A5014372104- Advanced MRI Techniques and Applications
- Cardiac Imaging and Diagnostics
- Cardiac Valve Diseases and Treatments
- Ultrasound and Hyperthermia Applications
- Tissue Engineering and Regenerative Medicine
- Viral Infections and Immunology Research
- Cardiomyopathy and Myosin Studies
- Ultrasound Imaging and Elastography
- Cardiac Arrhythmias and Treatments
- MRI in cancer diagnosis
- Renal and Vascular Pathologies
- Aortic Disease and Treatment Approaches
- Cerebrovascular and Carotid Artery Diseases
- Photoacoustic and Ultrasonic Imaging
- Advanced Electron Microscopy Techniques and Applications
- Electrostatic Discharge in Electronics
- Plasma Applications and Diagnostics
- Electrical and Bioimpedance Tomography
- Mesenchymal stem cell research
- Electrospun Nanofibers in Biomedical Applications
- Cannabis and Cannabinoid Research
- Thermoregulation and physiological responses
- Microbial Inactivation Methods
- Diabetes Management and Research
- Aortic aneurysm repair treatments
Vasoptic Medical (United States)
2024
Johns Hopkins University
2004-2023
Training Programs in Epidemiology and Public Health Interventions Network
2015
Johns Hopkins Medicine
2004-2008
National Heart Lung and Blood Institute
2005-2007
National Institutes of Health
2006-2007
University of Wisconsin–Madison
2006
Abstract Aims Pulsed field ablation (PFA) is a non-thermal ablative approach in which cardiomyocyte death obtained through irreversible electroporation (IRE). Data correlating the biophysical characteristics of IRE and lesion are limited. The aim this study was to assess effect different procedural parameters [voltage, number cycles (NoCs), contact] on vegetal animal model for IRE. Methods results Two hundred four Russet potatoes were used. lesions delivered 3 cm cored potato specimens using...
Purpose The presence of implanted electronic devices with conducting leads and electrodes are contraindicated for magnetic resonance imaging (MRI), denying many patients its potential benefits. prime concern is MRI's radio frequency (RF) fields, which can cause elevated local specific absorption rates (SARs) heat injury. purpose this article to develop compare a range passive implantable “MRI‐safe” lead designs. Methods Conducting incorporating different lengths (3–75 cm), insulation...
Abstract There is growing interest in delivering cellular agents to infarcted myocardium prevent postinfarction left ventricular remodeling. MRI can be effectively used differentiate from healthy myocardium. MR‐guided delivery of agents/therapeutics appealing because the therapeutics precisely targeted desired location within infarct. In this study, a steerable intramyocardial injection catheter that actively tracked under was developed and tested. The components were arranged form loopless...
Performing interventions using long conducting wires in MRI introduces the risk of focal RF heating at wire tip. Comprehensive EM simulations are combined with carefully measured experimental data to show that method-of-moments field modeling coupled heat transfer can adequately predict partially inserted into patient-mimicking phantom. The effects total length, position phantom, phantom scanner, and size examined. Increasing shift a wire's length maximum tip from about half wave toward...
Abstract Purpose To develop and test a novel interactive real‐time MRI environment that facilitates image‐guided cardiovascular interventions. Materials Methods Color highlighting of device‐mounted receiver coils, accelerated imaging multiple slices, adaptive projection modes, live three‐dimensional (3D) renderings other features were utilized to enhance navigation devices targeting tissue. Results Images are shown from several catheter‐based interventional procedures performed in swine...
Endovascular recanalization (guidewire traversal) of peripheral artery chronic total occlusion (CTO) can be challenging. X-ray angiography resolves CTO poorly. Virtually "blind" device advancement during x-ray-guided interventions lead to procedure failure, perforation, and hemorrhage. Alternatively, MRI may delineate the within occluded segment enhance procedural safety success. We hypothesized that real-time (rtMRI)-guided accomplished in an animal model.
Abstract Cardiac perforation during atrial septal puncture (ASP) might be avoided by improved image guidance. X‐ray fluoroscopy (XRF), which guides ASP, visualizes tissue poorly and does not convey depth information. Ultrasound is limited device shadows constrained imaging windows. Alternatively, real‐time MRI (rtMRI) provides excellent contrast in any orientation may enable ASP balloon septostomy (BAS) swine. Custom catheters incorporated “active” (receiver antenna) “passive” (iron or...
Diagnostic yield of endomyocardial biopsy is low, particularly in disease that affects the myocardium a nonuniform distribution. The authors hypothesized real-time MRI guidance could improve through targeted focal myocardial pathology. They tested this hypothesis an animal model pathology using intracoronary ethanol and microspheres. compared MRI-guided swine custom actively visualized bioptome against x-ray–guided commercial by skilled operators. Real-time significantly increased diagnostic biopsy.
