bluuebunny/crossref_metadata_2025_split huggingface dataset:
Robust tissue–air volume segmentation of MR images based on the statistics of phase and magnitude: Its applications in the display of susceptibility‐weighted imaging of the brain
Authors: Du Yiping P. , Jin Zhaoyang 
Published: September 2009

AbstractPurposeTo develop a robust algorithm for tissue–air segmentation in magnetic resonance imaging (MRI) using the statistics of phase and magnitude of the images.Materials and MethodsA multivariate measure based on the statistics of phase and magnitude was constructed for tissue–air volume segmentation. The standard deviation of first‐order phase difference and the standard deviation of magnitude were calculated in a 3 × 3 × 3 kernel in the image domain. To improve differentiation accuracy, the uniformity of phase distribution in the kernel was also calculated and linear background phase introduced by field inhomogeneity was corrected. The effectiveness of the proposed volume segmentation technique was compared to a conventional approach that uses the magnitude data alone.ResultsThe proposed algorithm was shown to be more effective and robust in volume segmentation in both synthetic phantom and susceptibility‐weighted images of human brain. Using our proposed volume segmentation method, veins in the peripheral regions of the brain were well depicted in the minimum‐intensity projection of the susceptibility‐weighted images.ConclusionUsing the additional statistics of phase, tissue–air volume segmentation can be substantially improved compared to that using the statistics of magnitude data alone. J. Magn. Reson. Imaging 2009;30:722–731. © 2009 Wiley‐Liss, Inc.
Investigation using an HER‐2/neu transgenic mouse model of a newly developed MR contrast agent with the effect of an antitumor drug
Authors: Sonoda Akinaga , Nitta Norihisa , Ohta Shinich , Nitta‐Seko Ayumi , Murata Satoshi , Jo Jun‐ichiro , Tabata Yasuhiko , Takahashi Masashi , Tani Toru , Murata Kiyoshi 
Published: September 2009

AbstractPurposeTo assess whether Gd‐DTPA‐Gel‐Cis, a conjugate of gadolinium (Gd), cis diamminedichloroplatinum (Cis), diethylenetriaminepentaacetic acid (DTPA)‐dianhydride, and bovine gelatin (Gel) can be used as an intravascular contrast agent at MRI and as an antitumor cell proliferation agent in vitro.Materials and MethodsWe injected Gd‐DTPA‐Gel‐Cis (200 mg/mL) into the caudal vein of female HER‐2/neu transgenic mice with spontaneous mammary tumors. The tumor signal intensity was measured with a 0.3 Tesla MRI scanner. HER‐2/neu‐expressing NT cells were treated with Gd‐DTPA‐Gel‐Cis (5 μM cisplatin, 200 mg/mL Gel), Cis alone (5 μM cisplatin), or Gel alone (200 mg/mL gelatin). Differences of P < 0.05 were considered to be statistically significant.ResultsOn T1‐weighted MRI scans of mice injected with Gd‐DTPA‐Gel‐Cis we observed a 23% increase in signal intensity. The survival rates of cells exposed to Gd‐DTPA‐Gel‐Cis or Cis were 70.9% and 58.3%, respectively, of the survival rates observed after treatment with Gel alone. Gd‐DTPA‐Gel‐Cis showed significant toxicity (P < 0.05).ConclusionGd‐DTPA‐Gel‐Cis shows promise for use as an MRI contrast medium and as an antitumor agent. J. Magn. Reson. Imaging 2009;30:907–910. © 2009 Wiley‐Liss, Inc.
Effects of diffusion time on short‐range hyperpolarized 3He diffusivity measurements in emphysema
Authors: Gierada David S. , Woods Jason C. , Bierhals Andrew J. , Bartel Seth T. , Ritter Jon H. , Choong Cliff K. , Das Nitin A. , Hong Cheng , Pilgram Thomas K. , Chang Yulin V. , Jacob Richard E. , Hogg James C. , Battafarano Richard J. , Cooper Joel D. , Meyers Bryan F. , Patterson G. Alexander , Yablonskiy Dmitriy A. , Conradi Mark S. 
Published: September 2009

