The Experts below are selected from a list of 324 Experts worldwide ranked by ideXlab platform
Jonathan Mamou - One of the best experts on this subject based on the ideXlab platform.
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Three-dimensional quantitative ultrasound to guide pathologists towards metastatic foci in Lymph Nodes
2012 Annual International Conference of the IEEE Engineering in Medicine and Biology Society, 2012Co-Authors: Jonathan Mamou, Alain Coron, Masaki Hata, Junji Machi, Eugene Yanagihara, Pascal Laugier, Emi Saegusa-beecroft, Michael L. Oelze, Tadashi Yamaguchi, Ernest J. FeleppaAbstract:The detection of metastases in freshly-excised Lymph Nodes from cancer patients during Lymphadenectomy is critically important for cancer staging, treatment, and optimal patient management. Currently, conventional histologic methods suffer a high rate of false-negative determinations because pathologists cannot evaluate each excised Lymph Nodes in its entirety. Therefore, Lymph Nodes are undersampled and and small but clinically relevant metastatic regions can be missed. In this study, quantitative ultrasound (QUS) methods using high-frequency transducers (i.e., >; 20 MHz) were developed and evaluated for their ability to detect and guide pathologists towards suspicious regions in Lymph Nodes. A custom laboratory scanning system was used to acquire radio-frequency (RF) data in 3D from excised Lymph Nodes using a 26-MHz center-frequency transducer. Overlapping 1-mm cylindrical regions-of-interest (ROIs) of the RF data were processed to yield 13 QUS estimates quantifying tissue microstructure and organization. These QUS methods were applied to more than 260 Nodes from more than 160 colorectal-, gastric-, and breast-cancer patients. Cancer-detection performance was assessed for individual estimates and linear combinations of estimates. ROC results demonstrated excellent classification. For colorectal- and gastric-cancer Nodes, the areas under the ROC curves (AUCs) were greater than 0.95. Slightly poorer results (AUC=0.85) were obtained for breast-cancer Nodes. Images based on QUS parameters also permitted localization of cancer foci in some micrometastatic cases.
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Three-dimensional quantitative high-frequency characterization of freshly-excised human Lymph Nodes
2011 IEEE International Ultrasonics Symposium, 2011Co-Authors: Jonathan Mamou, Alain Coron, Masaki Hata, Junji Machi, Eugene Yanagihara, Pascal Laugier, Emi Saegusa-beecroft, Michael L. Oelze, Tadashi Yamaguchi, Ernest J. FeleppaAbstract:High-frequency quantitative ultrasound (QUS) permits characterization of tissue microstructure using system-independent estimates. In this study, freshly-excised Lymph Nodes from cancer patients were evaluated using specifically designed three-dimensional (3D) QUS methods. The long-term objective was to develop 3D QUS methods for detecting metastases. Detection of metastases is critically important for cancer staging and treatment planning. A custom laboratory scanning system was used to acquire radio-frequency (RF) data in 3D from excised Lymph Nodes using a 26-MHz center-frequency transducer. Overlapping 1-mm cylindrical regions-of-interest (ROIs) of the RF data were processed to yield 13 QUS estimates associated with tissue microstructure. QUS estimates were obtained from more than 250 Nodes from more than 150 colorectal-, gastric-, and breast-cancer patients. Cancer-detection performance was assessed for individual estimates and linear combinations of estimates. ROC results demonstrated excellent classification. For colorectal- and gastric-cancer Nodes, the areas under the ROC curves (AUCs) were above 0.94. Slightly poorer results (AUC 0.87) were obtained for breast Nodes. Images based on QUS parameters also permitted localization of cancer foci in some micrometastatic cases. Therefore, these advanced 3D QUS methods potentially can be valuable for detecting small metastatic foci in dissected Lymph Nodes.
