bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of shot number on the calculated apparent diffusion coefficient in phantoms and in human liver in diffusion‐weighted echo‐planar imaging
Authors: Shiehmorteza Masoud , Sirlin Claude B. , Wolfson Tanya , Gamst Anthony , Soumekh Andre E. , Heaton Shay P. , Kohl Chad A. , Pinto Nicholas , Bydder Mark 
Published: August 2009

AbstractPurposeTo show the signal intensity varies with shot number in diffusion‐weighted (DW) echo‐planar imaging (EPI) and affects apparent diffusion coefficient (ADC) calculation.Materials and MethodsThis prospective study was performed on 35 adult patients and 20 volunteers. Measurements were made on a 3T scanner using a breathhold DW spin‐echo EPI (SE EPI) sequence. Three protocols were used: A) eight consecutive shots at a fixed b‐value of 0 seconds/mm2 with TR = 1000 and 3000 msec; B) seven consecutive shots at b‐values = 0, 1000, 750, 500, 250, 100, 0 seconds/mm2 (in that order) with TR = 3500 msec; and C) seven consecutive shots (as in B) with TR = 1000, 1750, and 7000 msec.ResultsFor protocol A, signal intensity decreased significantly from the first to second shot (P<0.0001) and thereafter remained constant. For protocol B, the ADC depended on which b = 0 seconds/mm2 image was used. Using the first b = 0 seconds/mm2, the mean ADC was 15% higher than using the second b = 0 seconds/mm2 (P<0.0001). For protocol C, the difference between ADC using the first b = 0 seconds/mm2 and the second b = 0 seconds/mm2 decreased as the TR increased.ConclusionThe signal intensity can vary with shot number in SE EPI. For TR ≥ 3000 msec, steady‐state is attained after one shot. Using data acquired prior to steady‐state confounds the calculation of ADC values. J. Magn. Reson. Imaging 2009;30:547–553. © 2009 Wiley‐Liss, Inc.
Segmentation of human skull in MRI using statistical shape information from CT data
Authors: Wang Defeng , Shi Lin , Chu Winnie C.W. , Cheng Jack C.Y. , Heng Pheng Ann 
Published: August 2009

AbstractPurposeTo automatically segment the skull from the MRI data using a model‐based three‐dimensional segmentation scheme.Materials and MethodsThis study exploited the statistical anatomy extracted from the CT data of a group of subjects by means of constructing an active shape model of the skull surfaces. To construct a reliable shape model, a novel approach was proposed to optimize the automatic landmarking on the coupled surfaces (i.e., the skull vault) by minimizing the description length that incorporated local thickness information. This model was then used to locate the skull shape in MRI of a different group of patients.ResultsCompared with performing landmarking separately on the coupled surfaces, the proposed landmarking method constructed models that had better generalization ability and specificity. The segmentation accuracies were measured by the Dice coefficient and the set difference, and compared with the method based on mathematical morphology operations.ConclusionThe proposed approach using the active shape model based on the statistical skull anatomy presented in the head CT data contributes to more reliable segmentation of the skull from MRI data. J. Magn. Reson. Imaging 2009;30:490–498. © 2009 Wiley‐Liss, Inc.
Computer‐aided detection of brain tumor invasion using multiparametric MRI
Authors: Jensen Todd R. , Schmainda Kathleen M. 
Published: August 2009

AbstractPurposeTo determine the potential of using a computer‐aided detection method to intelligently distinguish peritumoral edema alone from peritumor edema consisting of tumor using a combination of high‐resolution morphological and physiological magnetic resonance imaging (MRI) techniques available on most clinical MRI scanners.Materials and MethodsThis retrospective study consisted of patients with two types of primary brain tumors: meningiomas (n = 7) and glioblastomas (n = 11). Meningiomas are typically benign and have a clear delineation of tumor and edema. Glioblastomas are known to invade outside the contrast‐enhancing area. Four classifiers of differing designs were trained using morphological, diffusion‐weighted, and perfusion‐weighted features derived from MRI to discriminate tumor and edema, tested on edematous regions surrounding tumors, and assessed for their ability to detect nonenhancing tumor invasion.ResultsThe four classifiers provided similar measures of accuracy when applied to the training and testing data. Each classifier was able to identify areas of nonenhancing tumor invasion supported with adjunct images or follow‐up studies.ConclusionThe combination of features derived from morphological and physiological imaging techniques contains the information necessary for computer‐aided detection of tumor invasion and allows for the identification of tumor invasion not previously visualized on morphological, diffusion‐weighted, and perfusion‐weighted images and maps. Further validation of this approach requires obtaining spatially coregistered tissue samples in a study with a larger sample size. J. Magn. Reson. Imaging 2009;30:481–489. © 2009 Wiley‐Liss, Inc.
MR imaging of endometrial carcinoma for preoperative staging at 3.0 T: Comparison with imaging at 1.5 T
Authors: Hori Masatoshi , Kim Tonsok , Murakami Takamichi , Imaoka Izumi , Onishi Hiromitsu , Nakamoto Atsushi , Nakaya Yasuhiro , Tomoda Kaname , Tsutsui Tateki , Enomoto Takayuki , Kimura Tadashi , Nakamura Hironobu 
Published: August 2009

