bluuebunny/crossref_metadata_2025_split huggingface dataset:
Magnetic resonance imaging evaluation of renal structure and function related to disease: Technical review of image acquisition, postprocessing, and mathematical modeling steps
Authors: Jones Richard A. , Votaw John R. , Salman Khalil , Sharma Puneet , Lurie C. , Kalb Bobby , Martin Diego R. 
Published: May 2011

AbstractKidney disease represents a leading cause of morbidity, with high healthcare costs. The existing methods used to evaluate renal function include measures of glomerular filtration rate (GFR), yet the clinical methods are generally inaccurate and poorly reproducible. A method that improves measures of renal function as part of a comprehensive examination that also evaluates renal structure represents an important unmet clinical need. Use of dynamic contrast‐enhanced magnetic resonance imaging (MRI) for the evaluation of renal function has been undergoing development by several groups. The methodology has been referred to as MR Urography (MRU) or MR Nephro‐urography (MRNU). MRU/MRNU shows promise for providing new insights into the evaluation of renal structure and function in relation to important disease processes, including urinary obstruction and in relation to renal transplantation. MRU/MRNU generally requires consideration of imaging acquisition technique, image postprocessing strategies, and subsequent kinetic mathematical modeling of the data in reference to specific physiological renal processes, such as renal blood flow and GFR. Here we review the specifics of proposed methods in light of the overall strengths and limitations of each of these strategies. The overall objective is to provide a roadmap for future developments in this evolving field of novel MRI applications. J. Magn. Reson. Imaging 2011;33:1270–1283. © 2011 Wiley‐Liss, Inc.
MR elastography of human lung parenchyma: Technical development, theoretical modeling and in vivo validation
Authors: Mariappan Yogesh K. , Glaser Kevin J. , Hubmayr Rolf D. , Manduca Armando , Ehman Richard L. , McGee Kiaran P. 
Published: May 2011

AbstractPurpose:To develop a novel MR‐based method for visualizing the elastic properties of human lung parenchyma in vivo and to evaluate the ability of this method to resolve differences in parenchymal stiffness at different respiration states in healthy volunteers.Materials and Methods:A spin‐echo MR Elastography (MRE) pulse sequence was developed to provide both high shear wave motion sensitivity and short TE for improved visualization of lung parenchyma. The improved motion sensitivity of this approach was modeled and tested with phantom experiments. In vivo testing was then performed on 10 healthy volunteers at the respiratory states of residual volume (RV) and total lung capacity (TLC).Results:Shear wave propagation was visualized within the lungs of all volunteers and was processed to provide parenchymal shear stiffness maps for all 10 subjects. Density corrected stiffness values at TLC (1.83 ± 0.22 kPa) were higher than those at the RV (1.14 ± 0.14 kPa) with the difference being statistically significant (P < 0.0001).Conclusion:1H‐based MR elastography can noninvasively measure the shear stiffness of human lung parenchyma in vivo and can quantitate the change in shear stiffness due to respiration. The values obtained were consistent with previously reported in vitro assessments of cadaver lungs. Further work is required to increase the flexibility of the current acquisition and to investigate the clinical potential of lung MRE. J. Magn. Reson. Imaging 2011;33:1351–1361. © 2011 Wiley‐Liss, Inc.
Targeted single‐shot methods for diffusion‐weighted imaging in the kidneys
Authors: Jin Ning , Deng Jie , Zhang Longjiang , Zhang Zhuoli , Lu Guangming , Omary Reed A. , Larson Andrew C. 
Published: May 2011