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three dimensional high frequency characterization of cancerous Lymph Nodes
Ultrasound in Medicine and Biology, 2010Co-Authors: Jonathan Mamou, Alain Coron, Masaki Hata, Junji Machi, Eugene Yanagihara, Pascal Laugier, E J FeleppaAbstract:High-frequency ultrasound (HFU) offers a means of investigating biological tissue at the microscopic level. High-frequency, three-dimensional (3D) quantitative-ultrasound (QUS) methods were developed to characterize freshly-dissected Lymph Nodes of cancer patients. 3D ultrasound data were acquired from Lymph Nodes using a 25.6-MHz center-frequency transducer. Each node was inked prior to tissue fixation to recover orientation after sectioning for 3D histological evaluation. Backscattered echo signals were processed using 3D cylindrical regions-of-interest to yield four QUS estimates associated with tissue microstructure (i.e., effective scatterer size, acoustic concentration, intercept, and slope). QUS estimates were computed following established methods using two scattering models. In this study, 46 Lymph Nodes acquired from 27 patients diagnosed with colon cancer were processed. Results revealed that fully-metastatic Nodes could be perfectly differentiated from cancer-free Nodes using slope or scatterer-size estimates. Specifically, results indicated that metastatic Nodes had an average effective scatterer size (i.e., 37.1 ± 1.7 um) significantly larger (p <0.05) than that in cancer-free Nodes (i.e., 26 ± 3.3 um). Therefore, the 3D QUS methods could provide a useful means of identifying small metastatic foci in dissected Lymph Nodes that might not be detectable using current standard pathology procedures.
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Three-dimensional high-frequency spectral and envelope quantification of excised human Lymph Nodes
2010 IEEE International Ultrasonics Symposium, 2010Co-Authors: Jonathan Mamou, Alain Coron, Masaki Hata, Junji Machi, Pascal Laugier, Emi Saegusa-beecroft, Michael L. Oelze, Eugene Yanagiharal, Ernest J. FeleppatAbstract:Quantitative imaging methods using high-frequency ultrasound (HFU, >;20 MHz) offer a means of characterizing biological tissue at the microscopic level. In this study, three-dimensional (3D) quantitative-ultrasound (QUS) methods were developed to detect metastases in freshly-dissected Lymph Nodes of cancer patients. 3D ultrasound radio-frequency data were acquired using a 26-MHz center-frequency transducer, and each node was inked prior to tissue fixation to recover orientation after sectioning for 3D histological evaluation. Backscattered echo signals were processed using 3D cylindrical regions-of-interest (ROIs) to yield eight QUS estimates associated with tissue microstructure. The first four QUS estimates (i.e., effective scatterer size, acoustic concentration, intercept, and slope) were estimated from a normalized backscattered spectrum, and the other four QUS estimates were obtained by parameterizing the envelope statistics of the ROIs using Nakagami and homodyned-K models. These QUS methods were applied to 145 Lymph Nodes from 95 colorectal and gastric cancer patients. The ability of these eight QUS estimates to classify Lymph Nodes and detect cancer was evaluated using ROC curves. An area under the ROC curve of 0.971 with specificity and sensitivity of 91% (using a leave-one-out procedure) were obtained by combining effective scatterer size and one envelope parameter based on the homodyned-K distribution. Therefore, these advanced 3D QUS methods potentially can be valuable for detecting small metastatic foci in dissected Lymph Nodes.
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Three-dimensional segmentation of high-frequency ultrasound echo signals from dissected Lymph Nodes
2008 IEEE Ultrasonics Symposium, 2008Co-Authors: Alain Coron, Jonathan Mamou, Masaki Hata, Junji Machi, Eugene Yanagihara, Pascal Laugier, Ernest J. FeleppaAbstract:Quantitative high-frequency ultrasound (QHFU) imaging methods are under investigation to evaluate their ability to detect small nodal metastases in Lymph Nodes freshly dissected from cancer patients. To apply these methods, a critical preprocessing step is 3D segmentation of the Lymph-node ultrasound echo-signal dataset. Segmenting the residual fat layer and the Lymph node is critical in order to avoid bias in the QHFU estimates (e.g., scatterer size and acoustic concentration) due to attenuation and to exclude estimates obtained from the fat regions. Segmentation also provides absolute measurements of Lymph-node dimensions that are necessary to match 3D ultrasound with 3D histology. In this study, a 3D region-based segmentation algorithm was developed and compared quantitatively using Dice's mutual-overlap criterion with 2D manual segmentation of 9 representative cross sections. The method was tested on 13 Lymph Nodes, and resulting Dice scores had mean values of 0.81 and 0.78 for Lymph node and fat segmentation, respectively.