AbstractPurposeTo characterize the effect of diffusion time on short‐range hyperpolarized 3He magnetic resonance imaging (MRI) diffusion measurements across a wide range of emphysema severity.Materials and Methods3He diffusion MRI was performed on 19 lungs or lobes resected from 18 subjects with varying degrees of emphysema using three diffusion times (1.6 msec, 5 msec, and 10 msec) at constant b value. Emphysema severity was quantified as the mean apparent diffusion coefficient (ADC) and as the percentage of pixels with ADC higher than multiple thresholds from 0.30–0.55 cm2/sec (ADC index). Quantitative histology (mean linear intercept) was obtained in 10 of the lung specimens from 10 of the subjects.ResultsThe mean ADCs with diffusion times of 1.6, 5.0, and 10.0 msec were 0.46, 0.40, and 0.37 cm2/sec, respectively (P < 0.0001, analysis of variance [ANOVA]). There was no relationship between the ADC magnitude and the effect of diffusion time on ADC values. The mean linear intercept correlated with ADC (r = 0.91–0.94, P < 0.001) and ADC index (r = 0.78–0.92, P < 0.01) at all diffusion times.ConclusionDecreases in ADC with longer diffusion time were unrelated to emphysema severity. The strong correlations between the ADC at all diffusion times tested and quantitative histology demonstrate that ADC is a robust measure of emphysema. J. Magn. Reson. Imaging 2009;30:801–808. © 2009 Wiley‐Liss, Inc.
Algorithm‐based method for detection of blood vessels in breast MRI for development of computer‐aided diagnosis
Authors: Lin Muqing , Chen Jeon‐Hor , Nie Ke , Chang Daniel , Nalcioglu Orhan , Su Min‐Ying 
Published: September 2009

AbstractPurposeTo develop a computer‐based algorithm for detecting blood vessels that appear in breast dynamic contrast‐enhanced (DCE) magnetic resonance imaging (MRI), and to evaluate the improvement in reducing the number of vascular pixels that are labeled by computer‐aided diagnosis (CAD) systems as being suspicious of malignancy.Materials and MethodsThe analysis was performed in 34 cases. The algorithm applied a filter bank based on wavelet transform and the Hessian matrix to detect linear structures as blood vessels on a two‐dimensional maximum intensity projection (MIP). The vessels running perpendicular to the MIP plane were then detected based on the connectivity of enhanced pixels above a threshold. The nonvessel enhancements were determined and excluded based on their morphological properties, including those showing scattered small segment enhancements or nodular or planar clusters. The detected vessels were first converted to a vasculature skeleton by thinning and subsequently compared to the vascular track manually drawn by a radiologist.ResultsWhen evaluating the performance of the algorithm in identifying vascular tissue, the correct‐detection rate refers to pixels identified by both the algorithm and radiologist, while the incorrect‐detection rate refers to pixels identified by only the algorithm, and the missed‐detection rate refers to pixels identified only by the radiologist. From 34 analyzed cases the median correct‐detection rate was 85.6% (mean 84.9% ± 7.8%), the incorrect‐detection rate was 13.1% (mean 15.1% ± 7.8%), and the missed‐detection rate was 19.2% (mean 21.3% ± 12.8%). When detected vessels were excluded in the hot‐spot color‐coding of the CAD system, they could reduce the labeling of vascular vessels in 2.6%–68.6% of hot‐spot pixels (mean 16.6% ± 15.9%).ConclusionThe computer algorithm‐based method can detect most large vessels and provide an effective means in reducing the labeling of vascular pixels as suspicious on a DCE‐MRI CAD system. This algorithm may improve the workflow of radiologists using CAD for image display, but will be particularly useful for development of automated CAD that gives diagnostic impression. J. Magn. Reson. Imaging 2009;30:817–824. © 2009 Wiley‐Liss, Inc.
Improved correlation to quantitative DCE‐MRI pharmacokinetic parameters using a modified initial area under the uptake curve (mIAUC) approach
Authors: Cheng Hai‐Ling Margaret 
Published: September 2009