AbstractPurposeTo prospectively compare magnetic resonance imaging (MRI) at 3.0 T and 1.5 T in the same patients for preoperative evaluation of endometrial carcinoma.Materials and MethodsThirty consecutive patients with endometrial carcinoma underwent MRI at both 3.0 T and 1.5 T as well as surgery. Quantitative and qualitative analyses were performed. Two radiologists independently evaluated images. MR findings were compared with surgicopathologic findings.ResultsImage homogeneity of T2‐weighted images at 3.0 T was significantly inferior to that at 1.5 T (P = 0.007). The scores of image homogeneity and susceptibility artifacts were not significantly different between 3.0 T gadolinium‐enhanced imaging and 1.5 T imaging (P = 0.09 and 0.36). Kappa statistics showed good interobserver agreement between the two radiologists for local‐regional staging on T2‐weighted images (κ>0.6). The area under the receiver operating characteristic curve (Az) values for T2‐weighted imaging in terms of myometrial invasion, cervical invasion, and lymph node metastases were 0.88 (3.0 T) versus 0.91 (1.5 T), 0.84 versus 0.83, and 0.94 versus 0.95 for reader 1, respectively. There were no significant differences between imaging at 3.0 T and at 1.5 T in Az values for either reader (P > 0.35).Conclusion3.0 T MRI is an equivalent imaging modality to 1.5 T imaging for presurgical evaluation of endometrial carcinoma, although not significantly superior to 1.5 T imaging. J. Magn. Reson. Imaging 2009;30:621–630. © 2009 Wiley‐Liss, Inc.
Half‐fourier‐acquisition single‐shot turbo spin‐echo (HASTE) MRI of the lung at 3 Tesla using parallel imaging with 32‐receiver channel technology
Authors: Henzler Thomas , Dietrich Olaf , Krissak Radko , Wichmann Tobias , Lanz Titus , Reiser Maximilian F. , Schoenberg Stefan O. , Fink Christian 
Published: August 2009

AbstractPurposeTo assess the feasibility of half‐Fourier‐acquisition single‐shot turbo spin‐echo (HASTE) of the lung at 3 Tesla (T) using parallel imaging with a prototype of a 32‐channel torso array coil, and to determine the optimum acceleration factor for the delineation of intrapulmonary anatomy.Materials and MethodsNine volunteers were examined on a 32‐channel 3T MRI system using a prototype 32‐channel‐torso‐array‐coil. HASTE‐MRI of the lung was acquired at both, end‐inspiratory and end‐expiratory breathhold with parallel imaging (Generalized autocalibrating partially parallel acquisitions = GRAPPA) using acceleration factors ranging between R = 1 (TE = 42 ms) and R = 6 (TE = 16 ms). The image quality of intrapulmonary anatomy and subjectively perceived noise level was analyzed by two radiologists in consensus. In addition quantitative measurements of the signal‐to‐noise ratio (SNR) of HASTE with different acceleration factors were assessed in phantom measurements.ResultsUsing an acceleration factor of R = 4 image blurring was substantially reduced compared with lower acceleration factors resulting in sharp delineation of intrapulmonary structures in expiratory scans. For inspiratory scans an acceleration factor of 2 provided the best image quality. Expiratory scans had a higher subjectively perceived SNR than inspiratory scans.ConclusionUsing optimized multi‐element coil geometry HASTE‐MRI of the lung is feasible at 3T with acceleration factors up to 4. Compared with nonaccelerated acquisitions, shorter echo times and reduced image blurring are achieved. Expiratory scanning may be favorable to compensate for susceptibility associated signal loss at 3T. J. Magn. Reson. Imaging 2009;30:541–546. © 2009 Wiley‐Liss, Inc.
Initial experience on utility of gadobenate dimeglumine (Gd‐BOPTA) enhanced T1‐weighted MR cholangiography in diagnosis of acute cholecystitis
Authors: Akpinar Erhan , Turkbey Baris , Karcaaltincaba Musturay , Balli Omur , Akkapulu Nezih , Balas Sener , Tirnaksiz Bulent , Akata Deniz , Akhan Okan 
Published: August 2009

