (matched for identical acquisition time) in both paraffin phantoms and in vivo data in the liver (59.62 ± 11.89 versus 27.86 ± 3.81, 61.49 ± 14.16 versus 24.78 ± 2.48 and 58.23 ± 10.39 versus 23.48 ± 2.91 in the X, Y and Z components, respectively, in the case of liver experiments). Phase-to-noise ratios were similar between GRE MRE used in monofrequency or multifrequency experiments (75.39 ± 14.93 versus 86.13 ± 18.25 at 28 Hz, 71.52 ± 24.74 versus 86.96 ± 30.53 at 56 Hz and 95.60 ± 36.96 versus 61.35 ± 26.25 at 84Hz, respectively). Copyright © 2013 John Wiley & Sons, Ltd.
    NMR in Biomedicine 05/2013; · 3.45 Impact Factor
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    ABSTRACT: OBJECTIVE: The objective of this study was to compare the value of the apparent diffusion coefficient (ADC) determined with 3 b values and the intravoxel incoherent motion (IVIM)-derived parameters in the determination of malignancy and characterization of hepatic tumor type. MATERIALS AND METHODS: Seventy-six patients with 86 solid hepatic lesions, including 8 hemangiomas, 20 lesions of focal nodular hyperplasia, 9 adenomas, 30 hepatocellular carcinomas, 13 metastases, and 6 cholangiocarcinomas, were assessed in this prospective study. Diffusion-weighted images were acquired with 11 b values to measure the ADCs (with b = 0, 150, and 500 s/mm) and the IVIM-derived parameters, namely, the pure diffusion coefficient and the perfusion-related diffusion fraction and coefficient. The diffusion parameters were compared between benign and malignant tumors and between tumor types, and their diagnostic value in identifying tumor malignancy was assessed. RESULTS: The apparent and pure diffusion coefficients were significantly higher in benign than in malignant tumors (benign: 2.32 [0.87] × 10 mm/s and 1.42 [0.37] × 10 mm/s vs malignant: 1.64 [0.51] × 10 mm/s and 1.14 [0.28] × 10 mm/s, respectively; P < 0.0001 and P = 0.0005), whereas the perfusion-related diffusion parameters did not differ significantly between the 2 groups. The apparent and pure diffusion coefficients provided similar accuracy in assessing tumor malignancy (areas under the receiver operating characteristic curve of 0.770 and 0.723, respectively). In the multigroup analysis, the ADC was found to be significantly higher in hemangiomas than in hepatocellular carcinomas, metastases, and cholangiocarcinomas. In the same manner, it was higher in lesions of focal nodular hyperplasia than in metastases and cholangiocarcinomas. However, the pure diffusion coefficient was significantly higher only in hemangiomas versus hepatocellular and cholangiocellular carcinomas. CONCLUSIONS: Compared with the ADC, the diffusion parameters derived from the IVIM model did not improve the determination of malignancy and characterization of hepatic tumor type.
    Investigative radiology 05/2013; · 4.85 Impact Factor
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    ABSTRACT: OBJECTIVES: To compare diffusion-weighted (DW) and T2-weighted MR imaging in detecting colorectal liver metastases in a rat model, using histological examination as a reference method. METHODS: Eighteen rats had four liver injections of colon cancer cells. MR examinations at 7 T included FSE-T2-weighted imaging and SE-DW MR imaging (b = 0, 20 and 150 s/mm2) and were analysed by two independent readers. Histological examination was performed on 0.4-mm slices. McNemar's test was used to compare the sensitivities and the Wilcoxon matched pairs test to compare the average number of false-positives per rat. RESULTS: One hundred and sixty-six liver metastases were identified on histological examination. The sensitivity in detecting liver metastases was significantly higher on DW MR than on T2-weighted images (99/166 (60 %) (reader 1) and 92/166 (55 %) (reader 2) versus 77/166 (46 %), P ≤ 0.001), without an increase in false-positives per rat (P = 0.773/P = 0.850). After stratification according to metastasis diameter, DW MR imaging had a significantly higher sensitivity than T2-weighted imaging only for metastases with a diameter (0.6-1.2 mm) similar to that of the spatial resolution of MR imaging in the current study. CONCLUSIONS: This MR study with histological correlations shows the higher sensitivity of DW relative to T2-weighted imaging at 7 T for detecting liver metastases, especially small ones. KEY POINTS: • Diffusion weighted (DW) sequences are increasingly used in magnetic resonance imaging (MRI). • DW has higher sensitivity for liver metastases than T2-weighted imaging at 7 T. • This increase in sensitivity is especially marked for small liver metastasis detection. • This higher sensitivity is confirmed in an animal model with histological correlation. • DW imaging has the potential for earlier diagnosis of small liver metastases.
