A5037494723- Characterization and Applications of Magnetic Nanoparticles
- Ultrasound Imaging and Elastography
- Advanced MRI Techniques and Applications
- Elasticity and Material Modeling
- Microfluidic and Bio-sensing Technologies
- Photoacoustic and Ultrasonic Imaging
- Image and Signal Denoising Methods
- Geomagnetism and Paleomagnetism Studies
- Ultrasonics and Acoustic Wave Propagation
- Medical Imaging Techniques and Applications
- Medical Image Segmentation Techniques
- Magnetic properties of thin films
- Advanced Neuroimaging Techniques and Applications
- Ultrasound and Hyperthermia Applications
- NMR spectroscopy and applications
- Nanoparticle-Based Drug Delivery
- Electrostatics and Colloid Interactions
- Advanced X-ray and CT Imaging
- Functional Brain Connectivity Studies
- Optical Imaging and Spectroscopy Techniques
- Pediatric Urology and Nephrology Studies
- MRI in cancer diagnosis
- Nuclear Physics and Applications
- Endometrial and Cervical Cancer Treatments
- Blood properties and coagulation
Dartmouth–Hitchcock Medical Center
2014-2025
Dartmouth College
2014-2025
Applied Nanotech (United States)
2025
Children's Hospital of Philadelphia
2023-2024
Sky Ridge Medical Center
2023
Pfizer (United States)
2021
St. Louis Children's Hospital
2018
Loyola University Chicago
2016-2018
Purdue University West Lafayette
2013-2018
Loyola University Medical Center
2016
Wavelet transforms are multiresolution decompositions that can be used to analyze signals and images. They describe a signal by the power at each scale position. Edges located very effectively in wavelet transform domain. A spatially selective noise filtration technique based on direct spatial correlation of several adjacent scales is introduced. high infer there significant feature position should passed through filter. The authors have tested simulated signals, phantom images, real MR It...
<b><i>Objective:</i></b> To assess patterns of regional brain activation in response to varying working memory loads shortly after mild traumatic injury (MTBI). <b><i>Background:</i></b> Many individuals complain difficulty MTBI. Memory performance these can be normal despite complaints. <b><i>Methods:</i></b> Brain a task (auditory n-back) were assessed with functional MRI 12 MTBI patients within 1 month their and 11 healthy control subjects. <b><i>Results:</i></b> differed between subjects...
We characterized the initiation and evolution of immune response against a new inducible p53-dependent model aggressive ovarian carcinoma that recapitulates leukocyte infiltrates cytokine milieu advanced human tumors. Unlike other models initiate tumors before development mature system, we detect measurable anti-tumor immunity from very early stages, which is driven by infiltrating dendritic cells (DCs) prevents steady tumor growth for prolonged periods. Coinciding with phenotypic switch in...
Abstract A new method of filtering MR images is presented that uses wavelet transforms instead Fourier transforms. The does not reduce the sharpness edges. However, eliminate any small structures are similar in size to noise eliminated. There many possible extensions filter. © 1991 Academic Press, Inc.
Magnetic resonance (MR)-guided near-infrared spectral tomography was developed and used to image adipose fibroglandular breast tissue of 11 normal female subjects, recruited under an institutional review board-approved protocol. Images hemoglobin, oxygen saturation, water fraction, subcellular scattering were reconstructed show that fractions both blood are higher than in tissue. Variation composition between individuals not significantly different across the scattered dense categories....
Abstract Purpose To describe initial in vivo experiences with a subzone‐based, steady‐state MR elastography (MRE) method. This sparse collection of results is intended to shed light on some the strengths and weaknesses existing clinical MRE approaches indicate important areas future research. Materials Methods Elastic property reconstruction are compared data compiled from limited body published studies breast elasticity. Mechanical parameter distributions also investigated terms their...
A finite element–based nonlinear inversion scheme for magnetic resonance (MR) elastography is detailed. The algorithm operates on small overlapping subzones of the total region interest, processed in a hierarchical order as determined by progressive error minimization. This zoned approach allows high degree spatial discretization, taking advantage data-rich environment afforded MR. technique tested simulation under high-noise conditions (15% random noise applied to displacement data) with...
The authors present a method of measuring the temperature magnetic nanoparticles that can be adapted to provide in vivo maps. Many minimally invasive therapies promise reduce health care costs and improve patient outcomes heat tissue very specific temperatures effective. Measurements are required because physiological cooling, primarily blood flow, makes difficult predict priori. ratio fifth third harmonics magnetization generated by sinusoidal field is used generate calibration curve...
