379,899 research outputs found

    Triple-Modal Imaging of Magnetically-Targeted Nanocapsules in Solid Tumours In Vivo

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    Triple-modal imaging magnetic nanocapsules, encapsulating hydrophobic superparamagnetic iron oxide nanoparticles, are formulated and used to magnetically target solid tumours after intravenous administration in tumour-bearing mice. The engineered magnetic polymeric nanocapsules m-NCs are ~200 nm in size with negative Zeta potential and shown to be spherical in shape. The loading efficiency of superparamagnetic iron oxide nanoparticles in the m-NC was ~100%. Up to ~3- and ~2.2-fold increase in tumour uptake at 1 and 24 h was achieved, when a static magnetic field was applied to the tumour for 1 hour. m-NCs, with multiple imaging probes (e.g. indocyanine green, superparamagnetic iron oxide nanoparticles and indium-111), were capable of triple-modal imaging (fluorescence/magnetic resonance/nuclear imaging) in vivo. Using triple-modal imaging is to overcome the intrinsic limitations of single modality imaging and provides complementary information on the spatial distribution of the nanocarrier within the tumour. The significant findings of this study could open up new research perspectives in using novel magnetically-responsive nanomaterials in magnetic-drug targeting combined with multi-modal imaging

    Reliability of single-subject neural activation patterns in speech production tasks

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    Traditional group fMRI (functional magnetic resonance imaging) analyses are not designed to detect individual differences that may be crucial to better understanding speech disorders. Single-subject research could therefore provide a richer characterization of the neural substrates of speech production in development and disease. Before this line of research can be tackled, however, it is necessary to evaluate whether healthy individuals exhibit reproducible brain activation across multiple sessions during speech production tasks. In the present study, we evaluated the reliability and discriminability of cortical functional magnetic resonance imaging data from twenty neurotypical subjects who participated in two experiments involving reading aloud mono- or bisyllabic speech stimuli. Using traditional methods like the Dice and intraclass correlation coefficients, we found that most individuals displayed moderate to high reliability, with exceptions likely due to increased head motion in the scanner. Further, this level of reliability for speech production was not directly correlated with reliable patterns in the underlying average blood oxygenation level dependent signal across the brain. Finally, we found that a novel machine-learning subject classifier could identify these individuals by their speech activation patterns with 97% accuracy from among a dataset of seventy-five subjects. These results suggest that single-subject speech research would yield valid results and that investigations into the reliability of speech activation in people with speech disorders are warranted.Accepted manuscrip

    In vivo nuclear magnetic resonance imaging

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    During the past year the Woodlands Baylor Magnetic Resonance Imaging (MRI) facility became fully operational. A detailed description of this facility is given. One significant instrument addition this year was the 100 MHz, 40cm bore superconducting imaging spectrometer. This instrument gives researchers the capability to acquire high energy phosphate spectra. This will be used to investigate ATP, phosphocreatinine and inorganic phosphate changes in normal and atrophied muscle before, during and after exercise. An exercise device for use within the bore of the imaging magnet is under design/construction. The results of a study of T sub 1 and T sub 2 changes in atrophied muscle in animals and human subjects are given. The imaging and analysis of the lower leg of 15 research subjects before and after 5 weeks of complete bedrest was completed. A compilation of these results are attached


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    Recent years have seen the emergence of research applying functional neuroimaging to the study of cue-elicited drug craving. This research has begun to identify a distributed system of brain activity during drug craving. Functional magnetic resonance imaging (fMRI) was used to examine the effects of smoking expectancy on the neural response to neutral (e.g., roll of tape) and smoking-related (holding a cigarette) stimuli in male cigarette smokers deprived of nicotine for 8 hours. As predicted, several brain regions exhibited differential activation during cigarette versus neutral cue exposure. Moreover, instructions about smoking opportunity affected cue-elicited activation in several regions. These results highlight the importance of perceived drug availability in the neurobiological response to drug cues

    Autism and Research Using Magnetic Resonance Imaging

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    This qualitative study explored the experience of participating in a research study using magnetic resonance imaging (MRI) for children with autism spectrum disorder (ASD), typically developing (TYP) children, and their parent. It also assessed the feasibility, efficacy, and acceptability of the Going to MRI for a Research Study© iPad application (app), developed by the primary author, available for use for MRI preparation. The app provides a description of the steps of the MRI procedure, from the child’s perspective, outlining expected behaviors and responses. Ten English-speaking parent/child dyads (n = 20) participated in an audiotaped question guide-facilitated telephone interview about their experience in the MRI study. Participants confirmed the iPad app\u27s feasibility, efficacy, and acceptability. ASD child/parent themes differed from TYP child/parent themes. More children with ASD who used the app completed the MRI than without it. The iPad app may help children with ASD complete MRIs in future studies

    Effect of Lavender Essential Oil Inhalation on Anxiety Level for Patients Undergoing Closed Magnetic Resonance Imaging

