bluuebunny/crossref_metadata_2025_split huggingface dataset:
Real‐time monitoring of radiofrequency ablation of rabbit liver by respiratory‐gated quantitative temperature MRI
Authors: Lepetit‐Coiffé Matthieu , Quesson Bruno , Seror Olivier , Dumont Erik , Le Bail Brigitte , Moonen Chrit T. W. , Trillaud Hervé 
Published: June 2006

AbstractPurposeTo evaluate the feasibility and precision of magnetic resonance imaging (MRI) thermometry for monitoring radiofrequency (RF) liver ablation in vivo and predicting the size of the ablation zone.Materials and MethodsAt 1.5T, respiratory‐triggered real‐time MR temperature mapping (the proton resonance frequency (PRF) method) was used to monitor RF ablation in rabbit liver (N = 6) under free breathing. The size of the ablation zones, as assessed by histological analyses, was compared with that predicted from MR thermal dose (TD) maps or derived from conventional T1‐weighted (T1w), T2‐weighted (T2w), and T1w gadolinium (Gd)‐enhanced (T1w‐Gd) images acquired immediately after the ablation, and on days 4 and 8 postprocedure.ResultsMR temperature uncertainty remained under 1–2°C even during RF deposition. The TD maps were shown to be more predictive and precise than the other MR images, with an average predictive precision for the final ablation zone size of about 1 mm as compared to the histologically proven lesion on day 8.ConclusionQuantitative temperature MRI during RF ablation is feasible and offered a precise indication of the ablation zone size in this preclinical study based on the lethal dose threshold. J. Magn. Reson. Imaging 2006. © 2006 Wiley‐Liss, Inc.
Background suppression in time‐resolved MR angiography without mask acquisition or operator intervention
Authors: Arunachalam Arjun , Thornton Frank J. , Block Walter. F. 
Published: June 2006

AbstractPurposeTo suppress static and background tissue in time‐resolved MRA studies of the full thorax or abdomen without the need of a mask image or operator intervention.Materials and MethodsThe time course of each voxel is projected onto the orthogonal complement space of a matrix that spans static and linearly enhancing signal vectors. The norm of the solution, or the projection length, acts as a confidence measure for segmenting vascular and nonvascular tissue. Voxels whose confidence measures fall below an automatically detected threshold value are considered nonvascular. These voxels undergo an increasing level of suppression as the distance of the confidence measure from the threshold grows.ResultsMIPs of processed volunteer studies were compared to the original unaltered studies to assess the improvement in clarity of vascular structures. Qualitative and quantitative comparisons of full body MIPs verify excellent suppression of nonvascular tissue in time‐resolved three‐dimensional image volumes.ConclusionContrast increased by an average factor of 13 in five volunteer studies, quantitatively emphasizing the improvement in MIP processing achieved by this method. Improvement in the clarity of vascular structures in subvolume MIPs is also demonstrated to emphasize the significant increase in ease with which regions of interest can be identified. J. Magn. Reson. Imaging 2006. © 2006 Wiley‐Liss, Inc.
q‐space analysis of lung morphometry in vivo with hyperpolarized3He spectroscopy
Authors: Shanbhag Dattesh D. , Altes Talissa A. , Miller G.Wilson , Mata Jaime F. , Knight‐Scott Jack 
Published: June 2006

AbstractPurposeTo examine the utility of a3He spectroscopic q‐space technique for detecting changes in lung morphometry in vivo.Materials and MethodsA diffusion‐weighted spectroscopy sequence was used to collect global diffusion data from healthy adults (N= 11), healthy children (N= 5), and chronic obstructive pulmonary disease (COPD) patients (N= 2) using 40 cc of hyperpolarized3He gas within a two second breathhold. Displacement probability profiles (DPP) were obtained by Fourier transformation of diffusion data with respect to q. A bi‐Gaussian model was used to decompose the DPPs into narrow and broad components, characterized by root‐mean‐square displacements Xrms1and Xrms2, respectively.ResultsIn healthy adults, the narrow component (Xrms,1) of the DPP had a mean displacement of 188 ± 10 μm, slightly less than the reported average size of the alveoli. The broad component (Xrms,2) had a mean value of 474 ± 44 μm, comparable to the diameter of the respiratory bronchioles in the acinus. In children, both Xrms1(167 ± 4 μm) and Xrms2(382 ± 22 μm) compared to healthy adults (P< 0.01). In COPD patients, the mean displacements were elevated (Xrms1: 265 ± 71 μm; Xrms2: 530 ± 109 μm) compared to healthy adults. Excellent correlation was found between rms displacements and age (age vs. Xrms,1: r = 0.78,P< 0.001; age vs. Xrms,2: r = 0.90,P< 0.001).ConclusionThe q‐space parameters agreed remarkably well with published alveolar morphometry data. The results suggest that the technique may be sensitive to disease, as evident from the elevated mean displacements in COPD patients compared to healthy volunteers. Detailed lung microstructural information can be obtained using a very low volume of inhaled3He. J. Magn. Reson. Imaging 2006. © 2006 Wiley‐Liss, Inc.
Structural conformation and vibrational spectroscopic studies of 2,6‐bis(p‐N,N‐dimethyl benzylidene)cyclohexanone using density functional theory
Authors: James C. , Raj A. Amal , Reghunathan R. , Jayakumar V. S. , Joe I. Hubert 
Published: June 2006