A signal-to-noise ratio (SNR) measure based on the octahedral shear strain (the maximum in any plane for a 3D state of strain) is presented magnetic resonance elastography (MRE), where motion-based SNR measures are commonly used. The strain, γ, directly related to modulus, μ, through definition stress, τ = μγ. Therefore, noise important factor determining quality motion data, rather than motion. Motion and were found be correlated MRE gelatin phantoms human breast. Analysis stiffness...
Purpose: Nonlinear inversion (NLI) in MR elastography requires discretization of the displacement field for a finite element (FE) solution “forward problem”, and unknown mechanical property iterative “inverse problem”. The resolution requirements these two discretizations are different: forward problem sufficient FE mesh to ensure convergence, whereas lowering inverse stabilizes estimates presence measurement noise. Previous NLI implementations use same support fields, requiring trade‐off...
Superparamagnetic iron oxide nanoparticles with highly nonlinear magnetic behavior are attractive for biomedical applications like particle imaging and fluid hyperthermia. Such particles display interesting properties in alternating fields here we document experiments that show differences between the magnetization dynamics of certain frozen melted states. This effect goes beyond small temperature difference...
Superparamagnetic nanoparticles (SMNPs) with nonlinear magnetic behavior under alternating fields hold great potential in biomedical applications, including hyperthermia, biosensing, separation, particle imaging, etc. Magnetic hyperthermia therapy, based on the relaxation movement of SMNPs subjected to an field, is a promising modality for tumor treatment. Herein, we applied stochastic Langevin equation study performance by taking coupled Brownian–Néel rotations into account. The specific...
Fluid movement in the interstitial space of brain affects clearance waste products, which is an important factor pathophysiology dementia. Estimating fluid (ISF) flow critical to understanding these processes; yet, it has proven difficult measure non-invasively. The pulsatile component ISF may be particularly for clearance, e.g. by facilitating mixing. Directly measuring flows challenging due slow velocities and small volume fractions involved; however, present a unique opportunity as their...
Abstract Accurate characterization of harmonic tissue motion for realistic geometries and property distributions requires knowledge the full three‐dimensional displacement field because asymmetric nature both boundaries domain location internal mechanical heterogeneities. The implications this magnetic resonance elastography (MRE) are twofold. First, MRE methods which require measurement a within region interest, presence 3D effects reduces or eliminates possibility that simpler,...
An imaging system that simultaneously performs near infrared (NIR) tomography and magnetic resonance (MRI) is used to study breast tissue phantoms a healthy woman in vivo. NIR image reconstruction exploits the combined data set presented implements MR structure as soft-constraint property estimation. The algorithm incorporates spatially segmented regions into regularization matrix links locations with similar properties, applies Laplacian-type filter minimize variation within each region....
Impairment in semantic processing occurs early Alzheimer's disease (AD) and differential impact on subtypes of relations have been reported, yet there is little data the neuroanatomic basis these deficits. Patients with mild AD healthy controls underwent 3 functional MRI auditory stimulation tasks requiring or phonological decisions (match–mismatch) about word pairs (category–exemplar, category–function, pseudoword). showed a significant performance deficit only exemplar task. On voxel-based...
Results of recent functional magnetic resonance imaging (fMRI) studies memory are not entirely consistent with lesion studies. Furthermore, although probes have identified neural systems associated processing novel visual episodic information, auditory verbal using a novel/familiar paradigm has yet been examined. To address this gap, fMRI was used to compare the haemodynamic response when listening recently learned and words. Sixteen healthy adults (6 male, 10 female) 10-item word list 100%...
Experience suggests the existence of a connection between contrast gray-scale image and gradient magnitude intensity edges in neighborhood where is measured. This observation motivates development edge-based enhancement techniques. We present simple effective method for based on multiscale edge representation images. The an can be enhanced simply by stretching or upscaling maxima image. offers flexibility to selectively enhance features different sizes ability control noise magnification....
A multimodality instrument that integrated optical or near-infrared spectroscopy into a magnetic resonance imaging (MRI) breast coil was used to perform pilot study of image-guided on cancerous tissue. These results are believed be the first multiwavelength spectroscopic images cancer using MRI-guided constraints, and they show tumor have high hemoglobin water values, decreased oxygen saturation, increased subcellular granularity. The use frequency-domain diffuse tomography methods at many...
Magnetic resonance elastography (MRE) has been introduced in clinical practice as a possible surrogate for mechanical palpation, but its application to study the human brain vivo limited by low spatial resolution and complexity of inverse problem associated with biomechanical property estimation. Here, we report significant improvements MRE data acquisition reporting images high signal‐to‐noise ratio quantified octahedral shear strain metrics. Specifically, have developed sequence based on...