    European Radiology 03/2013; · 4.34 Impact Factor
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    ABSTRACT: L’imagerie de perfusion hépatique est une modalité d’étude quantitative et fonctionnelle. La difficulté, dans le cas du foie, vient de son double apport vasculaire, des artéfacts liés aux mouvements respiratoires et aux capillaires sinusoïdes fenêtrés laissant diffuser le traceur. On peut étudier la perfusion hépatique en échographie, scanner ou IRM et chaque technique présente limites et spécificités. Les grandes indications en hépatologie sont l’oncologie (détection, caractérisation et réponse tumorale) et l’exploration non invasive des maladies hépatiques chroniques. Des efforts de standardisation sont nécessaires concernant les modalités d’acquisition et la modélisation pour permettre une diffusion des résultats et une utilisation plus large.
    Journal de Radiologie Diagnostique et Interventionnelle. 01/2013;
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    ABSTRACT: 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/mm(2) 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) mm(2)/s versus 1.18 ± 0.09 × 10(-3) mm(2)/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.
    European Radiology 09/2012; · 4.34 Impact Factor
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    ABSTRACT: To determine if diffusion-weighted (DW) magnetic resonance (MR) imaging with measurements of the apparent diffusion coefficient (ADC), pure diffusion coefficient, perfusion-related diffusion coefficient, and perfusion fraction can be used to differentiate between viable tumor and fibrous and necrotic regions within malignant liver tumors. The prospective study was approved by the institutional review board, and informed consent was obtained from all patients. Forty-eight patients with 51 malignant tumors were assessed. MR images of the liver were obtained by using DW imaging with 11 b factors (0-500 sec/mm(2)) and gadolinium-enhanced three-dimensional gradient-echo T1-weighted imaging. Tumors were segmented into viable tumor and fibrous and necrotic regions according to the enhancement pattern after injection of a nonspecific gadolinium chelate and, in surgically removed lesions, results of histopathologic correlation. The ADC, pure diffusion coefficient, perfusion-related diffusion coefficient, and perfusion fraction were calculated, and values were compared between viable tumor and fibrous and necrotic regions with the Kruskal-Wallis test followed by the Dunn multiple comparison test. The pure diffusion coefficient differed significantly between regions of viable tumor tissue and fibrosis (1.16 × 10(-3) mm(2)/sec ± 0.29 and 1.48 × 10(-3) mm(2)/sec ± 0.31, respectively; P = .016) and between regions of viable tumor tissue and necrosis (1.70 × 10(-3) mm(2)/sec ± 0.49, P = .002). There was a significantly lower perfusion fraction in necrotic regions (14% ± 6) than in viable tumor regions (21% ± 8, P = .005), but the perfusion fraction of the fibrous regions (21% ± 7) did not differ significantly from that of the other two regions. ADCs and perfusion-related diffusion coefficients did not differ significantly among the three regions. Results of this study show that viable tumor regions in malignant liver tumors can be differentiated from fibrous and necrotic regions with use of the pure diffusion coefficient but not with the other diffusion parameters.
