bluuebunny/crossref_metadata_2025_split huggingface dataset:
Assessment of left ventricular function by breath‐hold cine MR imaging: Comparison of different steady‐state free precession sequences
Authors: Kunz R. Peter , Oellig Florian , Krummenauer Frank , Oberholzer Katja , Romaneehsen Bernd , Vomweg Toni W. , Horstick Georg , Hayes Carmel , Thelen Manfred , Kreitner Karl‐Friedrich 
Published: January 2005

AbstractPurposeTo compare steady‐state free precession (SSFP) sequence protocols with different acquisition times (TA) and temporal resolutions (tRes) due to the implementation of a view sharing technique called shared phases for the assessment of left ventricular (LV) function by breath‐hold cine magnetic resonance (MR) imaging.Materials and MethodsEnd‐diastolic and end‐systolic volumes (EDV, ESV) were measured in contiguous short‐axis slices with a thickness of 8 mm acquired in 10 healthy male volunteers. The following true fast imaging with steady‐state precession (TrueFISP) sequence protocols were compared: protocol A) internal standard of reference, segmented: tRes 34.5 msec, TA 18 beats per slice; protocol B) segmented, shared phases: tRes 34.1 msec, TA 10 beats per slice; and protocol C) real‐time, shared phases, parallel acquisition technique: tRes 47.3 msec, TA 24 beats for 12 slices covering the entire left ventricle.ResultsPhase sharing leads to a significant decrease in EDV, stroke volume (SV), and ejection fraction (EF) (median difference −7.0 mL [*], −9.6 mL, and −3.4%, respectively, for protocol B; −15.3 mL, −13.3 mL, and −2.4% for protocol C; P = 0.002, *P = 0.021). The observed median difference of real‐time EDV and SV estimates is of clinical relevance. Real‐time cine MR imaging shows a greater variability of EDV and SV. No relevant differences in ESV were observed.ConclusionThe true cine frame duration of both shared phases sequence protocols exceeds the period of isovolumetric contraction (IVCT) of the left ventricle resulting in a systematic and significant underestimation of EDV and consequently SV and EF. SSFP sequence protocol par‐ameters, particularly tRes and use of view sharing techniques, should therefore be known at follow‐up examinations in order to be able to assess LV remodeling in patients with heart failure. J. Magn. Reson. Imaging 2005;21:140–148. © 2005 Wiley‐Liss, Inc.
The role of edema and demyelination in chronic T1 black holes: A quantitative magnetization transfer study
Authors: Levesque Ives , Sled John G. , Narayanan Sridar , Santos A. Carlos , Brass Steven D. , Francis Simon J. , Arnold Douglas L. , Pike G. Bruce 
Published: January 2005

AbstractPurposeTo use quantitative magnetization transfer imaging (qMTI) in an investigation of T1‐weighted hypointensity observed in clinical magnetic resonance imaging (MRI) scans of multiple sclerosis (MS) patients, which has previously been proposed as a more specific indicator of tissue damage than the more commonly detected T2 hyperintensity.Materials and MethodsA cross‐sectional study of 10 MS patients was performed using qMTI. A total of 60 MTI measurements were collected in each patient at a resolution of 2 × 2 × 7 mm, over a range of saturation pulses. The observed T1 and T2 were also measured. qMT model parameters were estimated using a voxel‐by‐voxel fit.ResultsA total of 65 T2‐hyperintense lesions were identified; 53 were also T1 hypointense. In these black holes, the qMTI‐derived semisolid pool fraction F correlated negatively with T1,obs (r2 = 0.76; P < 0.0001). The water pool absolute size (PDf) showed a weaker correlation with T1,obs (positive, r2 = 0.53; P < 0.0001). The magnetization transfer ratio (MTR) showed a similarly strong correlation with F and a weaker correlation with PDf (r2 = 0.18; P < 0.04).ConclusionT1 increases in chronic black holes strongly correlated with the decline in semisolid pool size, and somewhat less to the confounding effect of edema. MTR was less sensitive than T1,obs to liquid pool changes associated with edema. J. Magn. Reson. Imaging 2005;21:103–110. © 2005 Wiley‐Liss, Inc.
Coronary artery wall imaging: Initial experience at 3 Tesla
Authors: Koktzoglou Ioannis , Simonetti Orlando , Li Debiao 
Published: January 2005

