bluuebunny/crossref_metadata_2025_split huggingface dataset:
Laryngeal complications after lipoinjection for vocal fold augmentation
Authors: Sanderson J. Drew , Simpson C. Blake 
Published: June 2009

AbstractObjectives/Hypothesis:Vocal fold augmentation with autologous fat has been widely used for the last 15 years with varying success. Autologous fat is biocompatible, readily available, and easily harvested, making it a commonly used material for vocal fold augmentation. Although felt to be a relatively safe procedure, few studies have looked at the complication rate of lipoinjection for vocal fold augmentation.Study Design:Retrospective review.Methods:Ninety‐eight vocal fold injections were performed at one institution from 1997 to 2008. The charts were reviewed retrospectively, and age, diagnosis, side of procedure, concurrent procedures, length of follow‐up, and complications during or subsequent to the injection were recorded in a database. Patients were excluded if data was inadequate to make a determination regarding complication during or after lipoinjection.Results:Eighty‐eight patients met the criteria for review with an average age of 57.4 years. The most common indications for injection were vocal fold paresis, vocal fold scarring, and presbylaryngeus. Mean follow‐up was 20.2 months with a range of 0 months to 126 months. Overall, four laryngeal complications occurred (4.5%), including three over‐injections (3.4%) leading to poor voice quality and one granuloma formation (1.1%). The over‐injections were managed using cordotomy with fat removal, resulting in vocal improvement in all cases.Conclusions:Although lipoinjection vocal fold augmentation is a safe procedure, over‐injection of autologous fat is a risk. Lipoinjection for vocal fold augmentation can lead to over‐injection with dysphonia in a small number of patients. The complications can be managed with lateral cordotomy and fat removal.
Short‐duration accelerated breathing challenges affect phonation
Authors: Sivasankar Mahalakshmi , Erickson Elizabeth 
Published: June 2009

AbstractObjectives/Hypothesis:Inhaled air must be adequately humidified to prevent vocal fold drying, which is detrimental to phonation. The water content of inspired air is reduced by parameters, such as increased breathing rate and oral route. Accelerated oral breathing challenges induce airway dehydration and are posited to affect airway function. The primary objective of this study was to investigate whether accelerated oral breathing challenges are detrimental to phonation. The secondary objective of this study was to determine whether individuals at increased risk for developing voice problems (i.e., smokers) have greater adverse phonatory effects after accelerated breathing challenge than nonsmoking controls.Study Design:Prospective study with between‐subjects, repeated‐measures design.Methods:Female smokers (n = 12) and nonsmoking controls (n = 12) participated in this experimental study over 2 days that differed in ambient humidity. Phonation threshold pressures (PTP) were collected prior to and following short‐term accelerated and habitual breathing challenges. Respiratory measures were collected during the challenges.Results:Short‐term accelerated breathing challenges significantly increased PTP. This increase in PTP with accelerated breathing was transient and not significantly influenced by breathing route, ambient humidity, or smoking status. Likewise, respiratory measures were not affected by breathing route, ambient humidity, or smoking status.Conclusions:During daily activities, such as exercise, individuals may engage in accelerated breathing for prolonged durations. This study demonstrates that even extremely short durations of accelerated breathing may affect phonation.
Using cells devoid of RAS proteins as tools for drug discovery
Authors: Urosevic Jelena , Sum Eleanor Y.M. , Moneo Victoria , Drosten Matthias , Dhawahir Alma , Becerra Mercedes , Carnero Amancio , Barbacid Mariano 
Published: June 2009

AbstractMutational activation of RAS proteins occurs in nearly 30% of all human tumors. To date direct pharmacological inhibition of RAS oncoproteins has not been possible. As a consequence, current strategies are focusing on the development of inhibitors that target those kinases acting downstream of RAS proteins, including those of the RAF/MEK/ERK and PI3K/AKT pathways. Most of these inhibitors have undesired off‐target effects that mask the potential therapeutic effect of blocking their targeted kinases. To facilitate the screening of selective inhibitors, we have generated lines of mouse embryonic fibroblasts that lack endogenous Ras proteins. These cells proliferate due to ectopic expression of either Ras oncoproteins that selectively activate the Raf/Mek/Erk pathway such as H‐RasG12V/D38E or constitutively active kinases such as B‐Raf and Mek1. These cell lines were exposed to inhibitors against the RAF, MEK, and AKT kinases as well as inhibitors of other kinases known to crosstalk with RAS signaling such as JNK and p38. Amongst all compounds tested, only the MEK inhibitors U0126 and PD0325901, showed the expected specificity pattern. Yet, PD0325901, but not U0126, was able to inhibit a cell line lacking Ras proteins that owed its proliferative properties to loss of p53. Thus, suggesting unexpected off‐target activities for this compound. The use of cell lines whose proliferative properties exclusively depend on selective targets provide a novel strategy to analyze the specificity of selective inhibitors designed against molecular targets implicated in human cancer. © 2009 Wiley‐Liss, Inc.
Multinuclear magnetic resonance studies of fluoronitroanilines
Authors: Gierczyk Błażej , Nowak‐Wydra Barbara , Mielcarek Aleksandra , Zalas Maciej , Grajewski Jakub 
Published: June 2009