    Radiology 06/2012; 264(2):464-72. · 6.34 Impact Factor
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    ABSTRACT: To investigate the potential value of magnetic resonance (MR) elastography and diffusion-weighted (DW) MR imaging in the detection of microstructural changes of murine colon tumors during growth and antivascular treatment. The study was approved by the regional ethics committee for animal care. Sixty Balb-C mice, bearing ectopic and orthotopic colon tumors, were monitored for 3 weeks with high-resolution T2-weighted MR imaging, three-dimensional steady-state MR elastography, and DW MR imaging at 7 T. The same imaging protocol was performed 24 hours after injection of combretastatin A4 phosphate (CA4P) in 12 mice. The absolute value of the complex shear modulus (|G*|) and the apparent diffusion coefficient (ADC) were measured in the viable zones of tumors and compared with microvessel density (MVD), cellularity, and micronecrosis by using the Pearson correlation coefficient. During tumor growth, |G*| increase was correlated with MVD (r = 0.70 [P = .08] and r = 0.78 [P = .002], for both the ectopic and orthotopic models, respectively). Moreover, the ectopic tumors displayed decreased ADC, which correlated with increased cellularity (r = 0.77, P = .04), whereas no changes in ADC and cellularity were observed in orthotopic tumors. After CA4P administration, |G*| decreased in the ectopic model (P < .0001), similar to the MVD evolution (P = .03), whereas no significant changes in |G*| (P = .7) and MVD (P = .6) were observed in the orthotopic model. ADC increased in both models (P = .047 and P = .01 for the ectopic and the orthotopic models, respectively) in relation to increased micronecrosis. Imaging of mechanical properties and diffusivity provide complementary information during tumor growth and regression that are respectively linked to vascularity and tumor cell alterations, including cellularity and micronecrosis.
    Radiology 06/2012; 264(2):436-44. · 6.34 Impact Factor
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    ABSTRACT: To assess the value of the viscoelastic parameters in the characterisation of liver tumours at MR elastography. Ninety-four patients with liver tumours >1 cm prospectively underwent MR elastography using 50-Hz mechanical waves and a full three-directional motion-sensitive sequence. The model-free viscoelastic parameters (the complex shear modulus and its real and imaginary parts, i.e. the storage and loss moduli) were calculated in 72 lesions after exclusion of cystic, treated or histopathologically undetermined tumours. We observed higher absolute shear modulus and loss modulus in malignant versus benign tumours (3.38 ± 0.26 versus 2.41 ± 0.15 kPa, P < 0.01 and 2.25 ± 0.26 versus 1.05 ± 0.13 kPa, P < 0.001, respectively). Moreover, the loss modulus of hepatocellular carcinomas was significantly higher than in benign hepatocellular tumours. The storage modulus did not differ significantly between malignant and benign tumours. The area under the receiver-operating characteristic curve of loss modulus was significantly larger than that of the absolute shear modulus and storage modulus when comparing malignant and benign lesions. The increased loss modulus is a better discriminator between benign and malignant tumours than the increased storage modulus or absolute value of the shear modulus. KEY POINTS : • Magnetic Resonance elastography is a new method of assessing the liver. • Increased loss modulus is an indicator of malignancy in hepatic tumours. • Loss modulus is a better discriminator than absolute shear modulus values. • The viscoelastic properties of lesions offer promise for characterising liver tumours.