AbstractPurposeTo propose a modified initial area under the uptake curve (mIAUC) dynamic contrast‐enhanced (DCE)‐MRI approach to achieve better distinction of underlying physiology.Materials and MethodsThe mIAUC is formulated on common characteristics of tissue contrast uptake curves observed over a wide range of physiological conditions. The new metrics, IAUCKtrans and IAUCve, are related to the transfer constant (Ktrans) and interstitial volume (ve), respectively. Tissue uptake curves were simulated over a range of physiological values and analyzed using the proposed mIAUC, conventional IAUC, and Tofts' pharmacokinetic model.ResultsIAUCKtrans and IAUCve are highly correlated to the true Ktrans and ve (ρ = 0.97 and 0.95, respectively), approaching the performance of Tofts' model based on a 1.5‐s sampled arterial input function (AIF) (ρ = 0.98 and 0.98) under noise conditions typical in DCE‐MRI experiments. Lower correlations were obtained with conventional IAUC60 and IAUC120 (ρ = 0.82 and 0.61) and Tofts' parameters fitted using a biexponential AIF (ρ = 0.81 and 0.90).ConclusionThe proposed mIAUC approach retains advantages associated with nonmodel based methods (robust to noise and model fit failure, obviates need for an AIF) while providing better distinction of underlying physiological parameters. It can be a valuable alternative to pharmacokinetic modelling in the analysis of DCE‐MRI data. J. Magn. Reson. Imaging 2009;30:864–872. © 2009 Wiley‐Liss, Inc.
First‐pass and steady‐state magnetic resonance angiography of the thoracic vasculature using gadofosveset trisodium
Authors: Naehle Claas P. , Müller Andreas , Willinek Winfried A. , Meyer Carsten , Hestermann Tobias , Gieseke Juergen , Schild Hans , Thomas Daniel 
Published: September 2009

AbstractPurposeTo compare a high‐resolution, ECG‐gated, motion‐compensated, steady‐state magnetic resonance angiography (SS‐MRA) of the thoracic vasculature to standard first‐pass MRA (FP‐MRA) using a blood‐pool contrast agent (gadofosveset trisodium).Materials and MethodsIn all, 25 patients ≥18 years with congenital or acquired disease of the thoracic vasculature, who underwent both FP‐MRA and SS‐MRA, were retrospectively identified. Diameters of left superior pulmonary vein (LSPV), left pulmonary artery (LPA), and aortic arch (AA) were measured. Image quality for LSPV, LPA, AA, coronary ostia, and coronary sinus were assessed. Vessel sharpness of LPA and LSPV and contrast ratio (CR) of LSPV, LPA, and AA were calculated.ResultsSS‐MRA yielded significantly higher image quality for all vessels, and significantly higher vessel sharpness for LSPV and LPA compared to the FP‐MRA. SS‐MRA revealed lower intra‐ and interobserver variability for vessel diameters compared with the FP‐MRA. The FP‐MRA showed higher CR compared to the SS‐MRA.ConclusionMotion‐compensated high‐resolution SS‐MRA of the thoracic vasculature using gadofosveset trisodium offers superior image quality compared to standard FP‐MRA. Although SS‐MRA delivers no dynamic information it may prove specifically helpful as an add‐on to FP‐MRA for imaging of small vascular structures. J. Magn. Reson. Imaging 2009;30:809–816. © 2009 Wiley‐Liss, Inc.
Contrast‐enhanced myocardial T1‐weighted scout (Look–Locker) imaging for the detection of myocardial damages in hypertrophic cardiomyopathy
Authors: Amano Yasuo , Takayama Morimasa , Kumita Shinichiro 
Published: September 2009