AbstractPurposeTo assess the feasibility of black‐blood turbo spin‐echo imaging of the left anterior descending coronary artery wall at 3 Tesla under free‐breathing and breath‐hold conditions.Materials and MethodsProton density‐weighted black‐blood turbo spin‐echo imaging of the left anterior descending coronary artery was performed on 15 volunteers on a 3 T whole body scanner with an eight channel phased array coil. Volunteers were imaged during free‐breathing (with navigators, N = 5), or with breath‐hold (N = 5), or both (N = 2). Imaging was not possible in three volunteers due to either gradient or radiofrequency (RF) coupling with the electrocardiogram (ECG). Images were analyzed to determine coronary artery wall thickness, wall area, lumen diameter, and lumen area. Signal‐to‐noise and contrast‐to‐noise ratios were calculated.ResultsCoronary artery wall thickness, wall area, lumen diameter, and lumen area measurements were consistent with previous magnetic resonance (MR) measurements of the coronary wall at 1.5 Tesla.ConclusionCoronary wall imaging using free‐breathing and breath‐hold two‐dimensional black‐blood TSE is feasible at 3 T. Further improvement in resolution and image quality is required to detect and characterize coronary plaque. J. Magn. Reson. Imaging 2005;21:128–132. © 2005 Wiley‐Liss, Inc.
MR imaging of the normal appendix and acute appendicitis
Authors: Nitta Norihisa , Takahashi Masashi , Furukawa Akira , Murata Kiyoshi , Mori Masayuki , Fukushima Masanobu 
Published: January 2005

AbstractPurposeTo describe the MR appearance of the normal appendix and the MR imaging characteristics of acute appendicitis with correlation to pathological severity.Materials and MethodsA total of 20 volunteers participated in this study to demonstrate normal appendices by MR imaging. A total of 37 consecutive patients with clinically diagnosed acute appendicitis were also scanned. T1‐weighted (T1WI) spin‐echo images, T2‐weighted (T2WI) fast spin‐echo, and fat‐suppressed spectral presaturation inversion recovery T2‐weighted (T2SPIR) fast spin‐echo images were obtained. The MR criteria for considering acute appendicitis were as follows: 1) thickening of the appendiceal wall with high intensity on T2WI or T2SPIR; 2) dilated lumen filled with high intensity material on T2WI or T2SPIR; and 3) increased intensity of periappendiceal tissue on T2WI or T2SPIR.ResultsThe visibility of a normal appendix on MR imaging was 90% (18/20). It appeared as a cord‐like structure of medium intensity without fluid collection in the lumen. A total of 30 cases with clinically diagnosed acute appendicitis had positive MR findings and all except one were pathologically proven. The one had cecal diverticulitis. These cases demonstrated filled lumen, with a hypointense wall on T1WI and slightly hyperintense on T2WI or T2SPIR. MR findings correlated well with pathological severity, especially a thicker wall, periappendiceal high intensity, and ascites were useful for suspecting severe appendicitis.ConclusionCorrect diagnosis of acute appendicitis was obtained with MRI, and correlated well with its pathological severity. MRI is a powerful alternative for diagnosing acute appendicitis especially for the patients in whom the radiation is major concern. J. Magn. Reson. Imaging 2005;21:156–165. © 2005 Wiley‐Liss, Inc.
Myometrial invasion and cervical invasion by endometrial carcinoma: Evaluation by CO2‐volumetric interpolated breathhold examination (VIBE)
Authors: Akaeda Tomoyoshi , Isaka Keiichi , Takayama Masaomi , Kakizaki Dai , Abe Kimihiko 
Published: January 2005

AbstractPurposeTo assess myometrial invasion and cervical invasion by endometrial carcinoma, using CO2‐volumetric interpolated breathhold examination (VIBE) enabling more precise evaluation of depth of tumor invasion.Materials and MethodsCO2‐VIBE was performed in 21 cases of endometrial carcinoma (Stage Ia–IIb) prior to treatment. The images were interpreted by performing multiplanar reconstruction (MPR), and the findings obtained from the images (degree of myometrial invasion and presence or absence of cervical invasion) were assessed in comparison with the histopathological diagnosis.ResultsThe sites of the endometrial carcinoma lesions were clearly visualized by the CO2‐VIBE method. Evaluation of the degree of myometrial invasion enabled a high correct diagnosis rate of 90.5%, and evaluation for the presence of cervical invasion also allowed a high correct diagnosis rate of 90.5%.ConclusionVIBE permits evaluation of any plane desired by means of thin slices, and it is a truly revolutionary method for preoperative evaluation of depth of invasion of endometrial carcinoma that enables highly accurate determination of the extent of lesion sites and degree of invasion before treatment. J. Magn. Reson. Imaging 2005;21:166–171. © 2005 Wiley‐Liss, Inc.
Correlation of R2 with total iron concentration in the brains of rhesus monkeys
Authors: Hardy Peter A. , Gash Don , Yokel Robert , Andersen Anders , Ai Yi , Zhang Zhiming 
Published: January 2005