Jeanphilippe Girard - One of the best experts on this subject based on the ideXlab platform.
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hevs Lymphatics and homeostatic immune cell trafficking in Lymph Nodes
Nature Reviews Immunology, 2012Co-Authors: Jeanphilippe Girard, Christine Moussion, Reinhold ForsterAbstract:The recirculation of Lymphocytes through Lymph Nodes and their encounter with dendritic cells is crucial for immunity. Here, the authors review the role of high endothelial venules, Lymphatics and Lymph node stroma in the trafficking of immune cells in Lymph Nodes during homeostasis.
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dendritic cells control Lymphocyte entry to Lymph Nodes through high endothelial venules
Nature, 2011Co-Authors: Jeanphilippe Girard, Christine MoussionAbstract:Christine Moussion and Jean-Philippe Girard report that dendritic cells in the immune system have an unexpected immune surveillance role in Lymphocyte recirculation during homeostasis. Lymphotoxin ligands derived from dendritic cells promote the growth of high endothelial venules — blood vessels specialized in Lymphocyte recruitment — which control the entry of naive Lymphocytes from the blood into Lymph Nodes. While patrolling the body in search of foreign antigens, naive Lymphocytes continuously circulate from the blood, through the Lymph Nodes, into the Lymphatic vessels and back to the blood1,2. This process, called Lymphocyte recirculation, provides the body with effective immune surveillance for foreign invaders and for alterations to the body’s own cells. However, the mechanisms that regulate Lymphocyte recirculation during homeostasis remain incompletely characterized. Here we show that dendritic cells (DCs), which are well known for their role in antigen presentation to T Lymphocytes3, control the entry of naive Lymphocytes to Lymph Nodes by modulating the phenotype of high endothelial venules (HEVs), which are blood vessels specialized in Lymphocyte recruitment2,4,5. We found that in vivo depletion of CD11c+ DCs in adult mice over a 1-week period induces a reduction in the size and cellularity of the peripheral and mucosal Lymph Nodes. In the absence of DCs, the mature adult HEV phenotype reverts to an immature neonatal phenotype, and HEV-mediated Lymphocyte recruitment to Lymph Nodes is inhibited. Co-culture experiments showed that the effect of DCs on HEV endothelial cells is direct and requires Lymphotoxin-β-receptor-dependent signalling. DCs express Lymphotoxin, and DC-derived Lymphotoxin is important for Lymphocyte homing to Lymph Nodes in vivo. Together, our results reveal a previously unsuspected role for DCs in the regulation of Lymphocyte recirculation during immune surveillance.
Armin Ernst - One of the best experts on this subject based on the ideXlab platform.
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endobronchial ultrasound guided transbronchial needle aspiration of Lymph Nodes in the radiologically normal mediastinum
European Respiratory Journal, 2006Co-Authors: Felix J F Herth, Ralf Eberhardt, Peter Vilmann, Armin Ernst, Hendrik Dienemann, Mark KrasnikAbstract:Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) can sample enlarged mediastinal Lymph Nodes in patients with nonsmall cell lung cancer (NSCLC). To date, EBUS-TBNA has only been used to sample Nodes visible on computed tomography (CT). The aim of the present study was to determine the accuracy of EBUS-TBNA in sampling Nodes ≤1 cm in diameter. NSCLC patients with CT scans showing no enlarged Lymph Nodes (no node >1 cm) in the mediastinum underwent EBUS-TBNA. Identifiable Lymph Nodes at locations 2r, 2l, 4r, 4l, 7, 10r, 10l, 11r and 11l were aspirated. All patients underwent subsequent surgical staging. Diagnoses based on aspiration results were compared with those based on surgical results. In 100 patients (mean age 58.9 yrs; 68 males), 119 Lymph Nodes ranging 5–10 mm in size were detected and sampled. Malignancy was detected in 19 patients but missed in two; all diagnoses were confirmed by surgical findings. The mean diameter of the punctured Lymph Nodes was 8.1 mm. The sensitivity of EBUS-TBNA for detecting malignancy was 92.3%, specificity was 100%, and the negative predictive value was 96.3%. No complications occurred. In conclusion, endobronchial ultrasound-guided transbronchial needle aspiration can accurately sample even small mediastinal Nodes, therefore avoiding unnecessary surgical exploration in one out of six patients who have no computed tomography evidence of mediastinal disease. Potentially operable patients with no signs of mediastinal involvement on computed tomography may benefit from pre-surgical endobronchial ultrasound-guided transbronchial needle aspiration and staging.