AbstractNIR‐FT Raman and FT‐IR spectra of the crystallized 2,6‐bis (p‐N,N‐dimethyl benzylidene)cyclohexanone (C24H28N2O) have been recorded in the region 3200–500 and 4000–400 cm−1, respectively. The spectral interpretation has been done following full structure optimization and vibrational wavenumber calculations based on the density functional theory (DFT) using the standard B3LYP/6‐31G* basis set. The predicted vibrational spectra are in excellent agreement with the experiment, permitting an unambiguous assignment for the unusual downshifting of νCO caused by expanded conjugation effects in the dienone system. The optimized geometry clearly demonstrates the ‘half‐chair’ conformation of the central nonheterocyclic ring. The ring CH stretching vibrational modes involving aromatic hydrogen atoms participating in steric interaction have been observed with low intensities. There are valid structural and spectral bases for the enhancement of its bioactivity due to full charge transfer reaction by the substitution of the electron‐donating 4‐dimethylamino group into the aryl rings. The existence of intramolecular, CH…O, improper, blue‐shifted hydrogen bond was investigated by means of the natural bonding orbitals (NBO) analysis. There are also slight dissimilarities in the bond lengths and endocyclic bond angles of both phenyl rings due to the effect of the heavy substitution. The characteristic ring modes have also been assigned in detail. Copyright © 2006 John Wiley & Sons, Ltd.
Allergen‐specific IgE testing in the diagnosis of food allergy and the event of a positive match in the bioinformatics search
Authors: van Ree Ronald , Vieths Stefan , Poulsen Lars K. 
Published: June 2006

AbstractCurrent documents on risk assessment of genetically modified foods recommend including IgE‐binding tests on sera from allergic patients. However, there is no generally accepted recommendation on technical aspects of the testing procedures or on the interpretation of the results, despite that fact that both false positive and false‐negative results may be caused by variability of the test procedures. The present article discusses the state‐of‐the‐art of serological test procedures for qualitative and quantitative determination of specific IgE and interpretation of test results. It is emphasized that the use of sera from clinically well‐characterized subjects is of high importance. In the case of a positive test result, the biological activity of the detected IgE antibodies, i. e., the potential to trigger mediator release from basophils or mast cells in an allergen‐specific manner, should be taken into account. However, present data also indicate that validation of such mediator release tests is required, both in terms of experimental protocols and with respect to correlation of the test results with the clinical situation. Further studies are also required to prove the usefulness of targeted serum screening, i. e., the testing of gene products from organisms not known to be allergenic with sera from subjects allergic to related species.
Allergen sequence databases
Authors: Gendel Steven M. , Jenkins John A. 
Published: June 2006

AbstractA number of specialized databases have been developed to facilitate studies of human allergens. These include molecular databases focused on protein sequences and structures, informational databases focused on clinical, biochemical and epidemiological data related to protein allergens, a database on allergen nomenclature, and other knowledge bases or informational websites that are peripherally‐related to research on allergens. Examples of each type of databases are listed and described briefly in this review. Database construction and maintenance and their impact on database quality and usefulness are also discussed.
Structural bioinformatic approaches to understand cross‐reactivity
Authors: Breiteneder Heimo , Mills Clare 
Published: June 2006