AbstractTen fluoronitroanilines have been synthesized and the 1H, 13C, 15N and, 19F NMR spectra of these compounds have been recorded and fully assigned. Density functional theory(DFT) calculations have been performed for all compounds studied. Experimental and theoretical results are compared and the structure and atom character influence on the accuracy of the calculation discussed. Copyright © 2009 John Wiley & Sons, Ltd.
Accuracy and precision of MR blood oximetry based on the long paramagnetic cylinder approximation of large vessels
Authors: Langham Michael C. , Magland Jeremy F. , Epstein Charles L. , Floyd Thomas F. , Wehrli Felix W. 
Published: June 2009

AbstractAn accurate noninvasive method to measure the hemoglobin oxygen saturation (%HbO2) of deep‐lying vessels without catheterization would have many clinical applications. Quantitative MRI may be the only imaging modality that can address this difficult and important problem. MR susceptometry–based oximetry for measuring blood oxygen saturation in large vessels models the vessel as a long paramagnetic cylinder immersed in an external field. The intravascular magnetic susceptibility relative to surrounding muscle tissue is a function of oxygenated hemoglobin (HbO2) and can be quantified with a field‐mapping pulse sequence. In this work, the method's accuracy and precision was investigated theoretically on the basis of an analytical expression for the arbitrarily oriented cylinder, as well as experimentally in phantoms and in vivo in the femoral artery and vein at 3T field strength. Errors resulting from vessel tilt, noncircularity of vessel cross‐section, and induced magnetic field gradients were evaluated and methods for correction were designed and implemented. Hemoglobin saturation was measured at successive vessel segments, differing in geometry, such as eccentricity and vessel tilt, but constant blood oxygen saturation levels, as a means to evaluate measurement consistency. The average standard error and coefficient of variation of measurements in phantoms were <2% with tilt correction alone, in agreement with theory, suggesting that high accuracy and reproducibility can be achieved while ignoring noncircularity for tilt angles up to about 30°. In vivo, repeated measurements of %HbO2 in the femoral vessels yielded a coefficient of variation of less than 5%. In conclusion, the data suggest that %HbO2 can be measured reproducibly in vivo in large vessels of the peripheral circulation on the basis of the paramagnetic cylinder approximation of the incremental field. Magn Reson Med, 2009. © 2009 Wiley‐Liss, Inc.
Profile order and time‐dependent artifacts in contrast‐enhanced coronary MR angiography at 3T: Origin and prevention
Authors: Kotys Melanie S. , Herzka Daniel A. , Vonken Evert‐Jan , Ohayon Jacques , Heroux Julie , Gharib Ahmed M. , Stuber Matthias , Pettigrew Roderic I. 
Published: June 2009

AbstractTo enhance the clinical value of coronary magnetic resonance angiography (MRA), high‐relaxivity contrast agents have recently been used at 3T. Here we examine a uniform bilateral shadowing artifact observed along the coronary arteries in MRA images collected using such a contrast agent. Simulations were performed to characterize this artifact, including its origin, to determine how best to mitigate this effect, and to optimize a data acquisition/injection scheme. An intraluminal contrast agent concentration model was used to simulate various acquisition strategies with two profile orders for a slow‐infusion of a high‐relaxivity contrast agent. Filtering effects from temporally variable weighting in k‐space are prominent when a centric, radial (CR) profile order is applied during contrast infusion, resulting in decreased signal enhancement and underestimation of vessel width, while both pre‐ and postinfusion steady‐state acquisitions result in overestimation of the vessel width. Acquisition during the brief postinfusion steady‐state produces the greatest signal enhancement and minimizes k‐space filtering artifacts. Magn Reson Med, 2009. © 2009 Wiley‐Liss, Inc.
In vivo measurement of ethanol metabolism in the rat liver using magnetic resonance spectroscopy of hyperpolarized [1‐13C]pyruvate
Authors: Spielman Daniel M. , Mayer Dirk , Yen Yi‐Fen , Tropp James , Hurd Ralph E. , Pfefferbaum Adolf 
Published: June 2009