AbstractPurposeTo assess the myocardial damage in hypertrophic cardiomyopathy (HCM) using contrast‐enhanced myocardial T1‐weighted scout (Look–Locker) magnetic resonance imaging (MRI).Materials and MethodsTwenty‐three patients with HCM and seven comparative patients without known HCM serving as controls underwent cine, contrast‐enhanced myocardial T1‐weighted scout and delayed‐enhancement MRI using a 1.5T unit. Intervals of null points between myocardium and blood were compared among hyperenhancing and nullified myocardium of HCM and the normal myocardium. The relationship between these myocardial patterns and global cardiac functions was analyzed in HCM.ResultsThe hyperenhancing myocardium, dense myocardial fibrosis in HCM had null points significantly shorter than blood, normal myocardium, and nullified myocardium of HCM (P < 0.0001). The number of hyperenhancing myocardial segments correlated with the ejection fraction (P = 0.045). The nullified myocardium of HCM showed shorter intervals of the null points between myocardium and blood than did the normal myocardium, indicating the dispersed myocardial fibrosis (P = 0.0032). The interval of null points between the nullified myocardium and blood showed a significant correlation with the increase in myocardial mass in HCM (P = 0.034).ConclusionContrast‐enhanced myocardial T1‐weighted scout imaging has the potential for showing dispersed myocardial damage leading to increased myocardial mass in HCM, while the dense myocardial fibrosis correlated with reduced ejection fraction. J. Magn. Reson. Imaging 2009;30:778–784. © 2009 Wiley‐Liss, Inc.
Initial feasibility of a multi‐station high resolution three‐dimensional dark blood angiography protocol for the assessment of peripheral arterial disease
Authors: Mihai Georgeta , Chung Yiu‐Cho , Kariisa Mbabazi , Raman Subha V. , Simonetti Orlando P. , Rajagopalan Sanjay 
Published: September 2009

AbstractPurposeTo evaluate the feasibility of a multi‐station three dimensional (3D) T1‐weighted turbo spin echo (TSE) dark‐blood Sampling Perfection with Application optimized Contrasts using different flip angle Evolution sequence (T1w‐SPACE), to assess aorta, iliac, and superficial femoral (SFA) arteries (inflow vessels) by comparing it with a multi‐station contrast enhanced MR angiography (CE‐MRA) with identical resolution.Materials and MethodsA total of 6 volunteers and 14 peripheral arterial disease (PAD) patients were included in the study. Abdominal and thigh T1w‐SPACE and lower leg time‐resolved MRA (TR‐MRA) with low dose contrast were followed by 3‐station CE‐MRA. Quantitative measurements of lumen area at 17 locations from T1w‐SPACE and CE‐MRA were obtained. Additionally, vessel wall areas at the same locations were obtained from the T1w‐SPACE images.ResultsQuantitative comparison of lumen areas with T1w‐SPACE and CE‐MRA revealed strong correlation between the two techniques and strong inter‐observer agreement for each of the two imaging methods (r > 0.9; P < 0.001). Localized vessel wall area measurements obtained in PAD patients were significantly greater compared with those obtained in normal volunteers (mean difference 43.75 ± 12.46 mm2; P < 0.001). Stenosis severity obtained from T1w‐SPACE localized measurements showed significant arterial area stenosis in PAD patients.ConclusionT1w‐SPACE imaging of inflow vessels is feasible, and in addition to CE‐MRA has the ability to assess atherosclerotic plaque and vascular remodeling. J. Magn. Reson. Imaging 2009;30:785–793. © 2009 Wiley‐Liss, Inc.
Atypical imaging appearance of toxoplasmosis in an HIV patient as a butterfly lesion
Authors: Chaudhari Vinika V. , Yim Catherine M. , Hathout Heba , Lai Andrew , Donovan Suzanne M. 
Published: September 2009

