bluuebunny/crossref_metadata_2025_split huggingface dataset:
Multislice and multicoil phase‐sensitive inversion‐recovery imaging
Authors: Ma Jingfei 
Published: March 2005

AbstractPhase‐sensitive inversion‐recovery (PSIR) imaging may provide enhanced T1 contrast. However, clinical implementation of PSIR imaging is hindered because image reconstruction with this method often lacks robustness and requires manual intervention, particularly for data acquired in multiple slices and with phased‐array coils. In this paper, a new algorithm suitable for automatic PSIR image reconstruction of multislice and multicoil data is presented. This algorithm phase corrects by region‐growing, employing both the magnitude and the phase information of image pixels. Specifically, phase gradients of the original complex image are first calculated and then used to determine the sequence of the region‐growing. The signal direction relating to the phase error for each pixel is then determined during the region‐growing using both the magnitude and the phase of the previously determined pixels that are located within a boxcar neighborhood of the pixel. Finally, the intrinsic intercoil and interslice correlation is exploited to ensure consistency in the global polarity of all of the PSIR images. The results are demonstrated with in vivo human brain images acquired at 3 Tesla with an eight‐channel phased‐array coil. Magn Reson Med 53:904–910, 2005. © 2005 Wiley‐Liss, Inc.
Calculation of left ventricle relative pressure distribution in MRI using acceleration data
Authors: Buyens Fanny , Jolivet Odile , De Cesare Alain , Bittoun Jacques , Herment Alain , Tasu Jean‐Pierre , Mousseaux Elie 
Published: March 2005

AbstractMeasurements of pressure variations within the cardiac chambers could provide important information for clinical assessments of cardiovascular function. In this work an MRI method for evaluating spatial distributions of intracardiac relative pressure is presented. We first calculated pressure gradients from MR maps of blood acceleration by applying the NS equation. We then used an original algorithm to compute pressure distribution in a region of interest (ROI) by minimizing the pressure gradient curl so that the result in a given pixel is independent of the integration path. The method was assessed in five healthy volunteers by means of MR 2D maps of the blood acceleration in the left ventricle (LV) during ejection and filling phases. The pressure variations calculated from acceleration mapping fit the known physiological variations better than those based on velocity maps acquired in the same volunteers. Furthermore, the optimization algorithm presented here produced the same results as iterative algorithms proposed by other authors, but in much less time and without requiring adjustable parameters or boundary conditions. Magn Reson Med 53:877–884, 2005. © 2005 Wiley‐Liss, Inc.
Adrenergic stimulation of Rb+ uptake in pig hearts in vivo assessed by 87Rb MRS
Authors: Kupriyanov V.V. , Xiang B. , Sun J. , Jilkina O. 
Published: March 2005

AbstractIt was previously shown that the adrenergic agonist dobutamine stimulates Rb+ uptake in isolated pig hearts. In the present work we examined whether dobutamine can increase Rb+ uptake rate in vivo. Open‐chest domestic pigs (N = 14) were used under general anesthesia. The surface coil was placed against the anterior left ventricular wall to obtain 87Rb spectra using a spectrometer interfaced with the 7T, 30‐cm horizontal bore magnet. RbCl was infused at the rate of 1.35 ± 0.14 mmol/kg/hr without or with dobutamine (0.6 mg/kg/hr) over a 60‐min period, and then the infusions were terminated. The rate constant (k × 103, from 13 ± 2.4 to 36 ± 12 min−1) and Rb+ influx rate (from 2.5% to 4.8%/min) were increased by dobutamine despite lower plasma [Rb+] (0.59 ± 0.16 vs. 0.84 ± 0.24 mM in control), while the tissue/plasma Rb ratios were identical (38 ± 9). Heart rate (HR) and systolic blood pressure (SBP) were increased from 106 ± 9 to 161 ± 15 bpm (+52%) and from 78 ± 7 to 93 ± 11 mmHg (+19%), respectively. The stimulation of Rb+ uptake by dobutamine is consistent with the activation of Na+/K+ ATPase previously observed in isolated hearts. However, the 50% increase in HR and the double coronary flow caused by the SBP increase and vasodilatation may also contribute to this effect. Magn Reson Med 53:817–822, 2005. © 2005 Wiley‐Liss, Inc.
23Na MRI combined with contrast‐enhanced 1H MRI provides in vivo characterization of infarct healing
Authors: Hillenbrand Hanns B. , Becker Lewis C. , Kharrazian Reza , Hu Kai , Rochitte Carlos E. , Kim Raymond J. , Chen Enn L. , Ertl Georg , Hruban Ralph H. , Lima João A.C. 
Published: March 2005

