A5049593207- Advanced MRI Techniques and Applications
- Ultrasound and Hyperthermia Applications
- Cerebrovascular and Carotid Artery Diseases
- MRI in cancer diagnosis
- Ultrasound Imaging and Elastography
- Photoacoustic and Ultrasonic Imaging
- Cardiac Imaging and Diagnostics
- Advanced Neuroimaging Techniques and Applications
- Medical Imaging Techniques and Applications
- Acute Ischemic Stroke Management
- Lanthanide and Transition Metal Complexes
- Cardiovascular Health and Disease Prevention
- Medical Image Segmentation Techniques
- Atomic and Subatomic Physics Research
- NMR spectroscopy and applications
- Intracranial Aneurysms: Treatment and Complications
- Advanced X-ray and CT Imaging
- Intracerebral and Subarachnoid Hemorrhage Research
- Atrial Fibrillation Management and Outcomes
- Traumatic Brain Injury and Neurovascular Disturbances
- Cardiac Arrhythmias and Treatments
- Coronary Interventions and Diagnostics
- Advanced NMR Techniques and Applications
- Ultrasonics and Acoustic Wave Propagation
- Infrared Thermography in Medicine
University of Utah
2016-2025
Wayne State University
2010-2025
Detroit Medical Center
2015-2025
Detroit Receiving Hospital
1999-2024
Eugene Applebaum College of Pharmacy and Health Sciences
2010-2024
DMS Imaging (France)
2024
Advanced Imaging Research (United States)
2014-2023
Ochsner Medical Center
2022
Duke Medical Center
2021
Johns Hopkins University
2021
Atrial fibrillation (AF) is associated with diffuse left atrial fibrosis and a reduction in endocardial voltage. These changes are indicators of AF severity appear to be predictors treatment outcome. In this study, we report the utility delayed-enhancement magnetic resonance imaging (DE-MRI) detecting abnormal tissue before radiofrequency ablation predicting procedural outcome.Eighty-one patients presenting for pulmonary vein antrum isolation underwent 3-dimensional DE-MRI atrium ablation....
Abstract The diffusion tensor is currently the accepted model of in biological tissues. measured behavior may be more complex when two or distinct tissues with different tensors occupy same voxel. In this study, a partial volume MRI signal for diffusion‐tensor compartments presented. Simulations using demonstrate that conventional single could lead to highly variable and inaccurate measurements behavior. differences between two‐tensor models depend on orientations, fractions, exchange...
The problem of using a divergent fan beam convolution reconstruction algorithm in conjunction with minimal complete (180° plus the angle) data set is reviewed. It shown that by proper weighting initial set, image quality essentially equivalent to reconstructions from 360° sets obtained. constraints on weights are sum two corresponding same line‐integral must equal one, regions no zero, and themselves as well gradient be continuous over full 360°. After satisfy these constraints, can...
Background— Although catheter ablation therapy for atrial fibrillation (AF) is becoming more common, results vary widely, and patient selection criteria remain poorly defined. We hypothesized that late gadolinium enhancement MRI (LGE-MRI) can identify left (LA) wall structural remodeling (SRM) stratify patients who are likely or not to benefit from therapy. Methods Results— LGE-MRI was performed on 426 consecutive with AF without contraindications before undergoing their first procedure 21...
This paper represents a preliminary study of the effects regional temperature distribution in two‐dimensional nuclear magnetic resonance (NMR) T 1 imaging. It is found, as expected, that variations local appear corresponding image. The potential use NMR imaging measurements evaluated case water and blood samples. Using containers where could be either known or directly controlled with reasonable accuracy, images are obtained samples having at least two regions different temperatures. As...
Abstract The accuracy of single diffusion tensor MRI (DT‐MRI) measurements depends upon the encoding scheme used. In this study, several strategies for DT‐MRI are compared. based heuristic, numerically optimized, and regular polyhedra schemes. criteria numerical optimization include minimum variance (MV), force (MF), potential energy (ME), condition number. includes variations icosahedron. Analytical comparisons Monte Carlo simulations show that icosahedron is optimum six directions. MV, MF,...