AbstractCross‐reactivity of allergens results from the presence of antibody‐accessible conserved surface structures. These can best be studied when allergens have been structurally defined by X‐ray crystallography or another structure determination method. When this is not the case, mimotope technology provides a useful alternative for elucidating antibody‐binding sites on allergens. Structural bioinformatic approaches have been used to study the cross‐reactivity of inhalant allergens with labile food allergens (Bet v 1 family) as well as the cross‐reactivity between stable food allergens such as members of the nonspecific lipid transfer protein family. It was found that the degree of similarity of the structures correlated with the observed IgE cross‐reactivities. However, IgE cross‐reactivity between structurally unrelated allergens has not been demonstrated to date.
Regional variations in intramyocellular lipid concentration correlate with muscle fiber type distribution in rat tibialis anterior muscle
Authors: De Feyter Henk M.M.L. , Schaart Gert , Hesselink Matthijs K. , Schrauwen Patrick , Nicolay Klaas , Prompers Jeanine J. 
Published: June 2006

Abstract1H MR spectroscopy (MRS) has proved to be a valuable noninvasive tool to measure intramyocellular lipids (IMCL) in research focused on insulin resistance and type II diabetes in both humans and rodents. An important determinant of IMCL is the muscle fiber type, since oxidative type I fibers can contain up to three times more IMCL than glycolytic type II muscle fibers. Because these different muscle fiber types are inhomogeneously distributed in rodent muscle, in the present study we investigated the distribution of IMCL within the rat tibialis anterior muscle (TA) in vivo using single‐voxel 1H MRS along with the muscle fiber distribution in the TA ex vivo determined from immunohistological assays. IMCL levels in the TA differed by up to a factor of 3 depending on the position of the voxel. The distribution of IMCL over the TA cross section was not random, but emerged in a pattern similar to the distribution of the predominantly oxidative muscle fiber types. Dietary interventions, such as high‐fat feeding and 15 hr of fasting, did not significantly change this typical fiber type‐dependent pattern of IMCL content. These results stress the importance of voxel positioning when single‐voxel 1H MRS is used to study IMCL in rodent muscle. Magn Reson Med, 2006. © 2006 Wiley‐Liss, Inc.
Chromium(VI) as a novel MRI contrast agent for cerebral white matter: Preliminary results in mouse brain in vivo
Authors: Watanabe Takashi , Tammer Roland , Boretius Susann , Frahm Jens , Michaelis Thomas 
Published: June 2006

AbstractThis work demonstrates that intraventricular microinjections of a low dose of potassium dichromate (0.4 μL of 10 mM solution) yield a specific contrast enhancement of white matter (WM) tracts in T1‐weighted 3D MRI of mouse brain in vivo. Pronounced and persistent signal increases (40–100% at 24 hr after injection) were observed in the corpus callosum, anterior commissure, fornix, and stria medullaris, as well as in the mammillothalamic tract and fasciculus retroflexus. These results suggest that the extracellular diffusion of diamagnetic chromium(VI) (Cr(VI)) after injection is followed by a tissue‐specific reduction to paramagnetic Cr(V) and (III), which relies predominantly on the oxidation of myelin lipids. Because Cr(VI)‐induced contrast leads to only a mild unspecific enhancement (10–20%) of gray matter (GM) structures, such as the hippocampal formation, the method reveals novel information that differs from that obtainable using other paramagnetic ions, such as manganese. Magn Reson Med, 2006. © 2006 Wiley‐Liss, Inc.
Task‐modulation of functional synchrony between spontaneous low‐frequency oscillations in the human brain detected by fMRI
Authors: Xu Guofan , Xu Yin , Wu Gaohong , Antuono Piero G. , Hammeke Thomas A. , Li Shi‐Jiang 
Published: June 2006

AbstractRecent developments in functional MRI (fMRI) technology with high spatial and temporal resolution have made it possible to noninvasively detect spontaneous low‐frequency oscillations (SLOs) and quantify their functional synchrony in the human brain. In the present fMRI study the dynamic characteristics of the functional synchrony between SLOs were quantitatively determined by the phase shift index (PSI). With the use of an fMRI‐guided voxel‐selection method, the SLOs and their functional synchrony were found to be modulated by different memory tasks. The results demonstrate that SLOs in episodic memory‐related circuitry have significantly higher synchrony during the performance of declarative memory‐encoding activities compared to nondeclarative memory‐encoding activities. It is suggested that the dynamic property of SLOs and the quantitative assessment of their functional synchrony could be utilized as a biomarker to noninvasively characterize localized pathophysiological functions in the human brain. Magn Reson Med, 2006. © 2006 Wiley‐Liss, Inc.
General algorithm for automated off‐center MRI
Authors: Magland J. , Wehrli F.W. 
Published: June 2006

