A5089224791- Advanced MRI Techniques and Applications
- Cardiac Imaging and Diagnostics
- Ultrasound and Hyperthermia Applications
- Atomic and Subatomic Physics Research
- Advanced NMR Techniques and Applications
- Ultrasound Imaging and Elastography
- Wireless Power Transfer Systems
- Prostate Cancer Diagnosis and Treatment
- Photoacoustic and Ultrasonic Imaging
- MRI in cancer diagnosis
- Neurological disorders and treatments
- Electron Spin Resonance Studies
- Cerebrovascular and Carotid Artery Diseases
- Medical Imaging Techniques and Applications
- Coronary Interventions and Diagnostics
- Cardiac Valve Diseases and Treatments
- NMR spectroscopy and applications
- Characterization and Applications of Magnetic Nanoparticles
- Advanced Radiotherapy Techniques
- Cardiovascular Function and Risk Factors
- Electrical and Bioimpedance Tomography
- Cardiac Arrhythmias and Treatments
- Neuroscience and Neural Engineering
- Advanced X-ray and CT Imaging
- Microwave Imaging and Scattering Analysis
Bilkent University
2015-2025
Memorial Ankara Hospital
2024
Resonance Research (United States)
2019-2020
Johns Hopkins University
2000-2010
Johns Hopkins Medicine
1999-2010
Princess Margaret Cancer Centre
2006
University of Toronto
2006
United States Department of Health and Human Services
2006
National Institutes of Health
1998-2006
National Heart Lung and Blood Institute
1998-2006
Guidelines and Expert Consensus Documents summarize evaluate all available evidence with the aim of assisting physicians in selecting best management strategy for an individual patient suffering from a given condition, taking into account impact on outcome risk–benefit ratio diagnostic or therapeutic means. are no substitutes textbooks their legal implications have been discussed previously. recommendations should help to make decisions daily practice. However, ultimate judgement regarding...
We investigated the potential of magnetic resonance imaging (MRI) to track magnetically labeled mesenchymal stem cells (MR-MSCs) in a swine myocardial infarction (MI) model.Adult farm pigs (n=5) were subjected closed-chest experimental MI. MR-MSCs (2.8 16x107 cells) injected intramyocardially under x-ray fluoroscopy. MRIs obtained on 1.5T MR scanner demonstrate location and correlated with histology. Contrast-enhanced MRI demonstrated successful injection infarct serial MSC tracking was two...
Abstract A method is proposed to estimate signal‐to‐noise ratio (SNR) values in phased array magnitude images, based on a region‐of‐interest (ROI) analysis. It shown that the SNR can be found by correcting measured signal intensity for noise bias effects and evaluating variance as mean square value of all pixel intensities chosen background ROI, divided twice number receivers used. Estimated are vary spatially within bound 20% with respect true result correlations between receivers.
Background Myocardial reperfusion is pivotal to the prognosis of patients with acute myocardial infarction. In these patients, coronary flow generally assessed by angiography and tissue perfusion tracer scintigraphy. This study was designed examine whether magnetic resonance imaging (MRI) provides information on damage beyond that supplied thallium scintigraphy after Methods Results Twenty-two recent infarction had ECG, echocardiography, angiography, fast contrast-enhanced MRI. Twelve also...
This paper reports a novel remotely actuated manipulator for access to prostate tissue under magnetic resonance imaging guidance (APT-MRI) device, designed use in standard high-field MRI scanner. The device provides three-dimensional guided needle placement with millimeter accuracy physician control. Procedures enabled by this include biopsy, fiducial marker placements, and therapy delivery. Its compact size allows both cylindrical open configuration scanners. Preliminary vivo canine...
Abstract This article presents a new method for measuring longitudinal strain in short‐axis section of the heart using harmonic phase magnetic resonance imaging (HARP‐MRI). The is tagged 1‐1 SPAMM at end‐diastole with tag surfaces parallel to plane. Two or more images are acquired such that have different encodings direction orthogonal image A dense map can be computed from these simple, fast computation. Simulations conducted study effect noise and choice out‐of‐plane encoding values....
Abstract Recently, intravascular catheter probes have been developed to increase signal‐to‐noise ratio (SNR) for MR imaging of blood vessels. Miniaturization these without degrading their performances is very critical in small vessels such as coronary arteries. Catheter coils a loop incorporated structure and limitations physical dimensions electromagnetic properties. The use loopless antenna proposed overcome problems. essentially dipole, which makes thin diameter possible, its electronic...
Abstract With the rapid growth of interventional MRI, radiofrequency (RF) heating at tips guidewires, catheters, and other wire‐shaped devices has become an important safety issue. Previous studies have identified some variables that affect relative magnitude this but none could predict absolute amount to formulate margins. This study presents first theoretical model wire tip can accurately its value, assuming a straight wire, homogeneous RF coil, does not extend out tissue. The local...
A method to calculate the ultimate intrinsic signal-to-noise ratio (SNR) in a magnetic resonance experiment for point inside an arbitrarily shaped object is presented. The SNR determined by body noise. solution obtained optimizing electromagnetic field minimize total power deposition while maintaining constant right-hand circularly polarized component of at interest. numerical approximation optimal found assuming superposition large number plane waves. This simulation allowed estimation...
