bluuebunny/crossref_metadata_2025_split huggingface dataset:
3D TrueFISP imaging of mouse brain at 4.7T and 9.4T
Authors: Miraux Sylvain , Massot Philippe , Ribot Emeline J. , Franconi Jean‐Michel , Thiaudiere Eric 
Published: July 2008

AbstractPurposeTo examine the ability of TrueFISP imaging for evaluating tumor size in mouse brain at high field.Materials and MethodsBrains of healthy and glioma‐implanted nude mice were imaged at 4.7T and 9.4T. 3D imaging was performed with TrueFISP and T2w‐RARE. Radiofrequency pulses with alternating phase and the sum‐of‐squares reconstruction method were used in TrueFISP imaging. The contrast‐to‐noise ratio (CNR) was evaluated in healthy and in tumoral brain regions.ResultsBanding artifact was correctly suppressed in TrueFISP images thanks to the method used. The signal‐to‐noise ratio (SNR) and CNR were comparable in TrueFISP and T2w‐RARE images at 4.7T, but acquisition was around 4 times shorter with TrueFISP. Tumor was well detected at 4.7T with TrueFISP, but CNR between tumor and healthy tissue was low at 9.4T.ConclusionTrueFISP is efficient and fast to perform brain imaging at 4.7T. Multiple TrueFISP acquisitions with phase‐cycled radiofrequency (RF) pulses and sum‐of‐squares reconstruction allow suppression of banding artifact. Tumoral regions were well detected and the method allows longitudinal studies of tumor growth. J. Magn. Reson. Imaging 2008;28:497–503. © 2008 Wiley‐Liss, Inc.
Carcinosarcoma of the uterus: MR findings
Authors: Tanaka Yumiko O. , Tsunoda Hajime , Minami Rie , Yoshikawa Hiroyuki , Minami Manabu 
Published: July 2008

AbstractPurposeTo clarify the imaging characteristics of carcinosarcomas, which are the most common malignant mixed epithelial and mesenchymal tumors (MEMTs) of the uterus.Materials and MethodsWe retrospectively reviewed MR findings of 17 histopathologically confirmed cases with carcinosarcomas, including the size, growth pattern, signal intensity, contrast enhancement, and extrauterine spread in each case.ResultsThe maximum tumor diameter was 11–165 mm (mean 88 mm). Nine cases (53%) showed exophytic with a stalk and eight cases (47%) showed broad‐based exophytic growth. None of them showed invasive growth. Fourteen cases (82%) were isointense and three cases (18%) were hyperintense to myometrium on T1‐weighted images (T1WI). An extremely high intensity area suggesting intratumoral hemorrhage was seen in only two cases. In 15 cases (88%), more than half of the tumor showed higher signal intensity than the outer myometrium on T2WI. Eight of the 16 cases (50%) had an unenhanced area, whereas 13 cases (81%) had a strongly enhanced area. Extrauterine extension was observed in only two cases (12%) at initial presentation.ConclusionUterine carcinosarcomas reveal a spectrum of imaging findings with a high signal on T2WI, with a prolonged intense enhancement being the most common imaging feature. J. Magn. Reson. Imaging 2008;28:434–439. © 2008 Wiley‐Liss, Inc.
Lateral parabrachial afferent areas and serotonin mechanisms activated by volume expansion
Authors: Margatho Lisandra Oliveira , Godino Andrea , Oliveira Fabíola Raquel Tenório , Vivas Laura , Antunes‐Rodrigues José 
Published: August 2008

AbstractRecent evidence has shown that the serotonergic mechanism of the lateral parabrachial nucleus (LPBN) participates in the regulation of renal and hormonal responses to isotonic blood volume expansion (BVE). We investigated the BVE‐induced Fos activation along forebrain and hindbrain nuclei and particularly within the serotonergic clusters of the raphé system that directly project to the LPBN. We also examined whether there are changes in the concentration of serotonin (5HT) within the raphé nucleus in response to the same stimulus. With this purpose, we analyzed the cells doubly labeled for Fos and Fluorogold (FG) following BVE (NaCl 0.15 M, 2 ml/100 g b.w., 1 min) 7 days after FG injection into the LPBN. Compared with the control group, blood volume‐expanded rats showed a significant greater number of Fos‐FG double‐labeled cells along the nucleus of the solitary tract, locus coeruleus, hypothalamic paraventricular nucleus, central extended amygdala complex, and dorsal raphé nucleus (DRN) cells. Our study also showed an increase in the number of serotonergic DRN neurons activated in response to isotonic BVE. We also observed decreased levels of 5HT and its metabolite 5‐hydroxyindoleacetic acid (measured by high‐pressure liquid chromatography) within the raphé nucleus 15 min after BVE. Given our previous evidence on the role of the serotonergic system in the LPBN after BVE, the present morphofunctional findings suggest the existence of a key pathway (DRN‐LPBN) that may control BVE response through the modulation of 5HT release. © 2008 Wiley‐Liss, Inc.
Tumor spectrum of adult intussusception
Authors: Chiang Jy‐Ming , Lin Yann‐Sheng 
Published: July 2008