AbstractA general formula was derived that automatically modifies any MRI pulse sequence to realize arbitrary field‐of‐view (FOV) shifts. Unlike conventional techniques for implementing off‐center MRI, the new method is completely automatic and can therefore be incorporated into the scanner hardware or software, thereby simplifying the development of MRI pulse sequences. The algorithm was incorporated into a visual pulse sequence programming environment, and several pulse sequences were programmed and tested at various off‐center locations using the new technique. Unless there is significant background field inhomogeneity or gradient nonlinearity, research sequences employing the automatic technique need only be programmed and tested at the gradient isocenter, whereas with conventional methods, artifacts can sometimes depend on the position of the FOV. Magn Reson Med, 2006. © 2006 Wiley‐Liss, Inc.
Application of parallel imaging to fMRI at 7 Tesla utilizing a high 1D reduction factor
Authors: Moeller Steen , Van de Moortele Pierre‐Francois , Goerke Ute , Adriany Gregor , Uǧurbil Kâmil 
Published: June 2006

AbstractGradient‐echo EPI, blood oxygenation level‐dependent (BOLD) functional MRI (fMRI) using parallel imaging (PI) is demonstrated at 7 Tesla with 16 channels, a fourfold 1D reduction factor (R), and fourfold maximal aliasing. The resultant activation detection in finger‐tapping fMRI studies was robust, in full agreement with expected activation patterns based on prior knowledge, and with functional maps generated from full field of view (FOV) coverage of k‐space using segmented acquisition. In all aspects the functional maps acquired with PI outperformed segmented coverage of full k‐space. With a 1D R of 4, fMRI activation based on PI had higher statistical significance, up to 1.6‐fold in an individual case and 1.25 ± .25 (SD) fold when averaged over six studies, compared to four‐segment/full‐FOV data in which the

reduction in the image signal‐to‐noise ratio (SNR) due to k‐space undersampling was compensated for by acquiring additional repetitions of the undersampled k‐space. When this compensation for
loss in SNR was not performed, the effect of PI was determined by the ratio of physiologically induced vs. intrinsic (thermal) noise in the fMRI time series and the extent to which physiological “noise” was amplified by the use of segmentation in the full‐FOV data. The results demonstrate that PI is particularly beneficial at this ultrahigh field strength, where both the intrinsic image SNR and temporal signal fluctuations due to physiological processes are large. Magn Reson Med, 2006. © 2006 Wiley‐Liss, Inc.
Cardiac fat navigator‐gated steady‐state free precession 3D magnetic resonance angiography of coronary arteries
Authors: Nguyen Thanh D. , Spincemaille Pascal , Prince Martin R. , Wang Yi 
Published: June 2006

AbstractMotion artifacts and the lack of accurate detection of cardiac motion present a major challenge for high‐resolution cardiac MRI. Recently a multidimensional cardiac fat navigator was proposed to provide a fast and direct measurement of bulk cardiac motion. The objective of this study was to demonstrate the feasibility of employing the cardiac fat navigator in balanced steady‐state free precession (SSFP) free‐breathing 3D coronary MRA (CMRA). The cardiac fat navigator echo is optimized to provide both motion monitoring and epicardial fat suppression. Steady‐state magnetization preparation, which is needed for SSFP CMRA, is optimized by comparing three preparation schemes: α/2, linear ramp with 20 RF pulses (20LR), and Kaiser ramp with six RF pulses (6KR). The present preliminary human study shows that the 6KR preparation provides better image quality than both the α/2 (P < 0.0025) and the 20LR preparations (P < 0.025) for free‐breathing SSFP 3D CMRA (N = 11). Magn Reson Med, 2006. © 2006 Wiley‐Liss, Inc.
Improved deconvolution of perfusion MRI data in the presence of bolus delay and dispersion
Authors: Willats Lisa , Connelly Alan , Calamante Fernando 
Published: June 2006

AbstractCerebral blood flow (CBF) is commonly estimated from the maximum of the residue function deconvolved from bolus‐tracking data. The bolus may become delayed and/or dispersed in the vessels feeding the tissue, resulting in the calculation of an effective residue function,Reff(t), whose shape reflects the distortion of the bolus as well as the hemodynamic tissue status. Consequently the CBF is often underestimated. Since regularizing the deconvolution introduces additional distortions toReff(t), it is impossible to distinguish a true decrease in the CBF from bias introduced by abnormal vasculature. This may result in misidentification of tissue regions at risk of infarction, which could have serious clinical consequences. We propose a modified maximum‐likelihood expectation‐maximization (mML‐EM) method, which is shown by way of simulations to improve the characterization ofReff(t) across a wide range of shapes. Apointwisetermination approach for the iteration minimizes the effects of noise, and appropriate integral approximations minimize discretization errors. mML‐EM was applied to data from a patient with left internal carotid artery (ICA) occlusion. The shape of each calculatedReff(t) was used to create a map indicating voxels affected by bolus delay and/or dispersion, where CBF estimates are inherently unreliable. Such maps would be a useful adjunct for interpreting bolus‐tracking data. Magn Reson Med, 2006. © 2006 Wiley‐Liss, Inc.
Optimizing the efficiency of high‐field multivoxel spectroscopic imaging by multiplexing in space and time
Authors: Goelman Gadi , Liu Songtao , Hess David , Gonen Oded 
Published: June 2006