    European Radiology 05/2012; 22(10):2169-77. · 4.34 Impact Factor
  • Bernard E Van Beers, Catherine M Pastor, Hero K Hussain
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    ABSTRACT: Gadolinium ethoxybenzyl dimeglumine (Gd-EOB-DTPA, Primovist in Europe and Eovist in the USA) is a liver-specific magnetic resonance imaging contrast agent that has up to 50% hepatobiliary excretion in the normal liver. After intravenous injection, Gd-EOB-DTPA distributes into the vascular and extravascular spaces during the arterial, portal venous and late dynamic phases, and progressively into the hepatocytes and bile ducts during the hepatobiliary phase. The hepatocyte uptake of Gd-EOB-DTPA mainly occurs via the organic anion transporter polypeptides OATP1B1 and B3 located at the sinusoidal membrane and biliary excretion via the multidrug resistance-associated proteins MRP2 at the canalicular membrane. Because of these characteristics, Gd-EOB-DTPA behaves similarly to non-specific gadolinium chelates during the dynamic phases, and adds substantial information during the hepatobiliary phase, improving the detection and characterization of focal liver lesions and diffuse liver disease. This information is particularly relevant for the detection of metastases, and for the detection and characterization of nodular lesions in liver cirrhosis, including early hepatocellular carcinomas. Finally, GD-EOB-DTPA-enhanced magnetic resonance imaging may provide quantitative assessment regarding liver perfusion and hepatocyte function in diffuse liver diseases. The full potential of GD-EOB-DTPA-enhanced magnetic resonance imaging has to be established further. It is already clear that GD-EOB-DTPA-enhanced magnetic resonance imaging provides anatomic and functional information in the setting of focal and diffuse liver disease that is unattainable with magnetic resonance imaging enhanced with non-specific contrast agents.
    Journal of Hepatology 04/2012; 57(2):421-9. · 9.86 Impact Factor
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    ABSTRACT: Magnetic resonance imaging (MRI) can be made sensitive to diffusion of water molecules in biological tissues: this phenomenon can be quantitated to provide a biomarker, the apparent diffusion coefficient (ADC). Over the past decade, evidence has accumulated from numerous clinical and animal studies that ADC is abnormal in tumours; that elevated ADC reflects an elevated non-cellular fraction; and that acute increases in ADC following therapy can indicate that tumour cells have been killed. However there remain substantial challenges in ensuring robust and valid ADC measurements, particularly in multicentre studies in common sites of metastasis such as lung and liver. Moreover, there is uncertainty about how best to select the timing of observation post-therapy to avoid false-negatives, and how to minimise the confounding factors which could decouple drug-induced ADC increase from drug-induced cell kill. In this review we summarise the physical basis of the biomarker, the evidence that it reflects non-viable fraction, particularly in extracranial tumours, and suggest a roadmap for validation and qualification.
    European journal of cancer (Oxford, England: 1990) 03/2012; 48(4):425-31. · 4.12 Impact Factor
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    ABSTRACT: To analyze the signal intensity (SI) of benign hepatocellular lesions in high-b-value diffusion-weighted (DW) magnetic resonance (MR) images and to compare the apparent diffusion coefficient (ADC) values of focal nodular hyperplasias (FNHs) with those of hepatocellular adenomas (HCAs). This retrospective study was approved by institutional review board, with waiver of informed consent. Inclusion criteria were consecutive patients with diagnosed FNH or HCA who underwent MR imaging with a DW sequence of the liver at three b values, 0, 150, and 600 sec/mm2. The final study population included 67 patients (seven men, 60 women) with 90 hepatocellular lesions (54 FNHs, 36 HCAs). The mean ADC was compared between the lesions and the liver. Receiver operating characteristic analysis was performed to evaluate the diagnostic value of ADC for differentiating HCAs and FNHs. The mean ADC value of all FNHs and HCAs was significantly lower than that of the liver (P=.004). An ADC ratio below 15% was observed in 50 of 54 (93%) FNHs and in 29 of 36 (81%) HCAs. The mean ADC value of FNHs was significantly higher than that of HCAs (P<.001). The area under the receiver operating characteristic curve was 0.760. With a cutoff value of 1.37×10(-3) mm2/sec, the sensitivity and specificity for differentiating HCA from FNH were 70% and 76%, respectively. There was no significant difference in ADC values between HCA subtypes. The SI of most FNHs and HCAs (78 of 90, 87%) increased with increasing b values, whereas none showed a decrease in SI with increasing b values. When the DW MR criteria for benign and malignant liver tumors were applied, 44 of 90 (49%) lesions would have been considered malignant lesions, whereas the other lesions (46 of 90, 51%) would have been considered indeterminate. On DW MR images, benign hepatocellular lesions often show findings that suggest restricted diffusion.