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real time endobronchial ultrasound guided transbronchial needle aspiration for sampling mediastinal Lymph Nodes
Thorax, 2006Co-Authors: Felix J F Herth, Ralf Eberhardt, Peter Vilmann, Mark Krasnik, Armin ErnstAbstract:Background: Transbronchial needle aspiration (TBNA) is an established method for sampling mediastinal Lymph Nodes to aid in diagnosing Lymphadenopathy and in staging lung cancers. Real-time endobronchial ultrasound (EBUS) guidance is a new method of TBNA that may increase the ability to sample these Nodes and hence to determine a diagnosis. A descriptive study was conducted to test this new method. Methods: Consecutive patients referred for TBNA of mediastinal Lymph Nodes were included in the trial. When a node was detected, a puncture was performed under real-time ultrasound control. The primary end point was the number of successful biopsy specimens. Diagnostic results from the biopsies were compared with operative findings. Lymph node stations were classified according to the recently adopted American Thoracic Society scheme. Results: From 502 patients (316 men) of mean age 59 years (range 24–82), 572 Lymph Nodes were punctured and 535 (94%) resulted in a diagnosis. Biopsy specimens were taken from Lymph Nodes in region 2L (40 Nodes), 2R (53 Nodes), 3 (35 Nodes), 4R (86 Nodes), 4L (77 Nodes), 7 (127 Nodes), 10R (38 Nodes), 10L (43 Nodes), 11R (40 Nodes) and 11L (33 Nodes). The mean (SD) diameter of the Nodes was 1.6 (0.36) cm and the range was 0.8–3.2 cm (SD range 0.8–4.3). Sensitivity was 94%, specificity 100%, and the positive predictive value was 100% calculated per patient. No complications occurred. Conclusion: EBUS-TBNA is a promising new method for sampling mediastinal Lymph Nodes. It appears to permit more and smaller Nodes to be sampled than conventional TBNA, and it is safe.
Christine Moussion - One of the best experts on this subject based on the ideXlab platform.
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hevs Lymphatics and homeostatic immune cell trafficking in Lymph Nodes
Nature Reviews Immunology, 2012Co-Authors: Jeanphilippe Girard, Christine Moussion, Reinhold ForsterAbstract:The recirculation of Lymphocytes through Lymph Nodes and their encounter with dendritic cells is crucial for immunity. Here, the authors review the role of high endothelial venules, Lymphatics and Lymph node stroma in the trafficking of immune cells in Lymph Nodes during homeostasis.
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dendritic cells control Lymphocyte entry to Lymph Nodes through high endothelial venules
Nature, 2011Co-Authors: Jeanphilippe Girard, Christine MoussionAbstract:Christine Moussion and Jean-Philippe Girard report that dendritic cells in the immune system have an unexpected immune surveillance role in Lymphocyte recirculation during homeostasis. Lymphotoxin ligands derived from dendritic cells promote the growth of high endothelial venules — blood vessels specialized in Lymphocyte recruitment — which control the entry of naive Lymphocytes from the blood into Lymph Nodes. While patrolling the body in search of foreign antigens, naive Lymphocytes continuously circulate from the blood, through the Lymph Nodes, into the Lymphatic vessels and back to the blood1,2. This process, called Lymphocyte recirculation, provides the body with effective immune surveillance for foreign invaders and for alterations to the body’s own cells. However, the mechanisms that regulate Lymphocyte recirculation during homeostasis remain incompletely characterized. Here we show that dendritic cells (DCs), which are well known for their role in antigen presentation to T Lymphocytes3, control the entry of naive Lymphocytes to Lymph Nodes by modulating the phenotype of high endothelial venules (HEVs), which are blood vessels specialized in Lymphocyte recruitment2,4,5. We found that in vivo depletion of CD11c+ DCs in adult mice over a 1-week period induces a reduction in the size and cellularity of the peripheral and mucosal Lymph Nodes. In the absence of DCs, the mature adult HEV phenotype reverts to an immature neonatal phenotype, and HEV-mediated Lymphocyte recruitment to Lymph Nodes is inhibited. Co-culture experiments showed that the effect of DCs on HEV endothelial cells is direct and requires Lymphotoxin-β-receptor-dependent signalling. DCs express Lymphotoxin, and DC-derived Lymphotoxin is important for Lymphocyte homing to Lymph Nodes in vivo. Together, our results reveal a previously unsuspected role for DCs in the regulation of Lymphocyte recirculation during immune surveillance.