AbstractPurposeTo investigate the feasibility of the use of gadobenate dimeglumine (also known as Gd‐BOPTA) ‐enhanced T1‐weighted MR cholangiography in diagnosis of acute cholecystitis.Materials and MethodsThis prospectively designed institutional review board‐approved HIPAA‐compliant study was done between January and November 2007. We included 11 consecutive patients (7 male, mean age 59 years) who presented to the emergency room with acute right upper quadrant pain and with equivocal physical examination and/or ultrasound findings. The control group included 15 patients who underwent liver MRI with Gd‐BOPTA. All patients underwent contrast‐enhanced (CE) MR cholangiography examinations. CE‐MR cholangiography was performed on a 1.5 Tesla magnet using 3D T1‐weighted high resolution isotrophic volume examination (THRIVE) obtained at the 90th min after intravenous injection of Gd‐BOPTA. Imaging features detected on CE‐MR cholangiography were correlated with operative and histopathologic findings.ResultsIn the control group, GD‐BOPTA was visualized within the gallbladder in all subjects. For the study group, gallstones were present in nine patients (n = 7 both in gallbladder and cystic duct, n = 1 only in gallbladder, n = 1 only in cystic duct) on MRCP. Hydropic gallbladder was detected in seven patients, significant wall thickening in seven patients, and pericholecystic free fluid in 6 patients. On delayed phase CE cholangiography, significant enhancement of gallbladder wall was seen in 10 patients, and contrast agent excretion into gallbladder was absent in all patients. Surgery was performed in 10 patients, and cholecystostomy was done in 1 patient. Surgery and histopathology findings were consistent with cholecystitis in all patients.ConclusionIn addition to anatomical assessment, Gd‐BOPTA‐enhanced MR cholangiography can provide functional evaluation similar to HIDA scintigraphy in diagnosing acute cholecystitis in patients with acute right upper quadrant pain and equivocal findings. J. Magn. Reson. Imaging 2009;30:578–585. © 2009 Wiley‐Liss, Inc.
Use of cardiac output to improve measurement of input function in quantitative dynamic contrast‐enhanced MRI
Authors: Zhang Jeff L. , Rusinek Henry , Bokacheva Louisa , Chen Qun , Storey Pippa , Lee Vivian S. 
Published: August 2009

AbstractPurposeTo validate a new method for converting MR arterial signal intensity versus time curves to arterial input functions (AIFs).Materials and MethodsThe method constrains AIF with patient's cardiac output (Q). Monte Carlo simulations of MR renography and tumor perfusion protocols were carried out for comparison with two alternative methods: direct measurement and population‐averaged input function. MR renography was performed to assess the method's inter‐ and intraday reproducibility for renal parameters.ResultsIn simulations of tumor perfusion, the precision of the parameters (Ktrans and ve) computed using the proposed method was improved by at least a factor of three compared to direct measurement. Similar improvements were obtained in simulations of MR renography. Volunteer study for testing interday reproducibility confirmed the improvement of precision in renal parameters when using the proposed method compared to conventional methods. In another patient study (two injections within one session), the proposed method significantly increased the correlation coefficient (R) between GFR of the two exams (0.92 vs. 0.83) compared to direct measurement.ConclusionA new method significantly improves the precision of dynamic contrast‐enhanced (DCE) parameters. The method may be especially useful for analyzing repeated DCE examinations, such as monitoring tumor therapy or angiotensin converting enzyme‐inhibitor renography. J. Magn. Reson. Imaging 2009;30:656–665. © 2009 Wiley‐Liss, Inc.
Quantitation of the main constituents of vanilla by reverse phase HPLC and ultra‐high‐pressure‐liquid‐chromatography with UV detection: Method validation and performance comparison
Authors: Cicchetti Esmeralda , Chaintreau Alain 
Published: August 2009