Abstract A method is presented for measuring myocardial deformation in a breath‐hold with tagged cine MRI. Tagged images of human hearts are obtained arbitrary oblique planes on standard imager as few four heartbeats. The scan time has been reduced 16‐ to 64‐fold from previous techniques.© 1992 Academic Press,Inc.
Purpose The purpose of this study is to safely acquire the first human head images at 10.5T. Methods To ensure safety subjects, we validated electromagnetic simulation model our coil. We obtained quantitative agreement between simulated and experimental specific absorption rate (SAR). Using coil model, calculated radiofrequency power levels image subjects. conducted all experiments imaging sessions in a controlled lab whole‐body 10.5T scanner Center for Magnetic Resonance Research. Results...
Abstract Background Radiofrequency (RF) transmit arrays play a crucial role in various MRI applications, offering enhanced field control and improved imaging capabilities. Designing optimizing these arrays, particularly high‐field settings, poses challenges related to coupling, resonance, construction imperfections. Numerical electromagnetic simulation methods effectively aid the initial design, but discrepancies between simulated fabricated often necessitate fine‐tuning. Fine‐tuning...
Abstract Potentially important diagnostic information about atherosclerosis can be obtained by using magnetic resonance imaging and spectroscopy techniques. Because critical vessels such as the aorta, coronary arteries, renal arteries are not near surface of body, coils adequate to increase data quality desired levels. A few catheter MR receiver coil designs have been proposed for walls large blood aorta. These limited longitudinal coverage they too thick placed into small vessels. flexible,...
Abstract A technique for transperineal high‐dose‐rate (HDR) prostate brachytherapy and needle biopsy in a standard 1.5 T MRI scanner is demonstrated. In each of eight procedures (in four patients with intermediate to high risk localized cancer), MRI‐guided biopsies were obtained followed by placement 14–15 hollow catheters HDR brachytherapy. Mean needle‐placement accuracy was 2.1 mm, 95% errors less than 4.0 the maximum error 4.4 mm. addition guiding needles catheters, MR images also used...
In this work, we demonstrate the possibility to modify electric-field distribution of a radio frequency (RF) coil generate electric field-free zones in body without significantly altering transmit sensitivity. Because implant heating is directly related distribution, implant-friendly RF coils can be obtained by approach. We propose linear birdcage with zero plane as an example such coils. When coincides position, reduced, demonstrated phantom experiments. By feeding pulses identical phases...
The biological basis for the development of cerebro-cerebellar structures required posture and gait in humans is poorly understood. We investigated a large consanguineous family from Turkey exhibiting an extremely rare phenotype associated with quadrupedal locomotion, mental retardation, hypoplasia, linked to 7.1-Mb region homozygosity on chromosome 17p13.1–13.3. Diffusion weighted imaging fiber tractography patients' brains revealed morphological abnormalities cerebellum corpus callosum,...
In many studies concerning wire heating during MR imaging, a "resonant length" that maximizes RF is determined. This may lead to the nonintuitive conclusion adding more wire, so as avoid this resonant length, will actually improve safety. Through theoretical analysis using method of moments, we show behavior depends on phase distribution transmit field. If field has linear phase, with slope equal real part wavenumber in tissue, long wires always heat than short wires. order characterize...
We investigated the accuracy and feasibility of a system that provides transrectal needle access to prostate concurrent with 1.5 Tesla MRI which previously has not been possible.In 5 patients diagnosed cancer, guided intraprostatic placement gold fiducial markers (4 procedures) and/or biopsy (3 was performed using local anesthesia.Mean procedure duration 76 minutes all tolerated intervention well. Procedure related adverse events included self-limited hematuria hematochezia following 3 8...
Heat therapies such as hyperthermia and thermoablation are very promising approaches in the treatment of cancer. Compared with available modalities, magnetic fluid (MFH) yields better results uniform heating deeply situated tumors. In this approach, consisting superparamagnetic particles (magnetic fluid) is delivered to tumor. An alternating (ac) field then used heat corresponding tumor, thereby ablating it. However, one most serious shortcomings technique unwanted healthy tissues. This from...
Patients with active implants such as deep brain stimulation (DBS) devices are often denied access to MRI due safety concerns associated the radiofrequency (RF) heating of their electrodes. The majority studies on RF conductive have been performed in horizontal close-bore scanners. Vertical scanners which a 90° rotated transmit coil generate fundamentally different electric and magnetic field distributions, yet very little is known about this class We numerical simulations well phantom...
Abstract We have developed a method that can measure high‐energy phosphate metabolite concentrations in humans with 1D resolved surface‐coil NMR spectroscopy. The metabolites are measured by phosphorus ( 31 P) spectroscopy, and the tissue water proton 1 H) resonance from same volume serves as an internal concentration reference. requires only additional acquisition of H data set, simple calibration, performed separately, to determine ratio signal per nucleus. quantification is particularly...
Abstract Magnetic resonance imaging (MRI) may be an excellent tool to define atherosclerotic plaque composition, but surface MRI (SMRI) suffers from a low signal-to-noise ratio and resolution of arterial images. Intravascular (IVMRI) represents potential solution for acquiring high-quality in vivo images plaques. Isolated segments 11 thoracic human aortas obtained at autopsy were imaged by IVMRI using intravascular receiver catheter coil designed built our institution. Images compared with...