AbstractIntroductionAdult intussusception is rare. Most general and colorectal surgeons are unfamiliar with its etiology and optimal management.Patients and MethodsPatients older than 16 years and diagnosed with intestinal intussusception between January 1990 and June 2006 were retrospectively reviewed. Data related to presentation, diagnosis, treatment, and pathology were analyzed.ResultsSeventy‐two patients underwent surgery for intestinal intussusception. Neoplasm was identified as the cause of intussusception in 66 (92%) cases, and 6 (8%) were idiopathic. The incidence of malignant colonic intussusception (63%) was significantly higher than that of enteric intussusception (20%), P = 0.001. Primary colon adenocarcinoma (8 of 10 patients, 80%) and malignant lymphoma (2 of 10 patients, 20%) were the two most common underlying malignant lesions in the colon. Lipoma (15 of 40 patients, 38%) and Peutz–Jegher adenoma (10 of 40 patients, 25%) were the two most common lesions of benign small bowel neoplasms while 27% (3 of 11) of malignant enteric intussusception cases were malignant lymphoma and metastatic respectively.ConclusionLipoma is the most common benign tumor in both small and large bowel intussusception. Whereas 80% of tumors associated with small bowel intussusception were benign, two‐thirds of colonic intussusceptions had resulted from primary adenocarcinoma. J. Surg. Oncol. © 2008 Wiley‐Liss, Inc.
Lymphatic fistulae after neck dissection: The fibrin sealant treatment
Authors: Vaiman Michael , Eviatar Efraim 
Published: July 2008

AbstractObjectiveto investigate possibility of treatment of lymphatic fistulae after neck dissection with the fibrin sealant.MethodsDuring the period of 2001–2007, two cases of lymphatic fistulae after neck dissection were treated with human blood based fibrin sealant (Quixil fibrin glue). The sealant components were sprayed into the fistulae with the help of a dual‐syringe delivery system.ResultsSixty patients were operated, 84 neck dissections were performed from 2001 till 2008. Lymphatic fistulae occurred in two cases (2.4% of operations). Fibrin sealant treatment resulted in immediate stop of a leak and complete healing of the fistulae in both cases after 3 days of treatment. One year follow‐up revealed no complications.ConclusionFibrin sealant application might be an effective and time‐saving treatment of lymphatic fistulae after neck dissection. J. Surg. Oncol. © 2008 Wiley‐Liss, Inc.
Methylation‐Related silencing of p14ARF gene correlates with telomerase activity and mRNA expression of human telomerase reverse transcriptase in hepatocellular carcinoma
Authors: Zhang Changsong , Guo Xianling , Zhang Li , Lu Zhenghua , Ma Nannan , Cheng Yue , Shen Feng , Zhang Baihe , Wu Mengchao , Wei Lixin 
Published: August 2008

AbstractBackground and ObjectivesThe p14ARF gene encodes a critical negative regulator of cell cycle progression. And upregulation of telomerase activity has been considered a critical step to tumors. We investigated promoter methylation of p14ARF and expression as well as their effect on hTERT expression and telomerase activity in HCC.MethodsWe studied p14ARF methylation and mRNA in 30 hepatocellular carcinomas and corresponding non‐tumor liver tissues using methylation‐specific PCR. Reverse transcription‐PCR was performed for expression of p14ARF and hTERT. Telomerase activity was performed by TRAP assay.Resultsp14ARF hypermethylation was detected in 16 (53.3%) of HCC and 10 (33.3%) of non‐tumor tissues, and 12 of 16 with methylation were tumor tissues around large size (≥5 cm). p14ARF mRNA was observed in 25%, 80.0%, or 50.0% of tumors with hypermethylated, partially methylated or unmethylated p14ARF promoter, respectively. Among the 16 tumors with p14ARF hypermethylation, all 12 tumors lacking p14ARF mRNA were positive for hTERT expression, while only one of 4 tumors expressing p14ARF mRNA was positive for hTERT expression.Conclusionsp14ARF hypermethylation may contribute to silencing of p14ARF mRNA expression in HCC. Telomerase activity is association with inactivation of the p14ARF–p53 pathway induced by methylation in HCC. J. Surg. Oncol. © 2008 Wiley‐Liss, Inc.
Mixed‐mode hydrophilic interaction/cation‐exchange chromatography (HILIC/CEX) of peptides and proteins
Authors: Mant Colin T. , Hodges Robert S. 
Published: July 2008

