bluuebunny/crossref_metadata_2025_split huggingface dataset:
Climate change impacts on groundwater temperature change in the Sendai plain, Japan
Authors: Gunawardhana Luminda Niroshana , Kazama So 
Published: January 2011

AbstractGroundwater temperature is a key parameter regulating the ecological balance of the ecosystems in groundwater dominated wetlands, estuaries and ponds. This study evaluated the potential impacts of climate change on groundwater temperature and proposed a methodology for use in areas with limited hydrological and metrological data. Groundwater temperatures were measured in 1 m intervals in five observation wells and used for groundwater recharge estimation. Three different techniques, the water balance method, the water level fluctuation (WLF) method and Darcy's method, were performed to verify the estimated recharge rates from the temperature‐depth profiles. Of the six sets of global climate model (GCM) predictions analysed, three of them were selected by considering a range of potential climate changes in the future. The transfer function method was used to downscale the GCM outputs of precipitation and temperature of the Sendai plain. Raw GCM data for nine scenarios (A2, A1B, and B1 from HADCM3, MRI, and ECHAM5 models) and observed data from 1967 to 2006 were used to develop the transfer functions. Derived functions, which were tested for 1927–1966, were used to downscale GCM data for 2060–2099. These predictions were used in a one‐dimensional heat transport model, which was calibrated to the existing site conditions by the water budget technique. There are marked differences among the scenarios and GCMs. However, all the model scenarios projected increasing trends in temperature and precipitation for the 2060–2099 time period. HADCM3 A2 scenario shows the strongest effect compared with the base line climate (1967–2006), which involves an increase in the air temperature of 3·9 °C and an increase in annual precipitation of 345 mm. When considering all GCM scenarios compared with observations in 2006, the aquifer temperature at 8 m depth from the ground surface could possibly increase within the range of 1·2–3·3 °C by 2080. The above findings from the methodology developed here will be important for estimating the impact of climate change and will be useful for environmental management programs. Copyright © 2011 John Wiley & Sons, Ltd.
Influence of freshwater input and bay reclamation on long‐term changes in seawater residence times in Tokyo bay, Japan
Authors: Okada Tomonari , Nakayama Keisuke , Takao Toshiyuki , Furukawa Keita 
Published: January 2011

AbstractIn this study, we demonstrated that the residence time of seawater in Tokyo bay, Japan, has changed over time because of fresh water imported from neighbouring catchments and reclamation of portions of the bay. The residence time of seawater was estimated from data collected in 2002, and compared with re‐estimates of the residence time based on data from 1947 to 1974. We also used a numerical model to examine the effects of changes in the freshwater input and in the surface area of the bay on the seawater residence time. Our analysis showed that the seawater residence time decreased by 35% from the period prior to 2002. The effects of the increase in freshwater input and the decrease in the sea surface area over this period on the decrease in residence time were almost the same. Eighty percent of the increase in freshwater input resulted from water imported from neighbouring catchment areas. In terms of the relationship between seawater residence time and water quality, the effects of the imported fresh water were almost the same as those of bay reclamation. Copyright © 2011 John Wiley & Sons, Ltd.
Cyclooctatetraene dianion—an artifact?
Authors: Dominikowska Justyna , Palusiak Marcin 
Published: January 2011

AbstractCyclooctatetraene in its dianionic form (COT2−) is considered to be partially or fully aromatic due to the fact that, unlike its neutral counterpart, it adopts planar structure with CC bonds equalized. However, some authors report that this dianion is neither planar nor aromatic. Thus, we performed a detailed analysis of the COT2− case. The influence of several technical parameters on the result of calculations on COT2− was investigated. It appears from our analysis that the use of some specific level of approximation may lead to very misleading results in which the COT ring occurs in its neutral structure, in fact being neither planar nor aromatic. Additionally, our results may suggest that COT2− dianion is rather an artificial structure (being the result of specific basis set description) and should not occur in experimental conditions. © 2011 Wiley Periodicals, Inc. J Comput Chem, 2011
Development of a wide‐view visual presentation system for visual retinotopic mapping during functional MRI
Authors: Yan Tianyi , Jin Fengzhe , He Jiping , Wu Jinglong 
Published: January 2011