To test the feasibility of performing magnetic resonance (MR)-guided trans-septal punctures in swine heart.All procedures were performed a 1.5-T MR scanner. A novel, active intravascular needle system was utilized for tracking and septal punctures. Trans-septal five using electrocardiogram (ECG)-gated high resolution non-ECG-gated, real-time imaging techniques. The advanced over guidewire from femoral vein. Once proper position, made.Active traversing septum possible. location catheter tip...
Purpose: To determine if, with use of magnetic resonance (MR) imaging guidance alone, transcaval puncture the superior mesenteric vein (SMV) and/or portal is feasible a percutaneous femoral approach. Materials and Methods: The Institutional Animal Care Use Committee approved animal studies. Ten inferior vena cava (IVC)–SMV punctures were performed in six pigs. An active MR intravascular needle system was used for all transvascular punctures, procedures 1.5-T unit. introduced via 12-F sheath...
Abstract The purpose of this study was to develop a standard 0.014‐inch intravascular magnetic resonance imaging guidewire (MRIG), coaxial cable with an extension the inner conductor, specifically designed for use in small vessels. After theoretical analysis, MRIG built by plating/cladding highly electrically conductive materials, silver or gold, over inside and outside conductors. conductors were made superelastic, nonmagnetic, biocompatible Nitinol MP35N. Then, comparison previously...
Abstract Purpose To validate the feasibility of using a newly designed MR imaging‐guidewire (MRIG) to guide angioplasty balloon placement in coronary arteries. Materials and Methods A custom gold/sliver/Nitinol/MP35N‐based, 0.014‐inch MRIG was manufactured. test its mechanical performance we used new catheterize left arteries three dogs under x‐ray fluoroscopy. further generate intracoronary imaging, positioned MRIG, along with dilation‐perfusion catheter, into an additional dogs....
Intraoperative monitoring of blood flow (BF) remains vital to guiding surgical decisions. Here, we report the use SurgeON™ Blood Flow Monitor (BFM), a prototype system that attaches microscopes and implements laser speckle contrast imaging (LSCI) noninvasively obtain present vascular BF information in real-time within microscope's eyepiece.
: The principal limitations of percutaneous techniques to replace the aortic valve are detailed visualization and durable prostheses. We report feasibility using real-time magnetic resonance imaging (MRI) provide precise anatomic detail visual feedback implant a proven bioprosthesis.: Twelve domestic pigs were anesthetized, and, through minimally invasive approach MRI guidance, underwent replacement. This was accomplished on beating heart by commercially available bioprosthesis. used...
Abstract Previous studies have confirmed the possibility of using an intravascular MR imaging guidewire (MRIG) as a heating source to enhance vascular gene transfection/expression. This motivated us develop new system that can perform imaging, radiofrequncy (RF) heating, and temperature monitoring simultaneously in scanner. To validate this concept, series mathematical simulations RF power loss along 0.032‐inch MRIG energy spatial distribution were performed determine optimum frequency....
Abstract Purpose To determine and track the planar orientation of active interventional devices without using localizing RF microcoils. Materials Methods An image‐based tracking method that determines a device's projection images was developed. automated manual detection scheme were implemented. The demonstrated in an vivo mesocaval puncture procedure swine, which required accurate transvascular needle catheter. Results plane catheter determined two images. scan adjusted automatically to...
Objective . Atherosclerosis is a leading cause of mortality and morbidity. Optical endoscopy, ultrasound, X-ray offer minimally invasive imaging assessments but have limited sensitivity for characterizing disease therapeutic response. Magnetic resonance (MRI) endoscopy newer idea employing tiny catheter-mounted detectors connected to the MRI scanner. It can see through vessel walls provide soft-tissue sensitivity, its slow speed limits practical applications. Our goal high-resolution with...
Purpose To develop and test in animal studies ex vivo vivo, an intravascular (IV) MRI‐guided high‐intensity focused ultrasound (HIFU) ablation method for targeting perivascular pathology with minimal injury to the vessel wall. Methods IV‐MRI antennas were combined 2‐ 4‐mm diameter water‐cooled IV‐ultrasound catheters on a 3T clinical MRI scanner. A software interface was developed monitoring thermal dose real‐time thermometry, protocol by repeat testing muscle liver tissue vivo. measured as...
Background Catheter-based transmyocardial injection offers a minimally invasive method to deliver therapeutics the heart. It is typically performed under X-ray fluoroscopic guidance, which suffers from poor demarcation of myocardial boundaries and an inability assess viability. MRI-guided intramyocardial delivery at 3T potential for more precise targeting these therapies with superior tissue contrast. Our group has been actively involved microencapsulated stem cell therapy improve retention...