AbstractPurpose:To investigate the feasibility of combining the inner‐volume‐imaging (IVI) technique with single‐shot diffusion‐weighted (DW) spin‐echo echo‐planar imaging (SE‐EPI) and DW‐SPLICE (split acquisition of fast spin‐echo) sequences for renal DW imaging.Materials and Methods:Renal DWI was performed in 10 healthy volunteers using single‐shot DW‐SE‐EPI, DW‐SPLICE, targeted‐DW‐SE‐EPI, and targeted‐DW‐SPLICE. We compared the quantitative diffusion measurement accuracy and image quality of these targeted‐DW‐SE‐EPI and targeted DW‐SPLICE methods with conventional full field of view (FOV) DW‐SE‐EPI and DW‐SPLICE measurements in phantoms and normal volunteers.Results:Compared with full FOV DW‐SE‐EPI and DW‐SPLICE methods, targeted‐DW‐SE‐EPI and targeted‐DW‐SPLICE approaches produced images of superior overall quality with fewer artifacts, less distortion, and reduced spatial blurring in both phantom and volunteer studies. The apparent diffusion coefficient (ADC) values measured with each of the four methods were similar and in agreement with previously published data. There were no statistically significant differences between the ADC values and intravoxel incoherent motion (IVIM) measurements in the kidney cortex and medulla using single‐shot DW‐SE‐EPI, targeted‐DW‐EPI, and targeted‐DW‐SPLICE (P > 0.05).Conclusion:Compared with full‐FOV DWI methods, targeted‐DW‐SE‐EPI and targeted‐DW‐SPLICE techniques reduced image distortion and artifacts observed in the single‐shot DW‐SE‐EPI images, reduced blurring in DW‐SPLICE images, and produced comparable quantitative DW and IVIM measurements to those produced with conventional full‐FOV approaches. J. Magn. Reson. Imaging 2011;33:1517–1525. © 2011 Wiley‐Liss, Inc.
Detection of early response to temozolomide treatment in brain tumors using hyperpolarized 13C MR metabolic imaging
Authors: Park Ilwoo , Bok Robert , Ozawa Tomoko , Phillips Joanna J. , James C. David , Vigneron Daniel B. , Ronen Sabrina M. , Nelson Sarah J. 
Published: May 2011

AbstractPurpose:To demonstrate the feasibility of using DNP hyperpolarized [1‐13C]‐pyruvate to measure early response to temozolomide (TMZ) therapy using an orthotopic human glioblastoma xenograft model.Materials and Methods:Twenty athymic rats with intracranial implantation of human glioblastoma cells were divided into two groups: one group received an oral administration of 100 mg/kg TMZ (n = 10) and the control group received vehicle only (n = 10). 13C 3D magnetic resonance spectroscopic imaging (MRSI) data were acquired following injection of 2.5 mL (100 mM) hyperpolarized [1‐13C]‐pyruvate using a 3T scanner prior to treatment (day D0), at D1 (days from treatment) or D2.Results:Tumor metabolism as assessed by the ratio of lactate to pyruvate (Lac/Pyr) was significantly altered at D1 for the TMZ‐treated group but tumor volume did not show a reduction until D5 to D7. The percent change in Lac/Pyr from baseline was statistically different between the two groups at D1 and D2 (P < 0.008), while percent tumor volume was not (P > 0.2).Conclusion:The results from this study suggest that metabolic imaging with hyperpolarized [1‐13C]‐pyruvate may provide a unique tool that clinical neuro‐oncologists can use in the future to monitor tumor response to therapy for patients with brain tumors. J. Magn. Reson. Imaging 2011;33:1284–1290. © 2011 Wiley‐Liss, Inc.
Vascular staging of renal and adrenal malignancies with a noncontrast enhanced steady state free precession technique
Authors: Lee Christine U. , Glockner James F. 
Published: May 2011

AbstractPurpose:To compare a noncontrast enhanced balanced steady state free precession (bSSFP) MRI technique with a conventional dynamic contrast‐enhanced (DCE) three‐dimensional (3D) spoiled gradient recalled echo (SPGR) imaging in the vascular staging of renal and adrenal malignancies.Materials and Methods:Sixty‐three MRIs with both bSSFP and DCE acquisitions performed for initial staging of renal and adrenal malignancies were retrospectively evaluated for presence and extent of thrombus in the renal veins and inferior vena cava (IVC). Thrombus characterization was also evaluated. DCE imaging was used as the standard‐of‐reference. Histopathology was available in 46 of 63 cases as an additional external standard.Results:There is very good agreement between bSSFP and DCE imaging for determining the presence or absence of thrombus in the renal veins (r = 0.95; P < 0.0001) and IVC (r = 0.91; P < 0.0001). BSSFP is less successful at distinguishing bland from tumor thrombus.Conclusion:Noncontrast enhanced bSSFP is an acceptable alternative to DCE imaging for vascular staging of locally advanced renal/adrenal malignancies, with somewhat limited ability to distinguish bland from tumor thrombus. J. Magn. Reson. Imaging 2011;33:1406–1413. © 2011 Wiley‐Liss, Inc.
Practical signal‐to‐noise ratio quantification for sensitivity encoding: Application to coronary MR angiography
Authors: Yu Jing , Agarwal Harsh , Stuber Matthias , Schär Michael 
Published: May 2011

