A surface coil for MRI consisted of two concentric loops was developed to produce brain images with a commercial MR imager. Prior to build the coil prototype, the magnetic field (B1) generated by the coil was numerically simulated. This field simulation is based on the Biot-Savart law for the circularand square-shaped loop coils. From these theoretical results, we can appreciate an improvement ...

background: the most favorable feature of nickel-titanium (ni-ti) alloys in orthodontics is producing constant forces in a wide deformation range. ni-ti closed coils produce compressive strength and can be used for several purposes such as space closure. the aim of this study was to evaluate the effects of the aging process (temperature changes and prolonged strain) on ni-ti closed coils and to...

OBJECTIVES Intraoperative magnetic resonance imaging is a unique tool for visualizing structures during resection and/or for updating any kind of neuronavigation that might be hampered as a result of brain shift during surgery. Advanced MRI techniques such as perfusion-weighted imaging have already proven to be important in the initial diagnosis preoperatively, but can also help to differentiat...

Introduction Apart from being a non-invasive imaging modality, MR breast imaging can also provide high spatial and temporal resolution images of the breast, which is advantageous for fast and accurate diagnosis of disease. Studies have shown that it is possible to acquire high resolution breast images at ultra high fields with dedicated transceive RF breast coils that can transmit homogenous lo...

Protocol The article by Naggara et al on the added value of high-resolution MR imaging in the diagnosis of vertebral artery dissection shows an interesting comparison between routine clinical MR imaging examinations as performed in their institution and high-resolution imaging acquired with dedicated coils and different techniques. The study enhances the difficult diagnostic task of demonstrati...

PURPOSE To define the clinical and prognostic role of MR in a pediatric population with spinal cord injury. METHODS Fifteen children underwent MR 12 hours to 2 months postinjury using decoupled surface coils and ventilator support as needed. MR was correlated retrospectively with clinical, CT, and radiographic findings. RESULTS On MR, of seven children with spinal cord neurologic deficits, ...

S. Sathyanarayana, P. Aksit, A. Arepally, P. Karmarkar, M. Solaiyappan, E. Atalar Electrical and Computer Engineering, Johns Hopkins University, Baltimore, Maryland, United States, Global Applied Science Laboratory, GE Healthcare, Milwaukee, Wisconsin, United States, Radiology, Johns Hopkins Medical Institutes, Baltimore, Maryland, United States, Electrical and Computer Engineering, Bilkent Uni...

In this work experimental and numerical studies of the MR signal were performed at frequencies ranging from 64 MHz to 485 MHz, utilizing three different MRI coils: a single-strut transverse electromagnetic (TEM)-based coil, a TEM resonator, and a high-pass birdcage coil. The experimental analyses were conducted using 1.5 and 8 Tesla whole-body systems and volume RF head coils. The simulation da...

BACKGROUND AND PURPOSE To compare the utility of contrast-enhanced MR Angiography (CE-MRA) with digital subtraction angiography (DSA) after endovascular treatment of intracranial aneurysms with Guglielmi detachable coils. METHODS From April 1999 to August 2002, 106 patients with 107 aneurysms treated by endovascular coiling using Guglielmi detachable coils underwent simultaneous DSA and CE-MR...

Proton and heteronuclear MRI/MRS using dual-tuned (DT) coils could provide both anatomical and metabolic images without repositioning the subject. However, it is technologically challenging to attain sufficiently electromagnetic (EM) decoupling between the heteronuclear channel and proton channel, and keep the imaging areas and profiles of two nuclear channels highly matched. In this study, a h...