AbstractVanilla's main constituents, i. e., vanillin, para‐hydroxybenzaldehyde, and their corresponding acids, can be easily quantified by RP LC with UV detection and external calibration. This paper describes two methods that were developed using HPLC and ultra‐high‐pressure LC (UHPLC), respectively, and validated according to the International Conference on Harmonisation of Technical Requirements for Registration of Pharmaceuticals for Human Use (ICH) [1]. Both methods were highly specific, exhibited good linearities with high precision, and achieved good accuracies of quantitative results. The UHPLC method was more sensitive, five times shorter, and gave better peak resolutions than the HPLC alternative.
A data base for polymer chromatography: Temperature dependence of interaction parameters in liquid adsorption chromatography
Authors: Trathnigg Bernd , Viet Cuong Nguyen , Ahmed Hasnat 
Published: August 2009

AbstractThe temperature dependence of retention behaviour of polyethylene glycol (PEG) and its mono‐ and dimethyl ethers was studied on various RP columns in different mobile phases. The accessible volumes and the interaction parameters were determined from slope and intercept in a plot of the elution volumes of the oligomers of a polymer homologous series as a function of the difference of the elution volumes of consecutive oligomers. A quite different dependence of the interaction parameters was observed in the different mobile phases. While in methanol–water the interaction parameter decreases with increasing temperature, the opposite effect is observed in acetonitrile (ACN)–water. In acetone–water, the temperature dependence is almost negligible.
Potential application of antioxidant capacity assays to assess the quality of edible vegetable oils
Authors: Castelo‐Branco Vanessa N. , Torres Alexandre G. 
Published: August 2009

AbstractThe total antioxidant capacity of edible vegetable oils corresponds to the integrated action of the complex mixture of antioxidant components against oxidation reactions in these oils, and takes into account potential physical and chemical interactions between oil components. Consequently, the total antioxidant capacity might be an indicator of quality attributes of edible oils, such as bioactivity and oxidative stability. In this paper we present an overview of the antioxidant capacity assays currently applied to the analysis of edible oils, and we briefly review current evidence indicating associations of the total antioxidant capacity (TAC) with the bioactivity and the oxidative stability of vegetable oils. Based on these data, we discuss the potential application of TAC assays for integrated quality control of edible vegetable oils, which includes bioactivity and oxidative stability.
Poly(carbazole)‐Based Copolymers Containing Deep‐Blue Chromophore for Polymer Light‐Emitting Diode Applications
Authors: Park Jin Su , Song Myungkwan , Jin Sung‐Ho , Lee Jae Wook , Lee Chan Woo , Gal Yeong‐Soon 
Published: August 2009

AbstractA new series of two poly(carbazole)‐based copolymers (poly(9‐hexyl‐carbazole‐co‐9‐(6‐(3‐(4‐phenylquinolin‐2‐yl)carbazol‐9‐yl)hexyl)carbazole) (PCVz) and poly(9,9‐dioctylfluorene‐co‐9‐(6‐(3‐(4‐phenylquinolin‐2‐yl)carbazol‐9‐yl)hexyl)carbazole) (PFCVz)) containing carbazoylphenylquinoline pendant groups were synthesized via the Suzuki coupling reaction for polymer light‐emitting diode applications. The electro‐optical properties of ITO/PEDOT/Polymer/PBD/LiF/Al devices based on these copolymers were investigated using UV‐visible, photoluminescence, and electroluminescence spectroscopy. The turn‐on voltages of the copolymer devices were found to be 6.0–8.0 V. The maximum brightness and luminescence efficiency of the copolymers device were found to be 230 cd · m−2 and 0.28 cd · A−1 at 11 V, respectively.magnified image
Polymer‐Infiltrated Aligned Carbon Nanotube Fibers by in situ Polymerization
Authors: Zhang Shanju , Zhu Lingbo , Wong Ching‐Ping , Kumar Satish 
Published: August 2009

AbstractCarbon nanotube–polymer composite fibers are obtained by infiltration of a monomer liquid into aligned carbon nanotube aerogel fibers with subsequent in situ polymerization. The monomer, methyl methacrylate (MMA), was infiltrated into the aerogel fibers of multi‐walled carbon nanotubes (MWNTs) at room temperature and subsequently polymerized at 50 °C into poly(methyl methacrylate) (PMMA). Cross‐sections of the PMMA/MWNT composite fibers showed that the PMMA filled the spaces of the nanotube fibers and bound the nanotubes together. PMMA in the composite fibers exhibited local order. The resultant composite fibers with 15 wt.‐% nanotube loading exhibited a 16‐fold and a 49‐fold increase in tensile strength and Young's modulus, respectively, compared to the control PMMA.magnified image
Construction of Large‐Scale Highly Ordered Macroporous Monoliths of π‐Conjugated Polymers
Authors: Zuo Zicheng , Guo Yanbing , Li Yuliang , Lv Jing , Liu Huibiao , Xu Jialiang , Li Yongjun 
Published: August 2009