AbstractPurpose:To develop and evaluate a practical method for the quantification of signal‐to‐noise ratio (SNR) on coronary MR angiograms (MRA) acquired with parallel imaging.Materials and Methods:To quantify the spatially varying noise due to parallel imaging reconstruction, a new method has been implemented incorporating image data acquisition followed by a fast noise scan during which radiofrequency pulses, cardiac triggering and navigator gating are disabled. The performance of this method was evaluated in a phantom study where SNR measurements were compared with those of a reference standard (multiple repetitions). Subsequently, SNR of myocardium and posterior skeletal muscle was determined on in vivo human coronary MRA.Results:In a phantom, the SNR measured using the proposed method deviated less than 10.1% from the reference method for small geometry factors (≤2). In vivo, the noise scan for a 10 min coronary MRA acquisition was acquired in 30 s. Higher signal and lower SNR, due to spatially varying noise, were found in myocardium compared with posterior skeletal muscle.Conclusion:SNR quantification based on a fast noise scan is a validated and easy‐to‐use method when applied to three‐dimensional coronary MRA obtained with parallel imaging as long as the geometry factor remains low. J. Magn. Reson. Imaging 2011;33:1330–1340. © 2011 Wiley‐Liss, Inc.
Preclinical use of longitudinal MRI for screening the efficacy of s‐nitrosoglutathione in treating spinal cord injury
Authors: Chou Peter Cheng‐te , Shunmugavel Anandakumar , Sayed Hanaa El , Desouki Mohamed Mokhtar , Nguyen Shaun A. , Khan Mushfiquddin , Singh Inderjit , Bilgen Mehmet 
Published: May 2011

AbstractPurpose:To evaluate the therapeutic efficacy of S‐nitrosoglutathione (GSNO) in spinal cord injury (SCI) using in vivo MRI in combination with neuorobehavioral testing and postmortem tissue analysis.Materials and Methods:Sixteen female rats were mildly injured at the vertebral T10 level and randomized into control (n = 8) and GSNO‐treatment (n = 8) groups. GSNO was delivered at 0.05 mg/kg dose in saline by means of tail vein at 1 hr postinjury and then given orally on the following days. On postinjury days 1, 3, 7, and 28, the rats were tested behaviorally, then scanned using sagittal T2‐weighted MRI for the quantification of lesion, edema, and hemorrhagic regions at the injury site. Excised cords were analyzed using histology and immunohistochemistry.Results:Treatment with GSNO was feasible in rats with SCI. On the average, the GSNO group at each scan day 1, 3, 7, and 28 exhibited better functional recovery as indicated by the behavioral performance of 52%, 33%, 19%, and 18%, and had smaller lesions of −4%, −16%, −20%, and −17% compared with the controls, respectively. Edema trend was parallel to the lesion volumes in both groups. Ex vivo data demonstrated that GSNO plays a role in neuronal tissue preservation and sparing.Conclusion:The data collectively provided the preliminary evidence that the injured rats responded favorably to GSNO treatment. Longitudinal MRI provides critical quantitative information regarding the changes in lesion properties, which helps evaluating the efficacy of an exogenous intervention in SCI. J. Magn. Reson. Imaging 2011;33:1301–1311. © 2011 Wiley‐Liss, Inc.
Comparative study of standard space and real space analysis of quantitative MR brain data
Authors: Aribisala Benjamin S. , He Jiabao , Blamire Andrew M. 
Published: May 2011

AbstractPurpose:To compare the robustness of region of interest (ROI) analysis of magnetic resonance imaging (MRI) brain data in real space with analysis in standard space and to test the hypothesis that standard space image analysis introduces more partial volume effect errors compared to analysis of the same dataset in real space.Materials and Methods:Twenty healthy adults with no history or evidence of neurological diseases were recruited; high‐resolution T1‐weighted, quantitative T1, and B0 field‐map measurements were collected. Algorithms were implemented to perform analysis in real and standard space and used to apply a simple standard ROI template to quantitative T1 datasets. Regional relaxation values and histograms for both gray and white matter tissues classes were then extracted and compared.Results:Regional mean T1 values for both gray and white matter were significantly lower using real space compared to standard space analysis. Additionally, regional T1 histograms were more compact in real space, with smaller right‐sided tails indicating lower partial volume errors compared to standard space analysis.Conclusion:Standard space analysis of quantitative MRI brain data introduces more partial volume effect errors biasing the analysis of quantitative data compared to analysis of the same dataset in real space. J. Magn. Reson. Imaging 2011;33:1503–1509. © 2011 Wiley‐Liss, Inc.
Impact of outliers on diffusion tensor and Q‐ball imaging: Clinical implications and correction strategies
Authors: Sharman Michael A. , Cohen‐Adad Julien , Descoteaux Maxime , Messé Arnaud , Benali Habib , Lehericy Stéphane 
Published: May 2011