AbstractThis review represents a summary of the development and application of a novel mixed‐mode HPLC approach to the separation and analysis of peptides and proteins termed hydrophilic interaction/cation‐exchange chromatography (HILIC/CEX). This approach combines the most advantageous aspects of two widely different separation mechanisms, i.e. a separation based on hydrophilicity/hydrophobicity differences between polypeptides overlaid on a separation based on net charge. Applications described include HILIC/CEX separations of cyclic peptides, α‐helical peptides, random coil peptides and modified or deletion products of synthetic peptides. In addition, the excellent resolving ability of HILIC/CEX for modified histone proteins is described. This approach is shown to represent an excellent complement to RP chromatography (RPC), as well as being a potent analytical tool in its own right.
Synthesis and Association Behaviour of Linear Block Copolymers with Different Microstructures but the Same Composition
Authors: Schmitz Christof , Mourran Ahmed , Keul Helmut , Möller Martin 
Published: August 2008

AbstractThe di‐ and triblock copolymers, P(MAA)‐b‐P(MMA), P(MAA)‐b‐P(BMA), P(MAA)‐b‐P(MAA‐co‐MMA)‐b‐P(MMA) and P(MAA)‐b‐P(MAA‐co‐BMA)‐b‐P(BMA), were synthesised via ATRP in order to study the association behaviour in water via polyelectrolyte titration, fluorescence spectroscopy, dynamic light scattering and scanning force microscopy. P(BMA) block copolymers spontaneously self‐associate into micelles whereas for P(MMA) block copolymers addition of salt is necessary to induce aggregation. Principally, the hydrodynamic radius of the micelles decreases from di‐ to triblock copolymer which was attributed to a different conformation of the random middle block at the core/corona interface.magnified image
Evaluation of MR angiography at 7.0 Tesla MRI using birdcage radio frequency coils with end caps
Authors: Kang Chang‐Ki , Hong Suk‐Min , Han Jae‐Yong , Kim Kyoung‐Nam , Kim Sang‐Hoon , Kim Young‐Bo , Cho Zang‐Hee 
Published: July 2008

AbstractThe purpose of this study was to evaluate the feasibility of MR angiography (MRA) at 7.0 Tesla (T) using optimized birdcage (BC) coils with simple end cap configurations. Shielded 16‐rung high‐pass BC coils were built with identical geometry and compared with different sizes and locations of end caps. To determine whether the end cap configuration was effective, the signal intensity profiles along the superior–inferior (S–I) direction were analyzed in phantom and in vivo human experiments. The effects were also investigated in two‐dimensional (2D) and three‐dimensional (3D) time‐of‐flight (TOF) MRA experiments. The signal intensity profiles showed that B1 homogeneity at the service end, that is, the end cap side, was improved as the diameter of the end caps increased and the end cap became closer to the coil end ring. The results of 2D and 3D TOF experiments showed the best improvement of vessel visibility at the BC coil with an 80% end cap, when compared with BC coils with other end cap sizes or without an end cap. In conclusion, the BC coil with an end cap was effective for improving S–I directional homogeneity and suitable for MRA applications, especially at ultrahigh field MRI, such as 7.0T. Magn Reson Med 60:330–338, 2008. © 2008 Wiley‐Liss, Inc.
Myocardial T measurement in iron‐overloaded thalassemia: An ex vivo study to investigate optimal methods of quantification
Authors: He Taigang , Gatehouse Peter D. , Kirk Paul , Mohiaddin Raad H. , Pennell Dudley J. , Firmin David N. 
Published: July 2008