AbstractPurposeTo develop and validate the functionality of a novel wide‐view visual presentation system with a horizontal and vertical eccentricity angle of 60° for retinotopic mapping by functional MRI (fMRI).Materials and MethodsThe wide‐view presentation system consisted of a 52‐mm diameter optical fiber, an entrance apparatus and a presentation apparatus. The terminal edge of the optical fiber at the entrance is flat, while the terminal edge on the presentation apparatus is a sphere of 60 mm in diameter. The subjects wore contact lenses with +20, +22, or +25 magnification to focus on the stimulus, and the visual field eccentricity angle could reach 60°. The signal to noise ratio valuation experiment was performed to evaluate the clarity and quality of the MRI picture image. Checkerboard and random dot stimuli were used to prove that this system could be applied to retinotopic mapping by fMRI.ResultsThe results of the experiment demonstrated that the system is safe in the MRI environment with minimal distortion and can be used for visual retinotopic mapping studies. Wide‐field mapping areas (V6, MST) were found in the human visual cortex. Compared with previous studies, the V1 and MT+ surface area approaches but does not fully cover the anatomical area. Nonetheless, the area achieved using the new system is larger than those achievable in previous fMRI studies.ConclusionWe developed a versatile, low‐cost system for presenting wide‐view visual stimuli in the MRI environment. The fMRI retinotopic mapping results proved the viability of this system. J. Magn. Reson. Imaging 2011. © 2011 Wiley‐Liss, Inc.
MRI of the prostate: Clinical relevance and emerging applications
Authors: Mazaheri Yousef , Shukla‐Dave Amita , Muellner Ada , Hricak Hedvig 
Published: January 2011

AbstractMRI of the prostate can aid in many aspects of prostate cancer management, from initial detection to treatment planning and follow‐up. This review describes the current strengths and limitations of conventional anatomic and molecular MR imaging techniques (including MR spectroscopic imaging and dynamic contrast‐enhanced imaging) for aiding prostate cancer management. It also describes promising emerging approaches for acquiring, analyzing, and applying MR imaging data, and the major research and educational efforts that will be required to realize the potential of prostate MR imaging in routine clinical practice. J. Magn. Reson. Imaging 2011;33:258–274. © 2011 Wiley‐Liss, Inc.
Diffusion MRI predicts transrectal ultrasound biopsy results in prostate cancer detection
Authors: Chen Yu‐Jen , Pu Yeong‐Shiau , Chueh Shih‐Chieh , Shun Chia‐Tung , Chu Woei‐Chyn , Tseng Wen‐Yih Isaac 
Published: January 2011

AbstractPurposeTo evaluate the ability of diffusion tensor imaging (DTI) to predict the transrectal ultrasound (TRUS) biopsy outcomes in persons who have no history of previous TRUS biopsy and present with elevated prostate‐specific antigen (PSA) levels.Materials and MethodsThirty‐seven participants underwent DTI, followed by 12‐core TRUS‐guided needle biopsy within 2 weeks. DTI was performed using endorectal coils on a 1.5 Tesla scanner at 1‐mm3 spatial resolution. By comparing with the TRUS biopsy results, the optimum thresholds of the trace apparent diffusion coefficient (tADC) and of the nodular size were investigated. The diagnostic performance of both criteria, the tADC threshold (Criteria A) and the tADC threshold combined with nodular size threshold (Criteria B), were evaluated.ResultsThe optimum tADC threshold was 1.0 μm2/ms. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of prostate cancer (PCA) detection for Criteria A were 98%, 89%, 73%, 99%, and 91%, respectively, and were 97%, 98%, 92%, 99% and 98% for Criteria B.ConclusionOwing to high negative predictive value, the tADC threshold could be used to exclude subjects with clinically undetectable PCA. Adding the nodular size threshold, the combined threshold could identify the tADC‐positive segments that are likely to yield positive biopsy results. J. Magn. Reson. Imaging 2011;33:356–363. © 2011 Wiley‐Liss, Inc.
Susceptibility‐related MR signal dephasing under nonstatic conditions: Experimental verification and consequences for qBOLD measurements
Authors: Sohlin Maja C. , Schad Lothar R. 
Published: January 2011