Abstract The accuracy of volume flow rate measurements obtained with phase‐contrast methods was assessed by means computer simulation and in vitro experiments. Factors studied include (a) the partial‐volume effect due to voxel dimensions relative vessel orientation (b) intravoxel phase dispersion. It is shown that limited resolution (partial‐volume effect) major obstacle accurate measurement for both laminar plug flow. results show at least 16 voxels must cover cross section lumen obtain a...
Abstract Multiple overlapping thin 3D slab acquisition is presented as a magnitude contrast (time of flight) technique which combines advantages from multiple slice 2D and direct volume acquisitions to obtain high‐resolution cross‐sectional images vessel detail. Details implementation example are presented. ©1991 Academic Press, Inc.
Abstract Partial‐volume artifacts reduce vessel contrast and continuity (especially in small vessels) magnetic resonance (MR angiography. The authors applied zero‐filled (band‐limited) interpolation to three‐dimensional (3D) MR angiograms partial‐volume artifacts. They demonstrated that can also be implemented by means of voxel shifting real space. Voxel‐shifted is much less computer memory intensive than conventional interpolation. numerically simulated the loss due recovery obtained with...
Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) is a widely used technique for assessing tissue physiology. Spoiled gradient echo (SPGR) pulse sequences are one of the most common methods acquisition DCE-MRI data, providing high temporal and spatial resolution with strong T1-weighting. Conversion SPGR signal to concentration briefly reviewed, new closed-form expression measurement uncertainty finite signal-to-noise ratio (SNR) baseline scan time derived. This result applicable...
Abstract A dark band or rim along parts of the subendocardial border left ventricle (LV) and myocardium has been noticed in some dynamic contrast‐enhanced MR perfusion studies. The artifact is thought to be due susceptibility effects from gadolinium bolus, motion, resolution, a combination these. Here motionless ex vivo hearts which cavity was filled with are used show that artifacts can consistent resolution alone. Magn Reson Med, 2005. © 2005 Wiley‐Liss, Inc.
The degree of diffusion tensor anisotropy is often associated with the organization structural tissues such as white matter. Numerous measures have been proposed, which could lead to confusion in interpreting and comparing results from different studies. In this study, a new method for representing shape, called three-phase (3P) plot, described. This graphical technique based upon barycentric coordinate system, weights shape by combination linear, cylindrical, spherical factors. system can...
Abstract Small gradient fields resulting from incompletely canceled eddy currents can cause geometric distortion in echo‐planar images. Although this is negligible most applications, the large pulses used diffusion‐weighted imaging result significant image distortion. In report, it shown that be significantly reduced by application of bipolar waveforms. Both diffusion‐sensitizing gradients and an inverted preparatory pulse were examined for minimizing responsible these distortions.
A tissue-mimicking phantom that accurately represents human-tissue properties is important for safety testing and validating new imaging techniques. To achieve a variety of desired properties, we have fabricated tested several variations gelatin phantoms. These phantoms are simple to manufacture in the same order magnitude as those soft tissues. This quality-assurance verification well validation magnetic resonance-guided focused ultrasound (MRgFUS) treatment techniques.The presented this...
Potential applications of three-dimensional nuclear magnetic resonance (NMR) imaging to noninvasive temperature monitoring as well tissue heating are discussed. Although heat delivery using conventional NMR is negligible, the physical basis for transfer reviewed and potential increase shown depend on both static field longitudinal relaxation time (T1)
Abstract A novel method for iterative reconstruction of images from undersampled MRI data acquired by multiple receiver coil systems is presented. Based on Projection onto Convex Sets (POCS) formalism, the SENSitivity Encoded (POCSENSE) can be readily modified to include various linear and nonlinear constraints. Such constraints may beneficial reconstructing highly overcritically sets improve image quality. POCSENSE conceptually simple numerically efficient reconstruct sampled arbitrary k...
Multiple overlapping thin slab acquisition (MOTSA) is a novel time-of-flight magnetic resonance (MR) angiography technique that combines many of the advantages multiple-section two-dimensional and direct three-dimensional volume methods. To rigorously evaluate vascular detail can be obtained with MOTSA MR angiography, authors have quantified frequency visibility intracranial arterial segments correlated their vessel size as measured at cut-film position orientation segment. Intracranial...