A5000311910- Advanced MRI Techniques and Applications
- MRI in cancer diagnosis
- Advanced Neuroimaging Techniques and Applications
- Muscle Physiology and Disorders
- Multiple Sclerosis Research Studies
- Malaria Research and Control
- Lanthanide and Transition Metal Complexes
- Medical Imaging Techniques and Applications
- Mosquito-borne diseases and control
- Muscle activation and electromyography studies
- Cerebrovascular and Carotid Artery Diseases
- Genetic Neurodegenerative Diseases
- Cardiomyopathy and Myosin Studies
- Advanced NMR Techniques and Applications
- Adipose Tissue and Metabolism
- Ultrasound Imaging and Elastography
- Systemic Lupus Erythematosus Research
- Neurological Disease Mechanisms and Treatments
- Cerebrospinal fluid and hydrocephalus
- Ultrasound and Hyperthermia Applications
- Birth, Development, and Health
- NMR spectroscopy and applications
- Glioma Diagnosis and Treatment
- Neuroscience and Neuropharmacology Research
- Functional Brain Connectivity Studies
Advanced Imaging Research (United States)
2015-2024
Oregon Health & Science University
2015-2024
University of Florida
2014-2022
Oregon Medical Research Center
2018-2022
University of California, Los Angeles
2022
Children's Hospital of Philadelphia
2013-2020
Nemours Children's Clinic
2020
Shriners Hospitals for Children - Portland
2018-2020
University of Portland
2018
University of Michigan–Ann Arbor
2018
Abstract Brain water proton ( 1 H 2 O) longitudinal relaxation time constants T ) were obtained from three healthy individuals at magnetic field strengths B 0 of 0.2 Tesla (T), 1.0T, 1.5T, 4.0T, and 7.0T. A 5‐mm midventricular axial slice was sampled using a modified Look‐Locker technique with 1.5 mm in‐plane resolution, 32 points post‐adiabatic inversion. The results confirmed that for most brain tissues, values increased by more than factor 3 between 0.2T 7T, over this range well fitted...
To compare MS normal-appearing white matter (NAWM) where new gadolinium-enhancing (Gd+) lesions do and not arise.A total of 22 relapsing-remitting patients 11 healthy control subjects completed as many 12 monthly brain MRI sessions. Quantitative measures gadolinium enhancement (GDR), water proton density (PDN), T2 relaxation time constants (T2), magnetization transfer ratio (MTR), T1-weighted signal intensity (T1N) were followed serially in NAWM.A 129 Gd+ identified patients. PDN, T2, MTR,...
For bolus-tracking studies, it is commonly assumed that CR concentration bears a linear relationship with the measured (usually longitudinal) 1H2O relaxation rate constant, R*1 ≡(T1 *)–1. This requires equilibrium transcytolemmal water exchange be in fast limit (FXL). However, though systems remain exchange, FXL will not usually obtain. Here, consequences are considered: 1) measurement of R1 * itself can affected, 2) resultant non-linear [CR]-dependence causes significant error by assuming...
Abstract Contrast reagents (CRs) may enter the tissue interstitium for a period after vascular bolus injection. As amount of interstitial CR increases, longitudinal relaxographic NMR “shutter‐speed” ( T –1 ) equilibrium transcytolemmal water exchange process increases. The quantity is given by |r 1o [CR o ] + R 1o0 – 1i | (where r and represent (extracellular) relaxivity concentration, respectively, are extra‐ intracellular 1 H 2 O relaxation rate constants, in absence exchange). increase...
Purpose To compare gadoteridol and ferumoxytol for measurement of relative cerebral blood volume (rCBV) in patients with glioblastoma multiforme (GBM) who showed progressive disease at conventional magnetic resonance (MR) imaging after chemo- radiation therapy (hereafter, chemoradiotherapy) to correlate rCBV survival. Materials Methods Informed consent was obtained from all participants before enrollment one four institutional review board–approved protocols. Contrast agent leakage maps were...
Objective The aim of this study was to describe Duchenne muscular dystrophy (DMD) disease progression in the lower extremity muscles over 12 months using quantitative magnetic resonance (MR) biomarkers, collected across three sites a large cohort. Methods A total 109 ambulatory boys with DMD (8.7 ± 2.0 years; range, 5.0–12.9) completed baseline and 1‐year follow‐up MR imaging (transverse relaxation time constant; MRI‐T 2 ), spectroscopy (fat fraction 1 H O T 6‐minute walk test (6MWT)...
To evaluate the effects of corticosteroids on lower extremity muscles in boys with Duchenne muscular dystrophy (DMD) using MRI and magnetic resonance spectroscopy (MRS).Transverse relaxation time (T2) fat fraction were measured by MRI/MRS 15 DMD (age 5.0-6.9 years) taking corticosteroid-naive boys. Subsequently, was a subset these at 1 year. Finally, data collected from 16 5-8.9 baseline, 3 months, 6 months. Five treated after baseline remaining 11 served as controls.Cross-sectional...