Abstract[1‐13C]Pyruvate is a readily polarizable substrate that has been the subject of numerous magnetic resonance spectroscopy (MRS) studies of in vivo metabolism. In this work 13C‐MRS of hyperpolarized [1‐13C]pyruvate was used to interrogate a metabolic pathway involved in neither aerobic nor anaerobic metabolism. In particular, ethanol consumption leads to altered liver metabolism, which when excessive is associated with adverse medical conditions including fatty liver disease, hepatitis, cirrhosis, and cancer. Here we present a method for noninvasively monitoring this important process in vivo. Following the bolus injection of hyperpolarized [1‐13C]pyruvate, we demonstrate a significantly increased rat liver lactate production rate with the coadministration of ethanol (P = 0.0016 unpaired t‐test). The affect is attributable to increased liver nicotinamide adenine dinucleotide (NADH) associated with ethanol metabolism in combination with NADH's role as a coenzyme in pyruvate‐to‐lactate conversion. Beyond studies of liver metabolism, this novel in vivo assay of changes in NADH levels makes hyperpolarized [1‐13C]pyruvate a potentially viable substrate for studying the multiple in vivo metabolic pathways that use NADH (or NAD+) as a coenzyme, thus broadening the range of applications that have been discussed in the literature to date. Magn Reson Med, 2009. © 2009 Wiley‐Liss, Inc.
Fast functional brain imaging using constrained reconstruction based on regularization using arbitrary projections
Authors: Grotz Thimo , Zahneisen Benjamin , Ella Arsène , Zaitsev Maxim , Hennig Jürgen 
Published: June 2009

AbstractThis work describes a novel method for highly undersampled projection imaging using constrained reconstruction by Tikhonov‐Phillips regularization and its application for high temporal resolution functional MRI (fMRI) at a repetition time of 80 ms. The high‐resolution reference image used as in vivo coil sensitivity is acquired in a separate acquisition using otherwise identical parameters. Activation studies using a standard checkerboard activation paradigm demonstrate the inherent high sensitivity afforded by the possibility to separate activation‐related effects from “physiological noise.”. In this first proof‐of‐principle of the constrained reconstruction based on regularization using arbitrary projections (COBRA) technique, experiments are performed in a single‐slice mode, which allows for a comparison with fast single‐slice echo‐planar imaging (EPI) at equal temporal resolution. The COBRA method can be extended to three‐dimensional (3D) encoding without severe penalty in temporal performance. Analysis of the global signal change demonstrates the excellent reproducibility of COBRA compared to standard EPI. Activation analysis is considerably improved by the possibility to remove electrocardiogram (ECG)‐related and breathing‐related signal fluctuations by physiological correction of each individual breathing and ECG cycle, respectively. Magn Reson Med, 2009. © 2009 Wiley‐Liss, Inc.
Mouse lumbar and cervical spinal cord blood flow measurements by arterial spin labeling: Sensitivity optimization and first application
Authors: Duhamel Guillaume , Callot Virginie , Decherchi Patrick , Le Fur Yann , Marqueste Tanguy , Cozzone Patrick J. , Kober Frank 
Published: June 2009

AbstractIn spinal cord injuries (SCI), tissue edema and consequent ischemia play an important role in neuronal damage. The assessment of quantitative spinal cord blood flow (SCBF) would be very valuable to help in understanding SCI pathophysiology. SCBF has previously been measured in animals with invasive techniques such as hydrogen clearance or labeled microspheres. A recent preliminary study also demonstrated the feasibility of assessing cervical SCBF by MRI with arterial spin labeling (ASL). However, due to bulk motion and field inhomogeneities, the feasibility of perfusion MRI at lower levels of the SC (thoracic, lumbar) remained an open question. In the present study, absolute SCBF measurements were carried out at both the cervical C3 and lumbar L1 levels of mouse SC using an adapted presaturated flow‐sensitive alternating inversion recovery (presat‐FAIR) ASL technique at 11.75T. Quantitative SCBF maps (resolution of 133 × 133 μm2) showed significantly lower gray matter (GM) perfusion values at the L1 level as compared to the C3 level (6% and 11% for the ventral and dorsal horns and 8% for total GM). The presat‐FAIR technique was then successfully applied to a mouse model of hemisection performed at the L1 level, illustrating the potential of ASL to help in SC pathology characterization. Magn Reson Med, 2009. © 2009 Wiley‐Liss, Inc.
Robust correction of spike noise: Application to diffusion tensor imaging
Authors: Chavez S. , Storey P. , Graham S.J. 
Published: June 2009