    Radiology 12/2011; 262(2):511-9. · 6.34 Impact Factor
  • Bernard E Van Beers, Sabrina Doblas, Ralph Sinkus
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    ABSTRACT: Conventional MR imaging of the liver has a central role in the assessment of liver diseases. Diffusion-weighted MR imaging, MR elastography, and time-resolved dynamic contrast-enhanced MR imaging improve the anatomical information provided by conventional MR imaging and add quantitative functional information in diffuse and focal liver diseases. Particularly, accurate detection and characterization of liver fibrosis are feasible with quantitative MR elastography, detection of liver tumors is increased with diffusion-weighted MR imaging and time-resolved dynamic contrast-enhanced MR imaging, characterization of tumors can be improved with quantitative diffusion-weighted MR imaging and MR elastography. These methods also have the potential to provide adequate biomarkers for assessing the response to treatment. Currently, the main limitations of quantitative MR imaging are related to reproducibility, standardization, and/or limited clinical data. It is important to improve and standardize the quantitative MR methods and validate their role in large multicenter trials.
    Abdominal Imaging 05/2011; 37(2):155-63. · 1.91 Impact Factor
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    ABSTRACT: Undiagnosed occlusive disease of celiac trunk and/or superior mesenteric artery may lead to life-threatening complications after pancreatoduodenectomy. Retrospective analysis of a consecutive series of 171 patients scheduled for pancreatico- duodenectomy or total pancreatectomy. The prevalence of arterial occlusive disease was 5.9% (10 patients), including complete celiac artery occlusive disease in 2 patients (1.2%). Preoperative diagnosis was achieved in 90% of the patients by lateral-views of imaging studies. In arterial stenosis <50% (3 patients), abstention was always successful. In arterial stenosis >50%, successful treatment options included abstention (n=1), preoperative endovascular dilatation (n=1) or stenting (n=1), division of the median arcuate ligament with (n=1) or without (n=1) postoperative endovascular stenting, and aorto-hepatic bypass (2 patients). No early postoperative ischemic complications occurred. However, one patient died from late intestinal ischemia. Arterial occlusive disease is rare in patients undergoing pancreatico-duodenectomy but expose the patient to severe complications if undiagnosed. A tailored management according to the type of arterial stenosis, to patients' indication for surgery and to patients' arterial anatomy is indicated. Surgical and endovascular management may be successfully combined.
    Hepato-gastroenterology 01/2011; 58(109):1377-83. · 0.77 Impact Factor

Publication Stats

3k Citations
534.03 Total Impact Points

Institutions

  • 2010–2013
    • Assistance Publique – Hôpitaux de Paris
      • Department of Radiology
      Lutetia Parisorum, Île-de-France, France
  • 2008–2013
    • Paris Diderot University
      Lutetia Parisorum, Île-de-France, France
    • Université René Descartes - Paris 5
      Lutetia Parisorum, Île-de-France, France
  • 2012
    • University of Coimbra
      • Centro de Neurociências e Biologia Celular (CNC)
      Coimbra, Distrito de Coimbra, Portugal
  • 2011
    • Unité Inserm U1077
      Caen, Lower Normandy, France
  • 1988–2011
    • Catholic University of Louvain
      • Department of Radiology and Medical Imaging - RAIM
      Walloon Region, Belgium
  • 1992–2010
    • Cliniques Universitaires Saint-Luc
      • • Division of Abdominal Surgery and Transplantation
      • • Division of Radiology
      • • Department of Medical Imaging
      Brussels, BRU, Belgium
  • 1990–2001
    • University Hospital Brussels
      • Department of Radiology
      Brussels, BRU, Belgium
  • 1994
    • Johns Hopkins Medicine
      Baltimore, Maryland, United States
  • 1988–1994
    • Centre Hospitalier Universitaire Mont-Godinne
      Yvoir, Walloon Region, Belgium
  • 1988–1989
    • Université Paris-Sud 11
      Orsay, Île-de-France, France