AbstractPurposeTo experimentally verify a theoretical model describing the MR signal dephasing under nonstatic conditions in a voxel containing a vascular network, and to estimate the stability of the model for qBOLD measurements.Materials and MethodsMeasurement phantoms reflecting the properties of the theoretical model, i.e., statistically distributed and randomly oriented cylinders in a homogeneous medium were constructed by randomly coiled polyamide fibers immersed in a NiSO4 solution. The resemblance between measured and theoretical signal curves was investigated by calculation of root mean squared error maps. Simulated nonstatic dephasing data were evaluated using the static dephasing model to estimate the stability of the model and the influence of input parameters.ResultsThe theoretical model describing the MR signal dephasing under nonstatic conditions was experimentally verified in phantom measurements. In simulations, it was found that, by neglecting the effect of diffusion when predicting the MR signal‐time course expected in an in vivo measurement of the tissue oxygenation, errors of 10–30% would be introduced into the parameter estimation. The simulations indicate unpredictable results for simultaneous evaluation of blood oxygenation level and blood volume fraction.ConclusionNeglecting the effects of diffusion in quantitative BOLD measurements could give rise to substantial errors in the parameter estimation. J. Magn. Reson. Imaging 2011;33:417–425. © 2011 Wiley‐Liss, Inc.
Left ventricular diastolic function assessment from three‐dimensional three‐directional velocity‐encoded MRI with retrospective valve tracking
Authors: Brandts Anne , Bertini Matteo , van Dijk Evert‐Jan , Delgado Victoria , Marsan Nina Ajmone , van der Geest Rob J. , Siebelink Hans‐Marc J. , de Roos Albert , Bax Jeroen J. , Westenberg Jos J.M. 
Published: January 2011

AbstractPurposeTo compare parameters describing left ventricular (LV) diastolic function obtained with three‐dimensional (3D) three‐directional velocity‐encoded (VE) MRI with retrospective valve tracking and two‐dimensional (2D) one‐directional VE MRI in patients with ischemic heart failure. Second, to compare classification of LV diastolic function, and in particular for discriminating restrictive filling patterns, with both MRI techniques versus Doppler echocardiography.Materials and MethodsThe 3D and 2D VE MRI early (E) and atrial (A) peak flow rate indices, determined from transmitral waveform analyses, were compared. Also, net forward flow volume per cycle and transmitral regurgitation fraction were determined. Agreement in classifying diastolic filling patterns between 3D and 2D VE MRI versus Doppler echocardiography was evaluated using kappa statistics.ResultsThe 3D three‐directional VE MRI with retrospective valve tracking was statistically significantly different from 2D one‐directional VE MRI for net forward flow volume and regurgitation fraction through the mitral valve and all parameters describing the diastolic waveform filling pattern, except for the E deceleration time and E/A filling ratio. Kappa‐agreement between 3D three‐directional VE MRI with retrospective valve tracking and echocardiography for classifying diastolic filling patterns was superior to 2D one‐directional VE MRI and echocardiography (i.e., κ = 0.91 versus κ = 0.79, respectively).ConclusionThe 3D three‐directional VE MRI with retrospective valve tracking better describes LV diastolic function as compared to 2D one‐directional VE MRI in patients with ischemic heart failure. J. Magn. Reson. Imaging 2011;33:312–319. © 2011 Wiley‐Liss, Inc.
Support vector machine multiparametric MRI identification of pseudoprogression from tumor recurrence in patients with resected glioblastoma
Authors: Hu Xintao , Wong Kelvin K. , Young Geoffrey S. , Guo Lei , Wong Stephen T. 
Published: January 2011

AbstractPurposeTo automatically differentiate radiation necrosis from recurrent tumor at high spatial resolution using multiparametric MRI features.Materials and MethodsMRI data retrieved from 31 patients (15 recurrent tumor and 16 radiation necrosis) who underwent chemoradiation therapy after surgical resection included post‐gadolinium T1, T2, fluid‐attenuated inversion recovery, proton density, apparent diffusion coefficient (ADC), and perfusion‐weighted imaging (PWI) ‐derived relative cerebral blood volume (rCBV), relative cerebral blood flow (rCBF), and mean transit time maps. After alignment to post contrast T1WI, an eight‐dimensional feature vector was constructed. An one‐class‐support vector machine classifier was trained using a radiation necrosis training set. Classifier parameters were optimized based on the area under receiver operating characteristic (ROC) curve. The classifier was then tested on the full dataset.ResultsThe sensitivity and specificity of optimized classifier for pseudoprogression was 89.91% and 93.72%, respectively. The area under ROC curve was 0.9439. The distribution of voxels classified as radiation necrosis was supported by the clinical interpretation of follow‐up scans for both nonprogressing and progressing test cases. The ADC map derived from diffusion‐weighted imaging and rCBV, rCBF derived from PWI were found to make a greater contribution to the discrimination than the conventional images.ConclusionMachine learning using multiparametric MRI features may be a promising approach to identify the distribution of radiation necrosis tissue in resected glioblastoma multiforme patients undergoing chemoradiation. J. Magn. Reson. Imaging 2011;33:296–305. © 2011 Wiley‐Liss, Inc.
Detailed assessment of the hemodynamic response to psychosocial stress using real‐time MRI
Authors: Jones Alexander , Steeden Jennifer A. , Pruessner Jens C. , Deanfield John E. , Taylor Andrew M. , Muthurangu Vivek 
Published: January 2011