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    Contents: Magnetic resonance imaging (MRI) is one of the medical diagnostic imaging techniques that can provoke or exaggerate anxiety in certain patients. It may sometimes lead to the cancelation of the MRI. The lavender essential oil has a long historical anxiolytic benefit. Aim: This study aimed to examine the effect of lavender essential oil inhalation with a massage on anxiety level for patients undergoing closed magnetic resonance imaging. Methods: A quasi-experimental research (study/control group) was used to achieve the aim of this study. The study was conducted at Magnetic Resonance Imaging Unit in Main University Hospital, Alexandria, Egypt. A convenient sample of 100 patients was divided into the study and control groups (50 patients for each). Two tools were used in the present study. Those were structured interview questionnaire that elicited the patients' sociodemographic characteristics, and State-Trait Anxiety Inventory to identify the patients’ anxiety levels. Results: There were no statistically significant differences between both groups concerning the anxiety level before the MRI procedure (χ2=2.041, P = 0.495). While there were statistically significant differences between both groups concerning anxiety level post-MRI procedure and after receiving interventions (χ2 =35.135, P=0.000), there was a highly statistically significant difference between anxiety levels before and after receiving intervention in study group patients (t= 77.059, P=0.000). Conclusion: Patients undergoing a closed magnetic resonance imaging who inhaled and massaged their hands with Lavender essential oil exhibited a reduced level of anxiety than the control group and compared to their preintervention level. The study recommended using the lavender essential oil, an inexpensive and noninvasive intervention in reducing MRI anxiety or other anxiety-producing procedures

    4D Lorentz Electron Microscopy Imaging: Magnetic Domain Wall Nucleation, Reversal, and Wave Velocity

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    Magnetization reversal is an important topic of research in the fields of both basic and applied ferromagnetism. For the study of magnetization reversal dynamics and magnetic domain wall (DW) motion in ferromagnetic thin films, imaging techniques are indispensable. Here, we report 4D imaging of DWs by the out-of-focus Fresnel method in Lorentz ultrafast electron microscopy (UEM), with in situ spatial and temporal resolutions. The temporal change in magnetization, as revealed by changes in image contrast, is clocked using an impulsive optical field to produce structural deformation of the specimen, thus modulating magnetic field components in the specimen plane. Directly visualized are DW nucleation and subsequent annihilation and oscillatory reappearance (periods of 32 and 45 ns) in nickel films on two different substrates. For the case of Ni films on a Ti/Si_(3)N_4 substrate, under conditions of minimum residual external magnetic field, the oscillation is associated with a unique traveling wave train of periodic magnetization reversal. The velocity of DW propagation in this wave train is measured to be 172 m/s with a wavelength of 7.8 μm. The success of this study demonstrates the promise of Lorentz UEM for real-space imaging of spin switching, ferromagnetic resonance, and laser-induced demagnetization in ferromagnetic nanostructures

    Identification of imaging selection patterns in acute ischemic stroke patients and the influence on treatment and clinical trial enrolment decision making

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    For the STroke Imaging Research (STIR) and VISTA-Imaging Investigators The purpose of this study was to collect precise information on the typical imaging decisions given specific clinical acute stroke scenarios. Stroke centers worldwide were surveyed regarding typical imaging used to work up representative acute stroke patients, make treatment decisions, and willingness to enroll in clinical trials. STroke Imaging Research and Virtual International Stroke Trials Archive-Imaging circulated an online survey of clinical case vignettes through its website, the websites of national professional societies from multiple countries as well as through email distribution lists from STroke Imaging Research and participating societies. Survey responders were asked to select the typical imaging work-up for each clinical vignette presented. Actual images were not presented to the survey responders. Instead, the survey then displayed several types of imaging findings offered by the imaging strategy, and the responders selected the appropriate therapy and whether to enroll into a clinical trial considering time from onset, clinical presentation, and imaging findings. A follow-up survey focusing on 6 h from onset was conducted after the release of the positive endovascular trials. We received 548 responses from 35 countries including 282 individual centers; 78% of the centers originating from Australia, Brazil, France, Germany, Spain, United Kingdom, and United States. The specific onset windows presented influenced the type of imaging work-up selected more than the clinical scenario. Magnetic Resonance Imaging usage (27-28%) was substantial, in particular for wake-up stroke. Following the release of the positive trials, selection of perfusion imaging significantly increased for imaging strategy. Usage of vascular or perfusion imaging by Computed Tomography or Magnetic Resonance Imaging beyond just parenchymal imaging was the primary work-up (62-87%) across all clinical vignettes and time windows. Perfusion imaging with Computed Tomography or Magnetic Resonance Imaging was associated with increased probability of enrollment into clinical trials for 0-3 h. Following the release of the positive endovascular trials, selection of endovascular only treatment for 6 h increased across all clinical vignettes