AbstractPurpose:To measure the impact of corrupted images often found to occur in diffusion‐weighted magnetic resonance imaging (DW‐MRI). To propose a robust method for the correction of outliers, applicable to diffusion tensor imaging (DTI) and q‐ball imaging (QBI).Materials and Methods:Monte Carlo simulations were carried out to measure the impact of outliers on DTI and QBI reconstruction in a single voxel. Methods to correct outliers based on q‐space interpolation and direction removal were then implemented and validated in real image data.Results:Corruption in a single voxel led to clear variations in DTI and QBI metrics. In real data, the method of q‐space interpolation was successful in identifying corrupted voxels and restoring them to values consistent with those of uncorrupted images.Conclusion:For images containing few gradient directions, where outlier removal was either impossible due to limited volumes or resulted in large changes in DTI/QBI metrics, q‐space interpolation proved to be the method of choice for image restoration. A simple decision support system is proposed to assist clinicians in the correction of their corrupted DW data. J. Magn. Reson. Imaging 2011;33:1491–1502. © 2011 Wiley‐Liss, Inc.
Synoptic environments favourable for urban convection in Atlanta, Georgia
Authors: Bentley Mace L. , Stallins J. Anthony , Ashley Walker S. 
Published: May 2011

AbstractAn examination of synoptic environments conducive to urban thunderstorm development surrounding Atlanta, Georgia, was conducted. Synoptic environmental characteristics were evaluated utilising regional analyses of heights, winds, temperature, and moisture characteristics as well as several thermodynamic variables. A flexible beta cluster analysis was used in order to identify disparate groupings of common synoptic and thermodynamic environments. These groupings were then further analysed through the production of synoptic composites, radar, and lightning distributions. Although the analysis stratified the data by days with weak synoptic flow and maritime tropical airmass characteristics, enough variation existed within the synoptic and thermodynamically grouped parameters to identify four distinct environments present during urban thunderstorms. Environments exhibiting moderate thermodynamic instability were found to produce the highest flash rates and most frequent composite reflectivity days. Copyright © 2011 Royal Meteorological Society
Quasi‐quadrennial variability in European precipitation
Authors: Álvarez‐García Francisco J. , Lorente‐Lorente Pilar M. , OrtizBevia María J. 
Published: May 2011

AbstractThe variability of seasonal precipitation anomalies over Europe displays significant spectral peaks at quasi‐quadrennial periods, appearing in power spectra of the two leading principal components of the field. Band‐pass filtering of these time series reveals the presence of two different signals within the quadrennial band, each associated to distinct precipitation, sea level pressure (SLP) and sea surface temperature (SST) patterns, obtained here by means of linear regression and composite analysis. One of the quadrennial components seems to be connected with the impact of El Niño‐Southern Oscillation (ENSO) over Europe, that leads to anomalous SLP over the North Sea, southwestern Scandinavia and central Europe, along with precipitation anomalies of the same sign in a wide band extending from the British Isles into eastern Europe, fringed by anomalies of the opposite sign along the Norwegian coast and in the western Mediterranean area. The other quadrennial component bears no correlation with the Tropical Pacific SST anomalies, and seems connected with SST anomalies in the equatorial Atlantic, and in the Mediterranean, North and Norwegian Seas. The precipitation anomalies feature a contrast between the northern and southern regions of Europe akin to that associated with the North Atlantic Oscillation (NAO). The SLP pattern resembles the NAO structure, but with a marked eastward shift of its two centres of action towards central Europe and the Barents Sea, respectively. Copyright © 2011 Royal Meteorological Society
Decadal variability in springtime snow over Eurasia: Relation with circulation and possible influence on springtime rainfall over China
Authors: Zuo Zhiyan , Zhang Renhe , Wu Bingyi , Rong Xinyao 
Published: May 2011

