BACKGROUND AND PURPOSE Previous studies have depicted arterial and aneurysmal anatomy with three-dimensional time-of-flight (3D-TOF) MR angiography before and after treatment with Guglielmi detachable coils (GDCs) and with CT angiography before and after treatment with stents and stent-grafts. We investigated the ability of time-resolved contrast-enhanced 3D MR angiography (3D MR digital subtra...

A new method for acquiring MR data in two dimensions is described. This is achieved by combining coils into an array so as to produce a unique local magnetic field within each coil when placed within the B(0) field of a standard MRI scanner. In this way each known location of a coil is associated with a unique resonant frequency. Each coil now represents a location of a pixel in the plane, and ...

RF behavior in the human head becomes complex at ultrahigh magnetic fields. A bright center and a weak periphery are observed in images obtained with volume coils, while surface coils provide strong signal in the periphery. Intensity patterns reported with volume coils are often loosely referred to as "dielectric resonances," while modeling studies ascribe them to superposition of traveling wav...

The idea of using parallel imaging to shorten the acquisition time by the simultaneous use of multiple receive coils can be adapted for the parallel transmission of a spatially-selective multidimensional RF pulse. As in data acquisition, a multidimensional RF pulse follows a certain k-space trajectory. Shortening this trajectory shortens the pulse duration. The use of multiple transmit coils, e...

B. Xu, B. K. Li, S. Crozier, F. Liu, Q. Wei School of Information Technology and Electrical Engineering, The University of Queensland, Brisbane, Queensland, Australia INTRODUCTION: High magnetic field (frequency) MRI technology has brought considerable engineering challenges in the form of ancillary hardware, including RF resonators. Studies in high frequency MRI have shown significant interact...

[Introduction] MR imaging of spinal cord is an important component of diagnostic work-up in some diseases such as multiple sclerosis (MS). In MS, the spinal cord is frequently involved and often in combination with lesions in the brain. In some MS cases, lesions have been found to involve only the spinal cord, particularly in the cervical spinal cord. Compared to brain imaging, spinal imaging i...

BACKGROUND AND PURPOSE Noninvasive evaluation of retinoblastoma treatment response has become more important due to increased use of eye-sparing treatments. We evaluated the relation between DCE-MR imaging and histopathologic parameters to determine the value of DCE-MR imaging in assessing tumor angiogenesis and prognostic features. MATERIALS AND METHODS Fifteen consecutive patients with reti...

Parallel Magnetic Resonance Imaging (pMRI) is a fast developing technique to reduce MR scanning time. In pMRI, multi-channel coils simultaneously receive a fraction of k-space data and the field of view (FOV) is then reconstructed with the coil profiles. The techniques for pMRI can be mainly divided in two groups: image domain techniques such as PILS, SENSE and Fourier domain techniques like SM...

Parallel transmission has gained considerable interest during the last few years [1,2]. The use of multiple individual RF transmit coils have been introduced to overcome B1 homogeneity limitations and to improve multi-dimensional RF pulses by shortening their duration. Of special concern in all these transmit applications is the specific absorption rate (SAR), which has to be kept below certain...

Low-field magnetic resonance imaging (MRI) has become increasingly popular due to cost reduction, artifact minimization, use for interventional radiology, and a better safety profile. The different applications of low-field systems are particularly wide (muscle–skeletal, cardiac, neuro, small animals, food science, as hybrid scanner hyperthermia, in radiology radiotherapy). scanners produce low...