AbstractA new strategy to yield information from the maximum number of voxels, each at the optimum signal‐to‐noise ratio (SNR) per unit time, in MR spectroscopic imaging (MRSI) is introduced. In the past, maximum acquisition duty‐cycle was obtained by multiplexing in time several single slices each repetition time (TR), while optimal SNR was achieved by encoding the entire volume of interest (VOI) each TR. We show that optimal SNR and acquisition efficiency can both be achieved simultaneously by multiplexing in space and time several slabs of several slices, each. Since coverage of common VOIs in 3D proton MRSI in the human brain typically requires eight or more slices, at 3 T or higher magnetic fields, two or more slabs can fit into the optimum TR (∼1.6 s). Since typically four or less slices would then fit into each slab, Hadamard encoding is favored in that direction for slice profile reasons. It is demonstrated that per fixed examination length, the new method gives, at 3 T, twice as many voxels, each of the same SNR and size, compared with current 3D chemical shift imaging techniques. It is shown that this gain will increase for more extensive spatial coverage or higher fields. Magn Reson Med, 2006. © 2006 Wiley‐Liss, Inc.
Large granular lymphocyte leukemia (LGL) in a child with hyper IgM syndrome and autoimmune hemolytic anemia
Authors: Kitchen Brenda J. , Boxer Laurence A. 
Published: June 2006

AbstractWe describe a female with a history of autosomal recessive hyper‐IgM (HIGM) syndrome along with a history of autoimmune hemolytic anemia and intermittent lymphadenopathy. She subsequently developed neutropenia, lymphocyostosis and mild thrombocytopenia. Flow cytometry of the peripheral blood revealed the presence of a marked predominance of cytotoxic T lymphocytes, shown to be clonal, with concomitant natural killer (NK) antigen expression. She responded to weekly methotrexate therapy. Pediatr Blood Cancer 2008;50:142–145. © 2006 Wiley‐Liss, Inc.
Risk of a second malignant neoplasm among 5‐year survivors of cancer in childhood and adolescence in British Columbia, Canada
Authors: MacArthur Amy C. , Spinelli John J. , Rogers Paul C. , Goddard Karen J. , Phillips Norm , McBride Mary L. 
Published: June 2006

AbstractBackgroundWe examined second malignancies, a recognized late effect of therapy among survivors of childhood and adolescent cancer, among a recent, population‐based cohort of 2,322 5‐year survivors diagnosed before 20 years of age in British Columbia (BC), Canada between 1970 and 1995.ProcedureSurvivors and second malignancies were identified from the BC Cancer Registry. Risk of second malignancy was evaluated using standardized incidence ratios (SIRs), absolute excess risk (AER), and cumulative risk. The effect of demographic, temporal, and disease‐related characteristics on risk was assessed.ResultsFifty‐five second malignancies were observed after 26,071 person‐years of follow‐up. Relative rate of developing a second malignancy among survivors was 5 times higher than expected (SIR = 5.0, 95% CI, 3.8–6.5), and absolute excess risk was 1.7 deaths per 1,000 person‐years. Cumulative incidence of a second malignancy was 5.1% at 25 years after diagnosis of the first cancer. SIRs and absolute excess risk of subsequent cancer was higher among females (SIR = 5.9, 95% CI, 4.5–8.3 and AER = 2.66). While relative risk of second cancer was higher for those diagnosed before 10 years of age (SIR = 10.6, 95% CI, 7.1–16.0), absolute excess risk was slightly higher for those diagnosed after 10 years of age. SIRs were significantly elevated for all follow‐up periods, but absolute excess risk of a second cancer was highest among patients surviving more than 15 years.ConclusionsIncreased risk of a subsequent neoplasm is evident among childhood cancer survivors diagnosed in more recent periods than has been previously reported, continues years after diagnosis, and varies according to several risk factors. Continued surveillance is essential to quantify and characterize long‐term and changing risks for appropriate follow‐up. Pediatr Blood Cancer © 2006 Wiley‐Liss, Inc.