Changjun Wu - One of the best experts on this subject based on the ideXlab platform.
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Differentiation of metastatic cervical Lymph Nodes with ultrasound elastography by virtual touch tissue imaging
Journal of Ultrasound in Medicine, 2015Co-Authors: Dehong Che, Xian Li Zhou, Mei Ling Sun, Zhaopeng Jiang, Xiao Wang, Changjun WuAbstract:OBJECTIVES: The purpose of this study was to investigate the clinical usefulness of acoustic radiation force impulse elastography for the differential diagnosis of cervical Lymph Nodes.\n\nMETHODS: Virtual touch tissue imaging (Siemens Medical Solutions, Mountain View, CA) was analyzed in 81 patients (mean age, 46.6 years; range, 5-82 years) with 81 Lymph Nodes (45 metastatic Nodes and 36 benign Nodes).\n\nRESULTS: Most benign Lymph Nodes were slightly darker or the same in brightness compared with surrounding tissue, whereas most metastatic Nodes were obviously darker. The mean area ratio of benign Lymph Nodes ± SD (1.05 ± 0.15) was statistically lower than the mean area ratio of metastatic Lymph Nodes (1.39 ± 0.20; P < 0.001). The area ration cutoff level for metastatic Lymph Nodes was estimated to be 1.16. With the use of a receiver operating characteristic curve with this cutoff value, the area ratio predicted malignancy with sensitivity of 91.1%, specificity of 83.3%, and an area under the curve of 0.925.\n\nCONCLUSIONS: Acoustic radiation force impulse imaging is feasible for cervical Lymph Nodes. The Virtual Touch tissue imaging technique can complement conventional sonography, thereby making it easier to diagnose cervical Lymph Nodes.
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Initial experience of acoustic radiation force impulse ultrasound imaging of cervical Lymph Nodes
European Journal of Radiology, 2013Co-Authors: Wei Meng, Ping Xing, Qi Chen, Changjun WuAbstract:The aim of this study was to evaluate acoustic radiation force impulse imaging for cervical Lymphadenopathy in routine clinical practice and to correlate the acoustic radiation force impulse values with the morphological signs and the pathological results, which were used as the reference standard. The virtual touch tissue quantification values were analyzed in 123 patients (mean age 40.8 years, range 1-81 years) with 181 cervical Lymph Nodes (87 benign, 94 malignant). The diagnostic performance of acoustic radiation force impulse values were evaluated with respect to sensitivity, specificity, and area under the curve using a receiver operating characteristic curve analysis. The mean virtual touch tissue quantification values of the benign lesions (2.01 ± 0.95 m/s) differed from that of the malignant lesions (4.61 ± 2.56 m/s; P < 0.001). The cutoff level for virtual touch tissue quantification value for malignancy was estimated to be 2.595 m/s. Using the receiver operating characteristic curve curves with the cutoff value, the virtual touch tissue quantification value predicted malignancy with a sensitivity of 82.9%, specificity of 93.1% and gave an areas under the curve of 0.906 (95% CI 0.857-0.954). Acoustic radiation force impulse is feasible for cervical Lymph Nodes and provides quantitative elasticity measurements, which may complement B-mode ultrasound and potentially improve the characterization of cervical Lymph Nodes. © 2013 Elsevier Ireland Ltd.