AbstractPurposeTo estimate the relationship between R2 = 1/T2 as measured with a double echo spin echo sequence and total iron concentration in gray matter structures in the brains of aging rhesus monkeys.Materials and MethodsUsing a 1.5‐T magnetic resonance (MR) imager, we collected double echo spin echo images of the brains of 12 female rhesus monkeys aged between 9 and 23 years. From the double echo images, the transverse relaxation rate R2 = 1/T2 was calculated in selected gray matter regions. After the animals were euthanized, their brains were excised and tissue punches were taken of the substantia nigra, globus pallidus, and gray matter regions of the cerebellum. Some of the tissue punches were assayed for total iron using atomic absorption spectroscopy.ResultsThe range of tissue iron concentration spanned from 15 to 450 μg/g wet weight, with the highest levels in the globus pallidus and the lowest levels in the cerebellum. The results show that R2 was highly correlated with the total iron concentration and that the relationship between R2 and tissue iron concentration appeared to depend upon the iron concentration. For concentrations above approximately 150 μg/g wet weight, R2 increased with a sensitivity of 0.0484 ± 0.0023 second−1(μg/g)−1. In contrast, where the iron concentration was below 150 μg/g, R2 increased at 0.0013 ± 0.0073 second−1(μg/g)−1. The bilinear behavior may reflect changes with age in the relative amounts of iron distributed diffusely and in granular form in the globus pallidus and substantia nigra. Histological sections of the tissues stained for iron and ferritin support this hypothesis and indicate that the distribution of ferritin is similar to the distribution of iron.ConclusionThis study reaffirms the value of measuring the MR relaxation rate R2 for a noninvasive estimate of iron content in the brain and identified limitations in the relationship at low tissue iron concentrations. J. Magn. Reson. Imaging 2005;21:118–127. © 2005 Wiley‐Liss, Inc.
Central brightening due to constructive interference with, without, and despite dielectric resonance
Authors: Collins Christopher M. , Liu Wanzhan , Schreiber Weston , Yang Qing X. , Smith Michael B. 
Published: January 2005

AbstractPurposeTo aid in discussion about the mechanism for central brightening in high field magnetic resonance imaging (MRI), especially regarding the appropriateness of using the term dielectric resonance to describe the central brightening seen in images of the human head.Materials and MethodsWe present both numerical calculations and experimental images at 3 T of a 35‐cm‐diameter spherical phantom of varying salinity both with one surface coil and with two surface coils on opposite sides, and further numerical calculations at frequencies corresponding to dielectric resonances for the sphere.ResultsWith two strategically placed surface coils it is possible to create central brightening even when one coil alone excites an image intensity pattern either bright on one side only or bright on both sides with central darkening. This central brightening can be created with strategic coil placement even when the resonant pattern would favor central darkening. Results in a conductive sample show that central brightening can similarly be achieved in weakly conductive dielectric materials where any true resonances would be heavily damped, such as in human tissues.ConclusionConstructive interference and wavelength effects are likely bigger contributors to central brightening in MR images of weakly conductive biological samples than is true dielectric resonance. J. Magn. Reson. Imaging 2005;21:192–196. © 2005 Wiley‐Liss, Inc.
A modified projection reconstruction trajectory for reduction of undersampling artifacts
Authors: Wang Wen‐Tung , Grimm Roger C. , Riederer Stephen J. 
Published: January 2005

AbstractPurposeTo reduce undersampling artifacts for a given number of repetitions of the projection reconstruction (PR) sequence by modifying its k‐space trajectory to sample more mid‐frequencies while reducing the sampling coverage of the peripheral spatial frequencies.Materials and MethodsThe single k‐space spoke measured per repetition in the standard PR was modified so that one complete and two partial spokes were measured per repetition but with decreased k‐space extent. The point spread functions (PSFs) and undersampling artifacts of the modified PR were compared with those of the standard PR for various numbers of projections. Phantom and in vivo images were used to assess the relative performance.ResultsPSF analysis indicated that the modified PR method provided reduced undersampling artifacts with somewhat reduced spatial resolution. The phantom and in vivo images corroborated this.ConclusionThe modified PR trajectory provides reduced undersampling artifact vs. the standard PR, particularly when the number of projections is limited and the artifact level is high. J. Magn. Reson. Imaging 2005;21:179–186. © 2005 Wiley‐Liss, Inc.
Interstudy reproducibility of three‐dimensional volume‐selective fast spin echo magnetic resonance for quantifying carotid artery wall volume
Authors: Varghese Anitha , Crowe Lindsey A. , Mohiaddin Raad H. , Gatehouse Peter D. , Yang Guang Zhong , Nott David M. , McCall James M. , Firmin David N. , Pennell Dudley J. 
Published: January 2005