CT is considered the gold standard imaging modality for measurement of visceral adipose tissue area. However, as exposes subjects to ionising radiation, a comparable technique without this exposure desirable, such MRI. Therefore, we compared agreement measures and subcutaneous area from single-slice images obtained at umbilicus using 3 T MRI scanner with via scan.64 were 27 who underwent scanning on same day, after 10-12 hours fasting. Visceral depots manually separated quantified...
Purpose Magnetic resonance T 1 ‐weighted images are routinely used for human brain segmentation, parcellation, and clinical diagnosis of demyelinating diseases. Myelin is thought to influence the longitudinal relaxation commonly described by a mono‐exponential recovery, although reports bi‐exponential have been published. The purpose this work was investigate if myelin water contribution could be separated in geometrically sampled Look‐Locker trains low flip angle gradient echoes. Methods...
Introduction Duchenne muscular dystrophy (DMD) is an X-linked recessive disorder that results in functional deficits. However, these declines are often not able to be quantified clinical trials for DMD until after age 7. In this study, we hypothesized 1H2O T2 derived using 1H-MRS and MRI-T2 will sensitive muscle involvement at a young (5–7 years) consistent with increased inflammation damage large cohort of subjects compared controls. Methods MR data were acquired from 123 boys (ages 5–14...
White matter hyperintensities (WMHs) are common with age, grow over time, and associated cognitive motor impairments. Mechanisms underlying WMH growth unclear. We aimed to determine the presence extent of decreased normal appearing white (NAWM) cerebral blood flow (CBF) surrounding WMHs identify 'WM at risk', or CBF penumbra. further validate cross-sectional finding by determining whether baseline penumbra predicts development new follow-up. Sixty-one cognitively intact elderly subjects...
MR imaging can be used to measure structural changes in the brains of individuals with multiple sclerosis and is essential for diagnosis, longitudinal monitoring, therapy evaluation. The North American Imaging Multiple Sclerosis Cooperative steering committee developed a uniform high-resolution 3T protocol relevant quantification cerebral lesions atrophy implemented it at 7 sites across United States. To assess intersite variability scan data, we imaged volunteer relapsing-remitting MS...
Abstract Although multiple sclerosis has traditionally been considered a white matter disease, extensive research documents the presence and importance of grey injury including cortical deep regions. The exhibits broad range pathology is uniquely suited to study mechanisms clinical relevance tissue in using magnetic resonance techniques. Deep associated with cognitive disability. Recently, MRI characterization properties, such as thalamic volume, have tested potential trial end points...
For bolus-tracking studies, it is commonly assumed that CR concentration bears a linear relationship with the measured (usually longitudinal) (1)H(2)O relaxation rate constant, R*(1) identical with(T(1) *)(-1). This requires equilibrium transcytolemmal water exchange be in fast limit (FXL). However, though systems remain exchange, FXL will not usually obtain. Here, consequences are considered: 1) measurement of R(1) * itself can affected, 2) resultant non-linear [CR]-dependence causes...
Abstract An extensive protocol for the study of tissue resonances spin 3/2 nuclei is described. The roles most relevant multiple pulse experiments are indicated. Their theory organized in terms irreducible tensor operators and quadrupolar relaxation transfer functions which relate them a type c spectrum. A systematic approach to interpretation temperature and/or magnetic field dependences all six rate constants resonance single population isolated spins fast exchange, giving rise spectrum,...
Abstract A fundamental reworking of pharmacokinetic theory for the use contrast reagents (CRs) in T 1 ‐weighted MRI studies is presented. Unlike standard model common use, this derivation starts with quantities measured, intravascular, interstitial, and intracellular H 2 O signals. The time dependences CR concentrations are introduced as perturbations values these. Since there an explicit accounting equilibrium exchange water molecules between tissue compartments, approach here a new...
Malaria can be diagnosed either by direct microscopic examination of blood smears, which is time consuming and requires expertise, or immunological techniques, are effective but do not distinguish between past present infections. In this study, a simple procedure was developed for spotting lysed from infected patients directly onto nitrocellulose paper identifying the malaria species on basis hybridization parasite DNA with species-specific probe. A genomic library Plasmodium falciparum...
Cerebral blood volume (CBV) measurement complements conventional magnetic resonance imaging (MRI) to indicate pathologies in the central nervous system (CNS). Dynamic susceptibility contrast (DSC) perfusion is limited by low resolution and distortion. Steady-state (SS) may provide higher CBV maps but was not previously possible patients. We tested feasibility of clinical SS-CBV using ferumoxytol, a nanoparticle pool agent. analyzed at various ferumoxytol doses compared with DSC-CBV...
Purpose The relationship between fat fractions (FFs) determined based on multiple TE, unipolar gradient echo images and 1H magnetic resonance spectroscopy (MRS) was evaluated using different models for fat-water decomposition, signal-to-noise ratios, excitation flip angles. Methods A combination of single-voxel proton (1H-MRS) imaging used to determine muscle FFs in both normal dystrophic muscles. In order cover a large range FFs, the soleus vastus lateralis muscles 22 unaffected control...