AbstractThe relationship between decadal variability in springtime (March–May) snow water equivalent (SWE) over Eurasia and springtime rainfall over China is investigated for 1979–2004 using satellite‐observed SWE, rainfall observations from 595 stations, and NCEP/NCAR reanalysis data. Decreasing springtime SWE in Eurasia corresponded to reduced springtime rainfall over southeastern and northeast China, and more rainfall over southwestern and northwestern China. This relationship was supported by the feedback effect of snow in high‐latitude areas to changes in background atmospheric circulation.A decadal shift in springtime Eurasian SWE occurred in the late 1980s, marked by a change from persistent positive phases in 1979–1987 to frequent negative phases. The reduction in Eurasian SWE resulted in reduced upward surface heat flux to the atmosphere and, thereby, higher boundary layer height due to increased downward heat flux into subsurface soil. These changes resulted in reduced upward and poleward wave flux activity, which corresponded to anomalous negative heights/pressures in the Arctic and anomalous positive heights/pressures in mid‐latitude regions from the upper‐level troposphere to the surface. There was an anomalous anti‐cyclonic circulation over Siberia and the western Pacific subtropical high was weakened, accompanied by an anomalous northerly in eastern China and westerly in northwestern China. The anomalous northerly resulted in reduced water vapour convergence in southeastern and northeast China, and reduced water vapour export for southwestern and northwestern China. Thus, negative rainfall anomalies developed over southeastern and northeast China, and positive rainfall anomalies appeared over southwestern and northwestern China. Copyright © 2011 Royal Meteorological Society
Late 20th‐century trends in Iowa watersheds: an investigation of observed and modelled hydrologic storages and fluxes in heavily managed landscapes
Authors: Steffens Kayla J. , Franz K. J. 
Published: May 2011

AbstractMany climate change studies have shown that streamflow has been changing across the US over the last century. However, there are fewer studies examining trends in hydrologic variables such as soil moisture and snow, which tend to be poorly observed in some regions. Hydrologic models can be applied to understand changes in processes with limited spatial or temporal observational records. However, the application of hydrologic models to long time periods can be complicated by human influences on the hydrologic cycle. In this study, we explore hydrologic changes and the applicability of a commonly used hydrologic modelling system for climate change analysis in a heavily managed landscape. Historical streamflow observations and model‐derived time series of subsurface storage, frozen ground, and snow cover were analysed for 10 Iowa watersheds. The modelled data were generated using precipitation and temperature data spanning 1948–2003 as inputs to common hydrologic prediction models. Time series were tested for trends and significance using the Mann‐Kendall (MK) test with the Trend‐Free Pre‐Whitening procedure at a p = 0.1 significance level. Plots of 10‐year running averages were also examined. Significantly increasing trends in mean daily discharge and the number of high‐flow days were found for several watersheds. Increasing monthly subsurface water content was observed throughout the year in most basins, and was greatest during the winter. The number of modelled frozen‐ground days declined at all sites. Three different model calibration periods were tested and found to reproduce the general upward trend observed in the daily mean discharge. However, the model results varied from the observed in both magnitude and the number of sites identified to have MK trends. Additional functionality that considers land management and land cover change may make the models applied here more accurate for studying climate change impacts in regions such as Iowa. Copyright © 2011 Royal Meteorological Society
Synthesis and Characterization of Cytocompatible Sulfonated Polyanilines
Authors: Yang Yanyin , Min Yong , Wu Jen‐Chieh , Hansford Derek J. , Feinberg Stephen E. , Epstein Arthur J. 
Published: May 2011

AbstractWe report here that by good design, polyaniline (PANI) can be cytocompatible and formed into usable scaffolds for bio‐medical applications. By adjusting the ratio of two monomers, aniline (AN) and metanilic acid (MA), a series of copolymers with different sulfonation degrees have been synthesized. Four‐probe conductivity measurements showed that as the sulfonation degree increased, the conductivity decreased. XPS analysis was used to determine the sulfur/nitrogen ratio. In vitro cell culture study was conducted with human osteosarcoma (HOS) cells. Microscopic observation did not show abnormal cellular behavior when sulfonated polyaniline (SPAN) was put in direct contact with HOS cells. Cells growing on the non‐transparent dark green SPAN films were observed with fluorescence by laser scanning cytometry (LSC). In proliferation studies more than 70% of cells were found viable on SPAN compared to 88% for poly(L‐lactic acid) with the number of cells growing on glass as a control, indicating generally good biocompatibility. We expect these polymers would have great potential in biological applications of conducting polymers as we determine that a variety of physical and chemical properties can be controlled through synthesis. magnified image