AbstractIn acquired immunodeficiency syndrome (AIDS) patients, differentiating toxoplasmosis and primary central nervous system (CNS) lymphoma remains a clinical and radiographic dilemma. The presence of butterfly lesions crossing the corpus callosum is customarily used to exclude the possibility of toxoplasmosis. We present an AIDS patient who had Epstein‐Barr virus (EBV) polymerase chain reaction (PCR) ‐positive cerebrospinal fluid studies with a butterfly toxoplasmosis lesion confirmed by multiple methods signifying the importance of including toxoplasmosis in the differential diagnosis of butterfly lesions. J. Magn. Reson. Imaging 2009;30:873–875. © 2009 Wiley‐Liss, Inc.
Use of a novel ionic liquid matrix for MALDI‐MS analysis of glycopeptides and glycans out of total tryptic digests
Authors: Ullmer Roman , Rizzi Andreas M. 
Published: September 2009

AbstractIn this study, we investigated a novel ionic liquid matrix (ILM), namely, the 1,1,3,3‐tetramethylguanidinium salt of 2,4,6‐trihydroxyacetophenone (THAP). This matrix[1,1,3,3‐tetramethylguanidinium 2,4,6‐trihydroxyacetophenone (GTHAP)] turned out to be well suited for the matrix‐assisted laser desorption/ionization mass spectrometric analysis of glycopeptides and glycans, and overcame the well‐known ionization suppression of carbohydrate structures in the presence of peptides. The matrix was evaluated by two different series of experiments, in each case in comparison with the crystalline THAP matrix. In the first set of experiments, mass spectra were taken from unseparated tryptic digests of three glycoproteins taken as model compounds. Even glycopeptides containing short peptide backbones and large carbohydrate moieties gave high signal intensities when using the ILM though they did not appear in the THAP spectra. In the second set of experiments, the total tryptic digests were treated with endoglycosidase PNGase F to cleave off the N‐linked glycans. When using the GTHAP matrix, it was possible to detect the glycans with high intensities in the presence of the tryptic peptides, whereas glycan ionization was completely suppressed when measured with the solid matrix THAP. The extent of metastable decay of glycopeptides was reduced when using the ILM. Altogether, GTHAP proved as a useful ILM particularly being superior to solid matrices in the context of glycosylation analysis. Copyright © 2009 John Wiley & Sons, Ltd.
Improved identification of hordeins by cysteine alkylation with 2‐bromoethylamine, SDS‐PAGE and subsequent in‐gel tryptic digestion
Authors: Řehulková Helena , Marchetti‐Deschmann Martina , Pittenauer Ernst , Allmaier Günter , Řehulka Pavel 
Published: September 2009

AbstractProteomic‐based description of varieties of barley (Hordeum vulgare L.) is a very important task especially in the food and brewing industry. This study is focused on major storage proteins in barley—hordeins—as a group of proteins soluble in alcohol/water mixtures that shows up significant changes in proteomic profiles for different varieties of barley. Unusual amino acid composition of hordeins with low numbers of lysine and arginine in combination with high content of proline and glutamine complicates their identification in a common proteomic workflow, because tryptic digestion produces just a few peptides amenable for successful mass spectrometric analysis. To increase the number of cleavage sites, in this work, cysteines in hordeins were chemically modified with 2‐bromoethylamine (BEA) for their conversion into aminoethylcysteines. These mimic lysine residues and are recognized by trypsin as potentional cleavage sites (if not followed by a proline residue) on the C‐terminal side of the modified cysteine. Small extent of side reactions (towards histidine, N‐terminus of the peptide, methionine, and also here the newly discovered reaction towards aminoethylcysteine) during modification with BEA could be observed after a longer period of reaction but this did not hinder the analysis when optimal conditions were used. Application of trypsin for in‐gel digestion of hordeins, previously modified chemically with BEA, provided a higher number of short peptides and their subsequent mass spectrometric analysis resulted in an improved identification of hordeins. This approach can also be used for the analysis of other similar protein groups (e.g. gliadins in wheat) or other cysteines containing proteins having a low number of lysine and arginine residues in their primary structure. Copyright © 2009 John Wiley & Sons, Ltd.
Light beats the spread: “non‐diffracting” beams
Authors: Mazilu M. , Stevenson D.James , Gunn‐Moore F. , Dholakia K. 
Published: September 2009