AbstractAlthough 23Na MRI has been shown to delineate acute myocardial infarction (MI), the time course of in vivo 23Na MRI during infarct healing remains unknown. In this study 23Na MRI was combined with contrast‐enhanced (CE) 1H MRI to noninvasively characterize infarct healing in vivo. Serial in vivo 3D 23Na MRI and 1H MRI were performed for up to 9 weeks postinfarction in 10 dogs. Radioactive microspheres were used to measure myocardial perfusion, and Hematoxylin‐Eosin (H&E) and Masson's trichrome (MT) staining were used to assess interstitial cell infiltrate and collagen content. In vivo 23Na MRI accurately delineated infarct size up to day 5 postinfarction in comparison with 1H MRI (8.9% ± 8.1% vs. 8.6% ± 7.9% on day 1 postinfarction, P = NS; and 6.3% ± 6.2% vs. 6.2% ± 6.2% on days 4/5 postinfarction, P = NS). The in vivo 23Na MRI signal intensity, expressed as the signal intensity ratio of infarcted tissue vs. noninfarcted tissue (MI/R) peaked on day 1 of infarction (2.04 ± 0.23) but decreased significantly to 1.27 at 9 weeks postinfarction (P < 0.05) due to granulation tissue infiltrate and collagen deposition. To confirm the MI/R decrease during scar formation ex vivo, we performed 23Na MRI in 12 rats on day 3 post‐MI (N = 5) and after 6 weeks (N = 7). H&E and Picrosirius Red staining confirmed granulation tissue infiltrate on day 3 and scar formation after 6 weeks. MI/R decreased significantly from 1.91 ± 0.45 on day 3 post‐MI to 1.3 ± 0.09 after 6 weeks. Thus, in vivo 23Na MRI accurately delineates infarct size up to day 5 postinfarction. In vivo 23Na MRI signal intensity decreases during infarct healing as a result of the underlying infarct healing process. Magn Reson Med 53:843–850, 2005. © 2005 Wiley‐Liss, Inc.
1H MR spectroscopy using TE averaged PRESS: A more sensitive technique to detect neurodegeneration associated with Alzheimer's disease
Authors: Hancu Ileana , Zimmerman Earl A. , Sailasuta Napapon , Hurd Ralph E. 
Published: March 2005

AbstractA sensitive proton magnetic resonance spectroscopy (1H MRS) acquisition scheme that is capable of discriminating between normal controls and a group of patients with early Alzheimer's disease (AD) is presented. The performance of this newly developed method, TE averaged PRESS (PRESS‐J), in detecting neurodegeneration associated with early AD is compared with that of short echo time (TE) PRESS. A stepwise discriminant function analysis is used to construct discriminant functions for both pulse sequences. These functions are each composed of a single predictor: the N‐acetyl aspartate (NAA)/creatine (Cr) ratio for PRESS‐J, and the NAA/myoInositol (mI) ratio for PRESS. We observed lower P‐values, higher areas under the receiver operating characteristic curves, and higher sensitivity at a given specificity for the PRESS‐J discriminating function in comparison with the PRESS discriminating function. The higher sensitivity of PRESS‐J is due to decreased variability when the singlets are fit in the spectra. This increased sensitivity enables new MR applications and, among other benefits, allows for smaller group sizes in drug trials, which can significantly reduce the cost of such trials. Magn Reson Med 53:777–782, 2005. © 2005 Wiley‐Liss, Inc.
Open half‐volume quadrature transverse electromagnetic coil for high‐field magnetic resonance imaging
Authors: Peshkovsky A. S. , Kennan R. P. , Fabry M. E. , Avdievich N. I. 
Published: March 2005

AbstractA half‐volume quadrature head transverse electromagnetic (TEM) coil has been constructed for 4 T imaging applications. This coil produces a sufficiently large homogeneous B1 field region for the use as a volume coil. It provides superior transmission efficiency, resulting in significantly lower power deposition, as well as greater sensitivity and improved patient comfort and accessibility compared with conventional full‐volume coils. Additionally, this coil suppresses the RF penetration artifact that distorts the RF magnetic field profile and alters the intensity in high‐field images recorded with linear surface and volume coils. These advantages make it possible to apply this device as an efficient transmit/receive coil for high‐field imaging with a restricted field of view. Magn Reson Med 53:937–943, 2005. © 2005 Wiley‐Liss, Inc.
Fast, accurate, and automatic extraction of the modified talairach cortical landmarks from magnetic resonance images
Authors: Hu Qingmao , Qian Guoyu , Nowinski Wieslaw L. 
Published: March 2005