AbstractMyocardial T measurement has been increasingly used for iron quantification to assess the risk of cardiac complications in thalassemia patients. In this study the noise effects were evaluated along with different curve‐fitting models on an iron overloaded ex vivo heart in order to determine the optimal method of T measurement and to help understand issues affecting reproducibility and accuracy. Gradient multiecho short axis images were acquired with differing numbers of excitations to generate varying signal‐to‐noise ratio (SNR) images. A noise correction method was implemented; linear and nonlinear curve‐fitting algorithms were compared and different curve‐fitting models (monoexponential, truncation, baseline subtraction, and offset) were evaluated. This study suggests that the T decay curve in an ex vivo heart can be fitted by a monoexponential model and accurate T measurements can be obtained with proper noise correction. With MRI noise, T is generally overestimated by including late low SNR data points, but underestimated by the offset or baseline subtraction models, which are in fact equivalent. In this situation the truncation model proves to be reproducible and more accurate than the other models. The study also shows that the nonlinear algorithm is preferred in T curve fitting. Magn Reson Med 60:350–356, 2008. © 2008 Wiley‐Liss, Inc.
Effect of feature extraction for brain tumor classification based on short echo time 1H MR spectra
Authors: Luts Jan , Poullet Jean‐Baptiste , Garcia‐Gomez Juan M. , Heerschap Arend , Robles Montserrat , Suykens Johan A. K. , Huffel Sabine Van 
Published: July 2008

AbstractThis study examines the effect of feature extraction methods prior to automated pattern recognition based on magnetic resonance spectroscopy (MRS) for brain tumor diagnosis. Since individual inspection of spectra is time‐consuming and requires specific spectroscopic expertise, the introduction of clinical decision support systems (DSSs) is expected to strongly promote the clinical use of MRS. This study focuses on the feature extraction step in the preprocessing protocol of MRS when using a DSS. On two independent data sets, encompassing single‐voxel and multi‐voxel data, it is observed that the use of the full spectra together with a kernel‐based technique, handling high dimensional data, or using an automated pattern recognition method based on independent component analysis or Relief‐F achieves accurate performances. In addition, these approaches have low cost and are easy to automate. When sophisticated quantification methods are used in a DSS, user interaction should be minimized. The computationally intensive quantification techniques do not tend to increase the performance in these circumstances. The results suggest to simplify the feature reduction step in the preprocessing protocol when using a DSS purely for classification purposes. This can greatly speed up the execution of classifiers and DSSs and may accelerate their introduction into clinical practice. Magn Reson Med 60:288–298, 2008. © 2008 Wiley‐Liss, Inc.
Imaging pH using the chemical exchange saturation transfer (CEST) MRI: Correction of concomitant RF irradiation effects to quantify CEST MRI for chemical exchange rate and pH
Authors: Sun Phillip Zhe , Sorensen A. Gregory 
Published: July 2008

AbstractChemical exchange saturation transfer (CEST) MRI has been shown capable of detecting dilute labile protons and abnormal tissue glucose/oxygen metabolism, and thus, may serve as a complementary imaging technique to the conventional MRI methods. CEST imaging, however, is also dependent on experimental parameters such as the power, duration, and waveform of the irradiation RF pulse. As a result, its sensitivity and specificity for microenvironment properties such as pH is not optimal. In this study, the dependence of CEST contrast on experimental parameters was solved and an iterative compensation algorithm was proposed that corrects the experimentally measured CEST contrast from the concomitant RF irradiation effects. The proposed algorithm was verified with both numerical simulation and experimental measurements from a tissue‐like pH phantom, and showed that pH derived from the compensated CEST imaging agrees reasonably well with pH‐electrode measurements within 0.1 pH unit. In sum, our study validates the use of a correction algorithm to compensate CEST imaging from concomitant RF irradiation effects for accurate calibration of the chemical exchange rate, and demonstrates the feasibility of pH imaging with CEST MRI. Magn Reson Med 60:390–397, 2008. © 2008 Wiley‐Liss, Inc.
Evaluation of MRI models in the measurement of CMRO2 and its relationship with CBF
Authors: Lin Ai‐Ling , Fox Peter T. , Yang Yihong , Lu Hanzhang , Tan Li‐Hai , Gao Jia‐Hong 
Published: July 2008