AbstractEcho‐planar imaging (EPI) ‐based diffusion tensor imaging (DTI) is particularly prone to spike noise. However, existing spike noise correction methods are impractical for corrupted DTI data because the methods correct the complex MRI signal, which is not usually stored on clinical MRI systems. The present work describes a novel Outlier Detection De‐spiking technique (ODD) that consists of three steps: detection, localization, and correction. Using automated outlier detection schemes, ODD exploits the data redundancy available in DTI data sets that are acquired with a minimum of six different diffusion‐weighted images (DWIs) with similar signal and noise properties. A mathematical formulation, describing the effects of spike noise on magnitude images, yields appropriate measures for an outlier detection scheme used for spike detection while a normalization‐dependent outlier detection scheme is used for spike localization. ODD performs accurately on diverse DTI data sets corrupted by spike noise and can be used for automated control of DTI data quality. ODD can also be extended to other MRI applications with data redundancy, such as dynamic imaging and functional MRI. Magn Reson Med, 2009. © 2009 Wiley‐Liss, Inc.
Diffusion tensor imaging (DTI) of the brain in moving subjects: Application to in‐utero fetal and ex‐utero studies
Authors: Jiang Shuzhou , Xue Hui , Counsell Serena , Anjari Mustafa , Allsop Joanna , Rutherford Mary , Rueckert Daniel , Hajnal Joseph V. 
Published: June 2009

AbstractWe present a methodology to achieve 3D high‐resolution diffusion tensor image reconstruction of the brain in moving subjects. The source data is diffusion‐sensitized single‐shot echo‐planar images. After continuous scanning to acquire a repeated series of parallel slices with 15 diffusion directions, image registration is used to realign the images to correct for subject motion. Once aligned, the diffusion images are treated as irregularly‐sampled data where each voxel is associated with an appropriately rotated diffusion direction. This data is used to estimate the diffusion tensor on a regular grid. The method has been tested on data acquired at 1.5T from adults who deliberately moved and from eight fetuses imaged in utero. Maps of apparent diffusion coefficient (ADC) were reliably produced in all cases and promising performance was achieved for fractional anisotropy maps. Results from normal fetal brains were found to be consistent with published data from premature infants of similar gestational age. Magn Reson Med, 2009. © 2009 Wiley‐Liss, Inc.
Myocardial T mapping free of distortion using susceptibility‐weighted fast spin‐echo imaging: A feasibility study at 1.5 T and 3.0 T
Authors: Heinrichs Uwe , Utting Jane F. , Frauenrath Tobias , Hezel Fabian , Krombach Gabriele A. , Hodenius Michael A.J. , Kozerke Sebastian , Niendorf Thoralf 
Published: June 2009

AbstractThis study demonstrates the feasibility of applying free‐breathing, cardiac‐gated, susceptibility‐weighted fast spin‐echo imaging together with black blood preparation and navigator‐gated respiratory motion compensation for anatomically accurate T mapping of the heart. First, T maps are presented for oil phantoms without and with respiratory motion emulation (T = (22.1 ± 1.7) ms at 1.5 T and T = (22.65 ± 0.89) ms at 3.0 T). T relaxometry of a ferrofluid revealed relaxivities of R = (477.9 ± 17) mM−1s−1 and R = (449.6 ± 13) mM−1s−1 for UFLARE and multiecho gradient‐echo imaging at 1.5 T. For inferoseptal myocardial regions mean T values of 29.9 ± 6.6 ms (1.5 T) and 22.3 ± 4.8 ms (3.0 T) were estimated. For posterior myocardial areas close to the vena cava T‐values of 24.0 ± 6.4 ms (1.5 T) and 15.4 ± 1.8 ms (3.0 T) were observed. The merits and limitations of the proposed approach are discussed and its implications for cardiac and vascular T‐mapping are considered. Magn Reson Med, 2009. © 2009 Wiley‐Liss, Inc.
A respiratory self‐gating technique with 3D‐translation compensation for free‐breathing whole‐heart coronary MRA
Authors: Lai Peng , Bi Xiaoming , Jerecic Renate , Li Debiao 
Published: June 2009