AbstractPurposeTo demonstrate that combining the Montreal Imaging Stress Task (MIST) with real‐time cardiac magnetic resonance imaging (MRI) allows detailed assessment of the cardiovascular mental stress response.Materials and Methods22 healthy volunteers (1:1 M:F, 26–64 years) underwent MRI during rest and the MIST. Real‐time spiral phase contrast MR, accelerated with sensitivity encoding (SENSE) was used to assess stroke volume (SV), and radial k‐t SENSE was used to assess ventricular volumes. Simultaneous heart rate (HR) and blood pressure (BP) measures allowed calculation of cardiac output (CO), systemic vascular resistance (SVR), and arterial compliance (TAC). Endocrine responses were assessed using salivary cortisol.ResultsIn response to stress, BP increased due to increased CO and reduced TAC but not increased SVR, which fell. HR, not SV, determined CO increases. Greater BP responses occurred in men due to greater CO increases and relatively higher SVR. Older participants had greater BP responses due to greater falls in TAC. Greater cortisol response was correlated with greater falls in TAC but resting cortisol and TAC were not related.ConclusionThis new approach allows detailed, accurate assessment of stress physiology. Preliminary findings suggest stress exposes relationships, not seen at rest, of cardiovascular function with age, sex, and endocrine function. J. Magn. Reson. Imaging 2011;33:448–454. © 2011 Wiley‐Liss, Inc.
Performance of μMRI‐Based virtual bone biopsy for structural and mechanical analysis at the distal tibia at 7T field strength
Authors: Bhagat Yusuf A. , Rajapakse Chamith S. , Magland Jeremy F. , Love James H. , Wright Alexander C. , Wald Michael J. , Song Hee Kwon , Wehrli Felix W. 
Published: January 2011

AbstractPurposeTo assess the performance of a 3D fast spin echo (FSE) pulse sequence utilizing out‐of‐slab cancellation through phase alternation and micro‐magnetic resonance imaging (μMRI)‐based virtual bone biopsy processing methods to probe the serial reproducibility and sensitivity of structural and mechanical parameters of the distal tibia at 7.0T.Materials and MethodsThe distal tibia of five healthy subjects was imaged at three timepoints with a 3D FSE sequence at 137 × 137 × 410 μm3 voxel size. Follow‐up images were retrospectively 3D registered to baseline images. Coefficients of variation (CV) and intraclass correlation coefficients (ICCs) for measures of scale and topology of the whole tibial trabecular bone (TB) cross‐section as well as finite‐element‐derived Young's and shear moduli of central cuboidal TB subvolumes (8 × 8 × 5 mm3) were evaluated as measures of reproducibility and reliability. Four additional cubic TB subregions (anterior, medial, lateral, and posterior) of similar dimensions were extracted and analyzed to determine associations between whole cross‐section and subregional structural parameters.ResultsThe mean signal‐to‐noise ratio (SNR) over the 15 image acquisitions was 27.5 ± 2.1. Retrospective registration yielded an average common analysis volume of 67% across the three exams per subject. Reproducibility (mean CV = 3.6%; range, 1.5%–5%) and reliability (ICCs, 0.95–0.99) of all parameters permitted parameter‐based discrimination of the five subjects in spite of the narrow age range (26–36 years) covered. Parameters characterizing topology were better able to distinguish two individuals who demonstrated similar values for scalar measurements (≈34% difference, P < 0.001). Whole‐section axial stiffness encompassing the cortex was superior at distinguishing two individuals relative to its central subregional TB counterpart (≈8% difference; P < 0.05). Interregion comparisons showed that although all parameters were correlated (mean R2 = 0.78; range 0.57–0.99), the strongest associations observed were those for the erosion index (mean R2 = 0.95, P ≤ 0.01).ConclusionThe reproducibility and structural and mechanical parameter‐based discriminative ability achieved in five healthy subjects suggests that 7T‐derived μMRI of TB can be applied towards serial patient studies of osteoporosis and may enable earlier detection of disease or treatment‐based effects. J. Magn. Reson. Imaging 2011;. © 2011 Wiley‐Liss, Inc.
Scan–Rescan reproducibility of carotid bifurcation geometry from routine contrast‐enhanced MR angiography
Authors: Bijari Payam B. , Antiga Luca , Wasserman Bruce A. , Steinman David A. 
Published: January 2011