AbstractPurposeTo assess the interstudy reproducibility of a three‐dimensional volume‐selective, fast spin echo (FSE) magnetic resonance technique for the assessment of carotid artery wall volume, which is a marker for total carotid plaque volume.Materials and MethodsInterstudy reproducibility was evaluated in 10 subjects with evidence of carotid artery atherosclerotic disease on carotid Doppler ultrasonography. Subjects were scanned twice with an interscan time of one hour to four days. The carotid artery was imaged in cross‐section, and the total carotid arterial wall volume (TWV) was calculated by subtraction of the total carotid lumen volume from the total outer carotid vessel volume.ResultsThe mean carotid TWV for the scans was 741 and 734 mm3, respectively, with no significant difference (mean difference 7 mm3; P = 0.5). The time for each study was approximately 20 minutes. The standard deviation of the differences between the measurements was 33 mm3, yielding an interstudy coefficient of variation of 4.4%. Sample size calculations showed that 16 patients would enable this difference in plaque volume over time to be detected with 80% power at a P value of 0.05.ConclusionVolumetric analysis with CMR of carotid artery plaques using a three‐dimensional volume‐selective FSE is efficient with good interstudy reproducibility, and is well suited for longitudinal studies of progression of carotid atheroma with reasonable sample sizes. J. Magn. Reson. Imaging 2005;21:187–191. © 2005 Wiley‐Liss, Inc.
Coronary arteries at 3.0 T: Contrast‐enhanced magnetization‐prepared three‐dimensional breathhold MR angiography
Authors: Bi Xiaoming , Li Debiao 
Published: January 2005

AbstractPurposeTo evaluate the efficacy of contrast‐enhanced coronary magnetic resonance angiography (MRA) at 3.0 T.Materials and MethodsNine healthy human volunteers were studied on a 3.0‐T whole‐body MR system. A three‐dimensional, breathhold, magnetization‐prepared, segmented, gradient‐echo sequence was used, with injection of 20 mL gadopentetate dimeglumine for each three‐dimensional slab. Imaging parameters were optimized based on computer simulations. Signal‐to‐noise ratio (SNR), contrast‐to‐noise ratio (CNR), depicted coronary artery length, lumen diameter, and imaging sharpness with contrast agent were evaluated. SNR and CNR were compared to the results from a previous 1.5‐T study.ResultsA 53% increment in SNR and a 305% enhancement in CNR were measured with contrast. Vessel length and sharpness depicted were higher and the lumen diameter was lower (all P values < 0.05) in postcontrast images. Compared to previous results from 1.5‐T, the SNR, CNR, and vessel sharpness were enhanced at 3.0 T with higher spatial resolution.ConclusionContrast‐enhanced, three‐dimensional, coronary MRA at 3.0 T is a promising technique for diagnosing coronary artery diseases. Patient studies are necessary to evaluate its clinical utility. J. Magn. Reson. Imaging 2005;21:133–139. © 2005 Wiley‐Liss, Inc.
The comparison of detailed chemical kinetic mechanisms; forward versus reverse rates with CHEMRev
Authors: Rolland Sébastien , Simmie John M. 
Published: January 2005

AbstractThe computation of the reverse rate of an elementary reaction given the forward rate and requisite thermodynamic data is well established. Nevertheless the procedure is extremely laborious and error prone, in particular, when large numbers of such calculations must be performed and the results fitted to traditional or extended forms of the Arrhenius rate constant equation. We have developed a software application, CHEMRev, which automatically performs such computations for Chemkin‐style reaction mechanisms. © 2005 Wiley Periodicals, Inc. Int J Chem Kinet 37: 119–125, 2005
Kinetic studies of the reactions of pentacyanoferrate(III) complexes with L‐ascorbic acid
Authors: Lin Lu‐Ming , Lien Ming‐Huei , Yeh Andrew 
Published: January 2005