Abstract“Non‐diffracting” beams do not spread as they propagate. This property is useful in many areas. Here, the theory, generation, properties, and applications of various “non‐diffracting” beams, including the Bessel beam, Mathieu beam, and Airy beam is reviewed. Applications include imaging, micromanipulation, nonlinear optics, and optical transfection.
The progress towards terahertz quantum cascade lasers on silicon substrates
Authors: Paul D.J. 
Published: September 2009

AbstractA review is presented of work over the last 10 years which has been aimed at trying to produce a Si‐based THz quantum cascade laser. Potential THz applications and present THz sources will be briefly discussed before the materials issues with the Si/SiGe system is discussed. Waveguide designs and waveguide losses will be presented. Experimental measurements of the non‐radiative lifetimes for intersubband transitions in Si1‐xGexquantum wells will be presented along with theory explaining the important scattering mechanisms which determine the lifetimes. Examples of p‐type Si/SiGe quantum cascade designs with the experimental electroluminescence will be reviewed and examples of n‐type Si‐based designs will be presented. In the conclusion designs and structures will be discussed with the greatest potential to achieve an electrically pumped Si‐based THz laser.
Bacterially induced degradation of aqueous solutions of poly(l‐lysine)‐graft‐poly(ethylene glycol) and poly(l‐lysine)‐graft‐dextran: consequences for their lubrication properties
Authors: Argibay Nicolas , Perrino Chiara , Rimann Markus , Lee Seunghwan , Spencer Nicholas D. 
Published: September 2009

AbstractExperimental data are presented comparing the degradation in the lubrication behaviour of aqueous solutions of the brush copolymers poly(l‐lysine)‐graft‐poly(ethylene glycol) (PLL‐g‐PEG) and poly(l‐lysine)‐graft‐dextran (PLL‐g‐dex) when aged after exposure to bacterial contamination. While PLL‐g‐PEG solutions appear to be relatively unaffected by bacteria after a storage period of as much as 8 weeks, PLL‐g‐dex solutions exposed to bacteria during preparation lead to as much as a twofold increase in friction coefficient, when used as a lubricant in tribological tests, over an 8 week period when compared to reference data from freshly prepared and tested samples. Solutions prepared under sterile conditions and aged for up to 8 weeks do not appear to be degraded. Further experiments implementing the anti‐bacterial agent sodium azide effectively prevented bacterial colonization and degradation in lubrication behaviour. Copyright © 2009 John Wiley & Sons, Ltd.
The value of assessing weights in multi‐criteria portfolio decision analysis
Authors: Keisler Jeffrey M. 
Published: September 2009

AbstractAnalytic efforts in support of portfolio decisions can be applied with varying levels of intensity. To gain insight about how to match the effort to the situation, we simulate a portfolio of potential projects and compare portfolio performance under a range of analytic strategies. Each project is scored with respect to several attributes in a linear additive value model. Projects are ranked in order of value per unit cost and funded until the budget is exhausted. Assuming these weights and scores are correct, and the funding decisions made this way are optimal, this process is a gold standard against which to compare other decision processes. In particular, a baseline process would fund projects essentially at random, and we may estimate the value added by various decision processes above this worst case as a percentage of the increase arising from the optimal process. We consider several stylized decision rules and combinations of them: using equal weights, picking one attribute at random, assessing weights from a single randomly selected stakeholder. Simulation results are then used to identify which conditions tend to make which types of analytic strategies valuable, and to identify useful hybrid strategies. Copyright © 2009 John Wiley & Sons, Ltd.