AbstractThe Talairach transformation is the most prevalent way to normalize brains and is hindered by, among others things, a lack of automatic determination of cortical landmarks. An algorithm to locate the modified Talairach cortical landmarks in three steps is proposed: determination of the three planes containing the landmarks; segmentation of the planes based on range‐constrained thresholding and morphologic operations; and local refinement of the segmentation to locate the landmarks. The algorithm has been validated against 62 T1‐weighted and SPGR MR diversified data sets. For each data set, it takes less than 2 s on a Pentium 4 to extract all six landmarks. The average landmark location errors are below 0.9 mm. The algorithm is robust due to incorporation of anatomic knowledge. A low computational cost results from processing of three 2D images and employing only simple operations like thresholding, basic morphologic operations, and distance transform. Magn Reson Med 53:970–976, 2005. © 2005 Wiley‐Liss, Inc.
Uncovering hidden in vivo resonances using editing based on localized TOCSY
Authors: Marjanska Malgorzata , Henry Pierre‐Gilles , Bolan Patrick J. , Vaughan Brooks , Seaquist Elizabeth R. , Gruetter Rolf , Uğurbil Kâmil , Garwood Michael 
Published: March 2005

AbstractA novel single‐shot spectral editing technique for in vivo proton NMR is proposed to recover resonances of low‐concentration metabolites obscured by very strong resonances. With this new method, editing is performed by transferring transverse magnetization to J‐coupled spins from selected coupling partners using a homonuclear Hartmann–Hahn polarization transfer with adiabatic pulses. The current implementation uses 1D‐TOCSY with single‐voxel localization based on LASER to recover the H1 proton of β‐glucose at 4.63 ppm from under water and the lactate methyl resonances from beneath a strong lipid signal. The method can be extended to further spin systems where conventional editing methods are difficult to perform. Magn Reson Med 53:783–789, 2005. © 2005 Wiley‐Liss, Inc.
Rotating‐frame intermolecular double‐quantum spin‐lattice relaxation T1ρ, DQC‐weighted magnetic resonance imaging
Authors: Zheng Bingwen , Hwang Dennis W. , Chen Zhong , Hwang Lian‐Pin 
Published: March 2005

AbstractIn this study, spin‐locking techniques were added as a part of intermolecular multiple‐quantum experiments, thereby introducing the concept of rotating‐frame intermolecular double‐quantum spin‐lattice relaxation, T1ρ, DQC. A novel magnetic resonance imaging methodology based on intermolecular multiple‐quantum coherences is demonstrated on a 7.05‐T microimaging scanner. The results clearly reveal that the intermolecular double‐quantum coherence T1ρ, DQC‐weighted imaging technique provides an alternative contrast mechanism to conventional imaging. Magn Reson Med 53:930–936, 2005. © 2005 Wiley‐Liss, Inc.
Contrast‐to‐noise ratios of diffusion anisotropy indices
Authors: Kingsley Peter B. , Monahan W. Gordon 
Published: March 2005

AbstractThe degree of diffusion anisotropy in different brain regions is usually measured by a diffusion anisotropy index (DAI) such as relative anisotropy (RA) and fractional anisotropy (FA). FA has been reported to have a higher contrast‐to‐noise ratio (CNR) than RA. The present work compares the CNRs of seven DAIs in theoretical propagation‐of‐error calculations, in simulations, and in human brain measurements over small and large anisotropy differences. In simulations all seven CNRs were similar for small anisotropy differences. Small differences among the DAIs appeared at higher anisotropy levels and lower signal‐to‐noise ratios with certain tensor orientations. The DAIs fell into three groups based on algebraic relationships and small CNR differences. The group with RA and FA had the best CNR. Human brain regions with small anisotropy differences had similar CNR for all seven DAIs, and the scatter in the data was greater than any expected differences. With large anisotropy differences, a small advantage appeared for RA over FA in some simulations and for FA over RA in other simulations. The CNR between brain regions with very different anisotropies was different for each DAI. The apparent reported advantage of FA over RA is explained by biologic heterogeneity and by noise‐induced bias in the DAI values and their standard deviations. Magn Reson Med 53:911–918, 2005. © 2005 Wiley‐Liss, Inc.
Visualization of cortical spreading depression using manganese‐enhanced magnetic resonance imaging
Authors: Henning Erica C. , Meng Xiangjun , Fisher Marc , Sotak Christopher H. 
Published: March 2005