AbstractRespiratory motion remains a major challenge for robust coronary MR angiography (MRA). Diaphragmatic navigator (NAV) suffers from indirect measurement of heart position. Respiratory self‐gating (RSG) approaches improve motion detection only in the head–feet direction, leaving motion in the other two dimensions unaccounted for. The purpose of this study was to extend conventional RSG (1D RSG) to RSG capable of 3D motion detection (3D RSG) by acquiring additional RSG projections with transverse‐motion‐encoding gradients. Simulation and volunteer studies were conducted to validate the effectiveness of this new method. Preliminary comparison was performed between coronary artery images reconstructed from the same datasets using different motion correction methods. Our simulation illustrates that a proper motion‐encoding gradient and derivation method enable accurate 3D motion detection. Results from whole‐heart coronary MRA show that 3D RSG can further reduce motion artifacts as compared to NAV and 1D RSG and enables use of larger gating windows for faster coronary imaging. Magn Reson Med, 2009. © 2009 Wiley‐Liss, Inc.
Quantitative spectroscopic imaging with in situ measurements of tissue water T1, T2, and density
Authors: Gasparovic C. , Neeb H. , Feis D.L. , Damaraju E. , Chen H. , Doty M.J. , South D.M. , Mullins P.G. , Bockholt H.J. , Shah N.J. 
Published: June 2009

AbstractThe use of tissue water as a concentration standard in proton magnetic resonance spectroscopy (1H‐MRS) of the brain requires that the water proton signal be adjusted for relaxation and partial volume effects. While single voxel 1H‐MRS studies have often included measurements of water proton T1, T2, and density based on additional 1H‐MRS acquisitions (e.g., at multiple echo or repetition times), this approach is not practical for 1H‐MRS imaging (1H‐MRSI). In this report we demonstrate a method for using in situ measurements of water T1, T2, and density to calculate metabolite concentrations from 1H‐MRSI data. The relaxation and density data are coregistered with the 1H‐MRSI data and provide detailed information on the water signal appropriate to the individual subject and tissue region. We present data from both healthy subjects and a subject with brain lesions, underscoring the importance of water parameter measurements on a subject‐by‐subject and voxel‐by‐voxel basis. Magn Reson Med, 2009. © 2009 Wiley‐Liss, Inc.
In vivo lactate signal enhancement using binomial spectral‐selective pulses in selective MQ coherence (SS‐SelMQC) spectroscopy
Authors: Thakur S.B. , Yaligar J. , Koutcher J.A. 
Published: June 2009

AbstractTumor vasculature and tissue oxygen pressure can influence tumor growth, metastases, and patient survival. Elevated levels of lactate may be observed during the process of aggressive tumor development accompanied by angiogenesis (the evolution of the microenvironment). The noninvasive MR detection of lactate in tumor tissues as a potential biomarker is difficult due to the presence of co‐resonating lipids that are present at high concentrations. Methods were previously reported for lactate editing using the SELective Multiple Quantum Coherence (SelMQC) method. Here we report a sequence “SS‐SelMQC,” Spectral‐Selective SelMQC, which is a modified version of SelMQC using binomial pulses. Binomial pulses were employed in this editing sequence for frequency excitation or inversion of selective lactate resonances. Lactate detection has been demonstrated using SS‐SelMQC, both in vitro (30 mM lactate/H2O doped with 25 μM Gd‐DTPA) and in vivo (Dunning R3337‐AT prostate tumors), and compared to similar measurements made with SelMQC. Lactate areas were measured from nonlocalized spectra, one‐dimensional (1D) localized spectra, and two‐dimensional chemical shift images (CSI) of the localized slice. In data from whole phantoms, the modified pulse sequence yielded enhancement of the lactate signal of 2.4 ± 0.40 times compared to SelMQC. Similar in vivo lactate signal enhancement of 2.3 ± 0.24 times was observed in 1D slice‐localized experiment. Magn Reson Med, 2009. © 2009 Wiley‐Liss, Inc.
Manganese‐guided cellular MRI of human embryonic stem cell and human bone marrow stromal cell viability
Authors: Yamada Mayumi , Gurney Paul T. , Chung Jaehoon , Kundu Pratima , Drukker Micha , Smith Alan K. , Weissman Irving L. , Nishimura Dwight , Robbins Robert C. , Yang Phillip C. 
Published: June 2009

AbstractThis study investigated the ability of MnCl2 as a cellular MRI contrast agent to determine the in vitro viability of human embryonic stem cells (hESC) and human bone marrow stromal cells (hBMSC). Basic MRI parameters including T1 and T2 values of MnCl2‐labeled hESC and hBMSC were measured and viability signal of manganese (Mn2+)‐labeled cells was validated. Furthermore, the biological activity of Ca2+‐channels was modulated utilizing both Ca2+‐channel agonist and antagonist to evaluate concomitant signal changes. Metabolic effects of MnCl2‐labeling were also assessed using assays for cell viability, proliferation, and apoptosis. Finally, in vivo Mn2+‐guided MRI of the transplanted hESC was successfully achieved and validated by bioluminescence imaging. Magn Reson Med, 2009. © 2009 Wiley‐Liss, Inc.