AbstractThe aim of this study was to investigate the various MRI biophysical models in the measurements of local cerebral metabolic rate of oxygen (CMRO2) and the corresponding relationship with cerebral blood flow (CBF) during brain activation. This aim was addressed by simultaneously measuring the relative changes in CBF, cerebral blood volume (CBV), and blood oxygen level dependent (BOLD) MRI signals in the human visual cortex during visual stimulation. A radial checkerboard delivered flash stimulation at five different frequencies. Two MRI models, the single‐compartment model (SCM) and the multicompartment model (MCM), were used to determine the relative changes in CMRO2 using three methods: [1] SCM with parameters identical to those used in a prior MRI study (M = 0.22; α = 0.38); [2] SCM with directly measured parameters (M from hypercapnia and α from measured δCBV and δCBF); and [3] MCM. The magnitude of relative changes in CMRO2 and the nonlinear relationship between CBF and CMRO2 obtained with Methods [2] and [3] were not in agreement with those obtained using Method [1]. However, the results of Methods [2] and [3] were aligned with positron emission tomography findings from the literature. Our results indicate that if appropriate parameters are used, the SCM and MCM models are equivalent for quantifying the values of CMRO2 and determining the flow‐metabolism relationship. Magn Reson Med 60:380–389, 2008. © 2008 Wiley‐Liss, Inc.
Alias‐free image reconstruction using Fresnel transform in the phase‐scrambling Fourier imaging technique
Authors: Ito Satoshi , Yamada Yoshifumi 
Published: July 2008

AbstractAn image reconstruction technique that reduces aliasing artifacts by scalable image reconstruction in magnetic resonance imaging (MRI) is proposed. The signal obtained by the phase‐scrambling Fourier transform (PSFT) imaging technique can be transformed to the signal described in the Fresnel transform equation of the objects. Therefore, image reconstruction can be performed not only by inverse FT but also by inverse Fresnel transform. When a phase‐scrambling coefficient is given in a certain range, image reconstruction by inverse Fresnel transform allows shrinking of images over rather wide scales. Thus, reduced aliasing images can be reconstructed even from signals that produce serious aliasing artifacts by standard inverse FT reconstruction. Simulation and experimental studies reveal that the proposed method can be used to produce reduced aliasing images. Magn Reson Med 60:422–430, 2008. © 2008 Wiley‐Liss, Inc.
Fat‐water separation with alternating repetition time balanced SSFP
Authors: Çukur Tolga , Nishimura Dwight G. 
Published: July 2008

AbstractBalanced SSFP achieves high SNR efficiency, but suffers from bright fat signal. In this work, a multiple‐acquisition fat‐water separation technique using alternating repetition time (ATR) balanced SSFP is proposed. The SSFP profile can be modified using alternating repetition times and appropriate phase cycling to yield two spectra where fat and water are in‐phase and out‐of‐phase, respectively. The signal homogeneity and the broad width of the created in‐phase and out‐of‐phase profiles lead to signal cancellation over a broad stop‐band. The stop‐band suppression is achieved for a wide range of flip angles and tissue parameters. This property, coupled with the inherent flexibility of ATR SSFP in repetition time selection, makes the method a good candidate for fat‐suppressed SSFP imaging. The proposed method can be tailored to achieve a smaller residual stop‐band signal or a decreased sensitivity to field inhomogeneity depending on application‐specific needs. Magn Reson Med 60:479–484, 2008. © 2008 Wiley‐Liss, Inc.
Numerical solution of Helmholtz equation by the modified Hopfield finite difference techniques
Authors: Dehghan Mehdi , Nourian Mojtaba , Menhaj Mohammad B. 
Published: July 2008

AbstractOne property of the Hopfield neural networks is the monotone minimization of energy as time proceeds. In this article, this property is applied to minimize the energy functions obtained by finite difference techniques of the Helmholtz‐equation. The mathematical representation and correlation between finite difference techniques and modified Hopfield neural networks of the Helmholtz equation are presented. Significant advantages of the above method are its parallel, robust, easy programming nature, and ability of direct hardware implementation. Results of numerical simulations are described and analyzed to demonstrate the method. The results obtained using the proposed method show a very good agreement with theoretical and numerical solutions. © 2008 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2009
A priori and a posteriori error estimations for the dual mixed finite element method of the Navier‐Stokes problem
Authors: Farhloul M. , Nicaise S. , Paquet L. 
Published: July 2008

AbstractThis article is concerned with a dual mixed formulation of the Navier‐Stokes system in a polygonal domain of the plane with Dirichlet boundary conditions and its numerical approximation. The gradient tensor, a quantity of practical interest, is introduced as a new unknown. The problem is then approximated by a mixed finite element method. Quasi‐optimal a priori error estimates are obtained. These a priori error estimates, an abstract nonlinear theory (similar to (Verfürth, RAIRO Model Math Anal Numer 32 (1998), 817–842)) and a posteriori estimates for the Stokes system from (Farhloul et al., Numer Funct Anal Optim 27 (2006), 831–846) lead to an a posteriori error estimate for the Navier‐Stokes system. © 2008 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2009