AbstractCortical spreading depression (CSD) was visualized using manganese‐enhanced MRI (MEMRI) following topical application of KCl to the exposed rat cortex. MEMRI signal increase in the ipsilateral cortex relative to the contralateral control region was 60 ± 30% following two KCl applications. MEMRI signal increase for a single (40%) versus double (80%) KCl application suggests an integration effect over successive CSD episodes. CSD‐induced MEMRI enhancement involved cortical layers containing dense regions of apical dendrites, supporting the contention that these neuronal structures are necessary for propagation of CSDs. Subcortical enhancement was present in hippocampal and thalamic regions, most likely a result of neuronal connections with cortical layers 4 and 5. These results are consistent with previous studies of CSD using diffusion‐weighted MRI and T2*‐weighted MRI and should be useful for investigating CSD itself and its role in other neurologic disorders. Magn Reson Med 53:851–857, 2005. © 2005 Wiley‐Liss, Inc.
Iopamidol: Exploring the potential use of a well‐established x‐ray contrast agent for MRI
Authors: Aime Silvio , Calabi Luisella , Biondi Luca , De Miranda Mario , Ghelli Stefano , Paleari Lino , Rebaudengo Cristina , Terreno Enzo 
Published: March 2005

AbstractIopamidol is one of the most common contrast media used for diagnostic CT‐based clinical protocols. Chemically, this molecule contains two pools of mobile protons (amide and alcoholic) that are in exchange with water. At 7.05 T, pH 7.4, and 312 K, the exchange rate of the alcoholic protons is too fast to affect the NMR properties of water protons, whereas the slowly exchanging amide protons induce a T2‐shortening effect on the “bulk” water signal that is detectable when the concentration is about 12 mM. Moreover, a more pronounced contrast is observed when the amide resonances are saturated by the application of an appropriate RF irradiation field, making iopamidol a potential chemical exchange saturation transfer (CEST) agent whose effect can be detected at a concentration as low as 7 mM (at 7.05 T). The exploitation of the MRI properties of iopamidol could facilitate novel and interesting diagnostic applications for combined MRI and CT studies. Magn Reson Med 53:830–834, 2005. © 2005 Wiley‐Liss, Inc.
Short breath‐hold, volumetric coronary MR angiography employing steady‐state free precession in conjunction with parallel imaging
Authors: Niendorf Thoralf , Saranathan Manojkumar , Lingamneni Anila , Pedrosa Ivan , Spencer Matthew , Cline Harvey , Foo Thomas K.F. , Rofsky Neil M. 
Published: March 2005

AbstractAn ECG‐gated, 3D steady‐state free precession (SSFP) technique in conjunction with sensitivity encoding (SENSE)‐based parallel imaging was implemented for short breath‐hold, volumetric coronary MR angiograpy (CMRA). Two parallel imaging acquisition strategies (employing 1 R‐R and 2 R‐R intervals, respectively) were developed to achieve 1) very short breath‐hold times (12 s for a heart rate of 60 bpm), and 2) small acquisition windows to minimize sensitivity to physiologic motion. Both strategies were examined in CMRA applications over a range of heart rates. A four‐point scale blinded reading (with 4 indicating the most desirable features) revealed substantial image quality improvements for the accelerated data as compared to the nonaccelerated approach. The 1 R‐R interval scheme yielded an image score of 3.39 ± 0.60, and was found to be particularly suitable for low heart rates (P = 0.0008). The 2 R‐R interval strategy yielded an image score of 3.35 ± 0.64, and was more appropriate for higher heart rates (P = 0.03). The results demonstrate that 3D SSFP combined with parallel imaging is a versatile method for short breath‐hold CMRA while maintaining high spatial resolution. This strategy permits imaging of the major coronary artery distributions in two to three breath‐holds using targeted slabs, and offers the potential for single breath‐hold, large‐volume CMRA. Magn Reson Med 53:885–894, 2005. © 2005 Wiley‐Liss, Inc.
3He lung imaging in an open access, very‐low‐field human magnetic resonance imaging system
Authors: Mair R. W. , Hrovat M. I. , Patz S. , Rosen M. S. , Ruset I. C. , Topulos G. P. , Tsai L. L. , Butler J. P. , Hersman F. W. , Walsworth R. L. 
Published: March 2005