AbstractPurposeTo demonstrate the feasibility of rapid and reliable geometric characterization of normal carotid bifurcation geometry from routine 3D contrast‐enhanced magnetic resonance (MR) angiograms.Materials and MethodsRepeat scans of 61 participants, acquired as part of the Atherosclerosis Risk in Communities (ARIC) Carotid MRI substudy, were digitally segmented using automated 3D level set methods, relying on an operator only to select the branch endpoints and thresholds for the 3D lumen surface initialization. Geometric factors characterizing the 3D lumen geometry were then extracted automatically.ResultsOf 122 scans, 117 could be segmented within 5 minutes each, with 40% being of sufficiently high quality to require less than 2 minutes each. Irrespective of scan quality, geometric factors were found to be highly reproducible, with intraclass correlation coefficients (ICCs) typically above 0.9. The reconstructed lumen surfaces were reproducible to <0.3 mm on average, comparable to previous MRI‐based reproducibility studies. Owing to the automated nature of the analysis, operator reliability was near‐perfect (ICC >0.99), with lumen surface differences <0.1 mm.ConclusionThe 3D geometry of the carotid bifurcation can be characterized rapidly and with a high degree of consistency, even for suboptimal image qualities. This bodes well for large‐scale retrospective or prospective studies aimed at teasing out the influence of local vs. systemic risk factors for early atherosclerosis. J. Magn. Reson. Imaging 2011;33:482–489. © 2011 Wiley‐Liss, Inc.
Fast spin‐echo triple echo dixon: Initial clinical experience with a novel pulse sequence for simultaneous fat‐suppressed and nonfat‐suppressed T2‐weighted spine magnetic resonance imaging
Authors: Low Russell N. , Austin Matthew J. , Ma Jingfei 
Published: January 2011

AbstractPurposeTo evaluate a prototype fast spin‐echo (FSE) triple‐echo Dixon (FTED) technique for T2‐weighted spine imaging with and without fat suppression compared to conventional T2‐weighted fast recovery (FR) FSE and short‐tau inversion recovery (STIR) imaging.Materials and MethodsSixty‐one patients were referred for spine magnetic resonance imaging (MRI) including sagittal FTED (time 2:26), STIR (time 2:42), and T2 FRFSE (time 2:55). Two observers compared STIR and FTED water images and T2 FRFSE and FTED T2 images for overall image quality, fat suppression, anatomic sharpness, motion, cerebrospinal fluid (CSF) flow artifact, susceptibility, and disease depiction.ResultsOn FTED images water and fat separation was perfect in 58 (.95) patients. Compared to STIR, the FTED water images demonstrated less motion in 57 (.93) of 61 patients (P < 0.05), better anatomic sharpness in 51 (.84) and patients (P < 0.05), and less CSF flow artifact in 7 (.11) P < 0.05) patients. There was no difference in fat suppression or chemical shift artifact. T2 FRFSE and FTED T2 images showed equivalent motion, CSF flow, and chemical shift artifact. Lesion depiction was equivalent on FTED water and STIR images and FTED T2 and T2 FRFSE images.ConclusionFTED efficiently provides both fat‐suppressed and nonfat‐suppressed T2‐weighted spine images with excellent image quality, equal disease depiction, and 56% reduction in scan time compared to conventional STIR and T2 FRFSE. J. Magn. Reson. Imaging 2011;33:390–400. © 2011 Wiley‐Liss, Inc.