AbstractLarge scale of well‐ordered macroporous π‐conjugated polymer monoliths have been successfully prepared through a new approach using micrometer‐sized naphthalene crystals as templates. The macroporous monoliths of poly(p‐phenylenevinylene) (PPV) and poly(p‐phenyleneethynylene) (PPE) grew along the unidirectional freezing direction inside the template naphthalene crystals which lead to the formation of controlling morphologies and homogeneous diameters. The polymer monoliths show straight and lamella macroporous structures. The diameters of pores and the thickness of pore walls can be controlled by tuning the freezing temperature.magnified image
Cyclopolymerization of Nonconjugated Dienes with a Tridentate Phenoxyamine Hafnium Complex Supported by an sp3‐C Donor: Isotactic Enchainment and Diastereoselective cis‐Ring Closure
Authors: Edson Joseph B. , Coates Geoffrey W. 
Published: August 2009

AbstractCyclopolymerization of nonconjugated dienes produces poly(methylene‐1,3‐cycloalkanes) and provides a pathway to a number of stereochemically complex polymers. Activation of a diastereomeric mixture of a six‐membered metallacycle complex (rac‐1) in the presence of 1,5‐hexadiene produced poly(methylene‐1,3‐cyclopentane) (PMCP) with >98% cyclization of the diene monomer. The catalyst was found to cyclopolymerize 1,5‐hexadiene with relatively high activity. The microstructure of the PMCP furnished by rac‐1 was found to contain a high proportion of cis‐cyclopentane rings (σ = 0.70–0.74) and a relatively high isotactic content (α = 0.93–0.96). These are the first cis‐enriched isotactic cyclopolymers of 1,5‐hexadiene. Cyclopolymerization of 1,6‐heptadiene with rac‐1/B(C6F5)3 produced poly(methylene‐1,3‐cyclohexane) containing 97% cis‐isotactic rings. This is the first report of this highly isotactic and diastereomerically‐pure microstructure.magnified image
Electrochemical Polymerisation of N‐Arylated and N‐Alkylated EDOT‐Substituted Pyrrolo[3,4‐c]pyrrole‐1,4‐dione (DPP) Derivatives: Influence of Substitution Pattern on Optical and Electronic Properties
Authors: Zhang Kai , Tieke Bernd , Forgie John C. , Skabara Peter J. 
Published: August 2009

AbstractNew pyrrolo[3,4‐c]pyrrole‐1,4‐dione (DPP) derivatives carrying 3,4‐ethylenedioxy‐thiophenylphenyl (EDOT‐phenyl) substituent groups in the 3‐ and 6‐position, or in the 2‐ and 5‐position of the DPP chromophore were synthesised and electrochemically polymerised. The properties of the polymers were investigated using cyclic voltammetry and UV/Vis absorption spectroscopy. It was found that the optical and electronic properties differ greatly between the two polymers. Materials with EDOT‐phenyl groups in the 3‐ and 6‐positions represent conjugated polymers with a low oxidation potential and reversible electrochromic properties, whereas the polymer with EDOT‐phenyl groups in the 2‐ and 5‐positions is non‐conjugated and possesses a high oxidation potential and irreversible redox behaviour.magnified image
De novo germline TP53 mutation presenting with synchronous malignancies of the central nervous system
Authors: Schniederjan Matthew J. , Shehata Bahig , Brat Daniel J. , Esiashvili Natia , Janss Anna J. 
Published: August 2009

AbstractWe present a case of a 14‐year‐old male with a germline TP53 mutation who presented with synchronous primitive neuroectodermal tumor and choroid plexus carcinoma. Identification of synchronous brain tumors prompted genetic testing for predisposition to malignancy. Within 5 months of presentation, the child developed widely metastatic alveolar rhabdomyosarcoma. Patient DNA sequencing showed a TP53 allele with a premature stop codon in the oligomerization/nuclear export signal (NES) domain (R342ter). The child's parents, younger brother, paternal grandparents, and maternal grandmother, are without history of malignancy. The patient's brother tested negative for TP53 mutations. This case identifies a rare, de novo, germline TP53 mutation presenting with synchronous CNS malignancies and exhibiting a more fulminant course than typical cases of Li–Fraumeni syndrome. Pediatr Blood Cancer 2009; 53:1352–1354. © 2009 Wiley‐Liss, Inc.