AbstractThe human lung and its functions are extremely sensitive to gravity; however, the conventional high‐field magnets used for most laser‐polarized 3He MRI of the human lung restrict subjects to lying horizontally. Imaging of human lungs using inhaled laser‐polarized 3He gas is demonstrated in an open‐access very‐low‐magnetic‐field (<5 mT) MRI instrument. This prototype device employs a simple, low‐cost electromagnet, with an open geometry that allows variation of the orientation of the imaging subject in a two‐dimensional plane. As a demonstration, two‐dimensional lung images were acquired with 4‐mm in‐plane resolution from a subject in two orientations: lying supine and sitting in a vertical position with one arm raised. Experience with this prototype device will guide optimization of a second‐generation very‐low‐field imager to enable studies of human pulmonary physiology as a function of subject orientation. Magn Reson Med 53:745–749, 2005. © 2005 Wiley‐Liss, Inc.
Analysis of a new BEM‐FEM coupling for two‐dimensional fluid‐solid interaction
Authors: Meddahi Salim , Sayas Francisco‐Javier 
Published: March 2005

AbstractIn this work we present a new numerical method, based on a coupling of finite and boundary elements, to solve a fluid‐solid interaction problem in the plane. The discrete method uses classical Lagrange finite elements adapted to curved boundaries for the field variable and spectral approximation of the unknowns on the artificial boundary. We provide error estimates for this Galerkin scheme and propose a full discretization based on elementary quadrature formulae, showing that the perturbation due to numerical integration preserves the optimal rate of convergence. We also suggest an iterative method to solve the complicated linear systems arising from this type of schemes. © 2005 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2005
A mixed nonconforming finite element for linear elasticity
Authors: Cai Zhiqiang , Ye Xiu 
Published: March 2005

AbstractThis article considers a mixed finite element method for linear elasticity. It is based on a modified mixed formulation that enforces the continuity of the stress weakly by adding a jump term of the approximated stress on interior edges. The symmetric stress are approximated by nonconforming linear elements and the displacement by piecewise constants. We establish 𝒪(h) error bound in the (broken) L2 norm for the divergence of the stress and 𝒪(h) error bound in the L2 norm for both the displacement and the stress tensor. © 2005 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2005.
Role of afterload reduction in the prevention of late anthracycline cardiomyopathy
Authors: Silber Jeffrey H. 
Published: March 2005

AbstractAfterload reduction is useful for treating and preventing adult congestive heart failure outside the realm of anthracycline toxicity. Afterload reducers are commonly used as treatment for acute heart failure associated with anthracyclines. However, the use of afterload reduction for the prevention of anthracycline associated late cardiomyopathy remains a controversial area, with strong opinions expressed concerning the potential risks and benefits of such an approach. This article will define “afterload” and the tools utilized to measure afterload. The study will then describe the theory for the use of afterload reduction in patients with anthracycline exposure who show signs of anthracycline cardiotoxicity, and will present data from the ACE‐Inhibitor After Anthracyclines (AAA) Trial to help answer the question, “Should an afterload reducer be used to aid in preventing late anthracycline cardiotoxicity?” Finally, recommendations for future research will be presented. Pediatr Blood Cancer 2005;44:607–613. © 2005 Wiley‐Liss, Inc.
Clinical and molecular characteristics of pediatric gastrointestinal stromal tumors (GISTs)
Authors: Price Victoria E. , Zielenska Maria , Chilton‐MacNeill Susan , Smith Charles. R. , Pappo Alberto S. 
Published: March 2005

AbstractBackgroundTo describe the clinical characteristics, molecular features, treatment, and outcome of six pediatric patients with gastrointestinal stromal tumors (GISTs).Patients and MethodsRetrospective clinical review of GISTs, seen at The Hospital for Sick Children (HSC) Toronto, over an 11‐year period. All specimens were stained for the CD 117 and CD 34 antigens. Three specimens were sequenced for mutations in exons 9, 11, and 13 of the c‐kit gene.ResultsFive patients were evaluated and treated at HSC and one was referred for histopathological consultation only. The median patient age at diagnosis was 13.6 years, (6.9–14.8 years); four were female. All patients presented with anemia secondary to gastrointestinal (GI) bleeding. The disease was localized in five patients and two had other malignancies consistent with the diagnoses of Carney's triad. Immunohistochemical staining for CD 117 and CD 34 showed heavy cytoplasmic localization in all of the tumor cells. A novel point mutation of KIT in codon 456 of exon 9 was found in one case. Complete surgical resection was achieved in the five patients managed at our center and none received adjuvant therapies. Disease recurred locally in one patient. Four patients are alive and one is lost to follow‐up.ConclusionsIn children and adolescents, GISTs should be considered in the differential diagnosis of anemia secondary to GI hemorrhage. The absence of an exon 11 mutation and the identification of a novel mutation in exon 9 suggest that pediatric GISTs may respond differently to currently available targeted therapies and therefore should be studied within the context of collaborative group trials. Pediatr Blood Cancer 2005; 45:20–24. © 2005 Wiley‐Liss, Inc.