AbstractThe reduction of Fe(CN)5L2− (L = pyridine, isonicotinamide, 4,4′‐bipyridine) complexes by ascorbic acid has been subjected to a detailed kinetic study in the range of pH 1–7.5. The rate law of the reaction is interpreted as a rate determining reaction between Fe(III) complexes and the ascorbic acid in the form of H2A(k0), HA−(k1), and A2− (k2), depending on the pH of the solution, followed by a rapid scavenge of the ascorbic acid radicals by Fe(III) complex. With given Ka1 and Ka2, the rate constants are k0 = 1.8, 7.0, and 4.4 M−1 s−1; k1 = 2.4 × 103, 5.8 × 103, and 5.3 × 103 M−1 s−1; k2 = 6.5 × 108, 8.8 × 108, and 7.9 × 108 M−1 s−1 for L = py, isn, and bpy, respectively, at μ = 0.10 M HClO4/LiClO4, T = 25°C. The kinetic results are compatible with the Marcus prediction. © 2005 Wiley Periodicals, Inc. Int J Chem Kinet 37: 126–133, 2005
Photophysics and kinetics of naphthopyran derivatives, part 1: General analytical solutions for the kinetics of AB(k,ϕ) and ABC(k,ϕ) systems
Authors: Maafi Mounir , Brown Robert G. 
Published: January 2005

AbstractA new formalism allowing solution of the differential equations for kinetic systems comprising three species (ABC) linked by first‐order thermal and/or photochemical reactions is proposed. The approach is developed specifically with photochromic materials in mind, but the formalism developed is shown to be applicable to a variety of kinetic systems irradiated with monochromatic light where the photokinetic factor (F) is constant. © 2005 Wiley Periodicals, Inc. Int J Chem Kinet 37: 162–174, 2005
Autopoisoning reactions over rough surface: A multifractal scaling analysis
Authors: Chaudhari Ajay , Yan Ching‐Cher Sanders , Lee Shyi‐Long 
Published: January 2005

AbstractThe effect of surface roughness and number of reaction event on the decay type diffusion limited reaction (DLR) over rough surface of random deposition model was studied to examine the surface morphological effect on the surface reaction. Effect of decay profiles on the reaction probability distribution (RPD) of the reaction was then analyzed with multifractal scaling techniques. The dynamics of these autopoisoning reactions is controlled by the two parameters, namely, the initial sticking probability (Pini) of every site and the decay rate (m). More the rough surface, less are the number of active sites and wider is the distribution of reaction probability. More the number of reaction events, more are the number of active sites and more is the homogeneity in the RPD. The q‐τ(q) multifractal curves are found to be nonlinear for all the cases which give wide range of α values in α‐f(α) multifractal spectrum. Smaller the decay rate, narrower is the range of α values. © 2005 Wiley Periodicals, Inc. Int J Chem Kinet 37: 175–182, 2005
Rate constants for the gas‐phase reactions of O3with a series of cycloalkenes at 296 ± 2 K
Authors: Cusick Roland D. , Atkinson Roger 
Published: January 2005

AbstractUsing a relative rate method, rate constants for the gas phase reactions of O3with 1‐ and 3‐methylcyclopentene, 1‐, 3‐, and 4‐methylcyclohexene, 1‐methylcycloheptene,cis‐cyclooctene, 1‐ and 3‐methylcyclooctene, 1,3‐ and 1,5‐cyclooctadiene, and 1,3,5,7‐cyclooctatetraene have been measured at 296 ± 2 K and atmospheric pressure of air. The rate constants obtained (in units of 10−18cm3molecule−1s−1) are 1‐methylcyclopentene, 832 ± 24; 3‐methylcyclopentene, 334 ± 12; 1‐methylcyclohexene, 146 ± 10; 3‐methylcyclohexene, 55.3 ± 2.6; 4‐methylcyclohexene, 73.1 ± 3.6; 1‐methylcycloheptene, 930 ± 24;cis‐cyclooctene, 386 ± 23; 1‐methylcyclooctene, 1420 ± 100; 3‐methylcyclooctene, 139 ± 9;cis,cis‐1,3‐cyclooctadiene, 20.0 ± 1.4; 1,5‐cyclooctadiene, 152 ± 10; and 1,3,5,7‐cyclooctatetraene, 2.60 ± 0.19, where the indicated errors are two least‐squares standard deviations and do not include the uncertainties in the rate constants for the reference alkenes (propene, 1‐butene,cis‐2‐butene,trans‐2‐butene, 2‐methyl‐2‐butene, and terpinolene). These rate data are compared with the few available literature data, and the effects of methyl substitution discussed. © 2005 Wiley Periodicals, Inc. Int J Chem Kinet 37: 183–190, 2005