Purpose This study develops a method to obtain optimal estimates of absolute magnetization phase from multiple‐coil MRI data. Theory and Methods The element‐specific phases multi‐element receiver coil array are accounted for by using the real or virtual reference that is sensitive over entire imaged volume. virtual‐reference generated as weighted combination measurements all coils. phase‐corrected multiple complex images combined inverse covariance matrix. These methods tested on an agar...

Background: Three-dimentional (3D) vessel wall magnetic resonance imaging (MRI) sequences have emerged as new tools for evaluating carotid atherosclerosis. However, their reproducibility across different vendors has not yet been investigated, which only restricts use in multicenter studies but also hinders broader application clinical practice. In this study, we aim to assess the qualitative and quantitative on same subjects using matched 3D MRI both Siemens Philips scanners, specifically,...

Purpose The objective of this study was to determine whether a sodium phased array would improve breast MRI at 3 T. secondary create acceptable proton images with the in place. Methods A novel composite for combined proton/sodium T is compared coil single and channel. consists 7‐channel receive array, larger transmit coil, 4‐channel transceive array. new design utilizes smaller loops than typically used imaging, uses decoupling methods between loops, multichannel coil. reduces coupling...

This paper presents and evaluates a breast-specific magnetic resonance guided focused ultrasound (MRgFUS) system. A first-in-human evaluation demonstrates the novel hardware, sophisticated tumor targeting algorithm volumetric imaging (MRI) protocol.

Abstract In this study, a radio frequency phased array coil was built to image the breast in conjunction with magnetic resonance guided high‐intensity focused ultrasound (MRgHIFU) device designed specifically treat treatment cylinder reduced water volume. The MRgHIFU comprised of 10‐channel placed around an where nearest‐neighbor decoupling achieved capacitive shared leg. addition single loop at chest wall making total 11 channels. design presented work chosen based on ease implementation,...

Combining the unmatched soft-tissue imaging capabilities of magnetic resonance (MRI) with high precision robotics has potential to improve accuracy, precision, and safety a wide range image-guided medical procedures. However, goal highly functional MRI-compatible robotic systems not yet been realized because conventional electromagnetic servomotors used by robots can become dangerous projectiles near strong field an MRI scanner. Here we report novel servomotor design that is constructed from...

Abstract Purpose: To determine the apparent diffusion coefficient (ADC) values of lipid and hemorrhage in atherosclerotic plaque human carotid arteries vivo compare obtained from ex endarterectomy specimens. Materials Methods: In diffusion‐weighted imaging (DWI) plaques was performed using a 2D single shot Interleaved Multislice Inner Volume Diffusion Weighted Echo Planar Imaging (2D ss‐IMIV DWEPI) on 8 subjects who subsequently underwent endarterectomy. A total 32 slices used to construct...

Abstract A 3D projection reconstruction (3DPR) method was used to obtain in vivo 11 B images a large canine brain tumor model and human infused with borocaptate sodium (BSH). Studies were performed dogs without gliosarcomas implanted grown size of 2–3 cm. The 3DPR demonstrates signal‐to‐noise ratio (SNR) that allows qualitative kinetic studies the boron compound normal tissue head. measurements indicate initial uptake BSH be less than muscle no tissue. Moreover, found lag concentration blood...

Abstract This article presents a novel design for magnetic resonance imaging (MRI) gradient systems. may allow the development of MRI scanners that are capable large regions with high performance while minimizing potential nerve stimulation. The general concept system is spatial oscillation incorporated such each coil creates multiple, approximately linear oscillate in polarity. Separate radiofrequency (RF) arrays designed to be sensitive signals within region and thus signal measurements...

Purpose To demonstrate the interchangeable neck shape–specific (NSS) coil concept that supplements standard commercial spine and head/neck coils to provide simultaneous high‐resolution (hi‐res) imaging with high signal‐to‐noise ratio (SNR). Methods Two NSS were constructed on formers designed fit two different shapes. A 7‐channel (7ch) ladder array was a medium former, 9‐channel (9ch) large former. Both same preamp housing. Results The 7ch 9ch SNR gains of approximately 4 times 3 over...

The tradeoff between gradient performance factors, size of the imaging region, and physiological factors such as nerve stimulation typically leads to compromises in design ultimately suboptimal performance. Local systems can add some flexibility, but are cumbersome set up remove. In nearly all conventional MRI systems, use local gradients precludes more homogeneous whole body gradients. This paper presents concept dynamically selectable composite where be selected independently...

The purpose of this work was to design and construct a multichannel receive-only radiofrequency coil for 3T magnetic resonance imaging the human carotid artery bifurcation with optimized signal-to-noise ratio (SNR) in vessels along full extent neck. A neck phantom designed match anatomy subject representing body habitus often seen subjects arterial disease constructed. Sixteen circular elements were arranged on semirigid fiberglass former that closely fit shape phantom, resulting 16-channel...

The visualization of lesion formation in real time is one potential benefit carrying out radiofrequency ablation under magnetic resonance (MR) guidance the treatment atrial fibrillation. MR thermometry has to detect such lesions. However, performing during cardiac requires high temporal and spatial resolution a signal‐to‐noise ratio. In this study, local coil (2‐cm diameter) was developed investigate feasibility limited field view with accuracy speed. allowed high‐resolution (1 × 1 3 mm )...

The purpose of this work was to compare intracranial magnetic resonance angiography (MRA) image quality using three different radiofrequency coils. coil types included a reduced volume quadrature birdcage with endcap, commercially available head coil, and four-element phased-array coil. Signal-to-noise ratio (SNR) measurements were obtained from comparison studies performed on uniform cylindrical phantom. MRA comparisons data acquired 15 volunteers applying thick-slab three-dimensional...

Purpose To develop a method for rapid prediction of the geometric focus location in MR coordinates focused ultrasound (US) transducer with arbitrary position and orientation without sonicating. Methods Three small tracker coil circuits were designed, constructed, attached to housing breast-specific MR-guided US (MRgFUS) system 5 degrees freedom, connected receiver channel inputs an MRI scanner. A one-dimensional sequence applied three orthogonal directions determined each tracker, which was...

Purpose To evaluate the feasibility of diffusion tensor imaging (DTI) for medial and lateral rectus extraocular muscle (EOM) evaluation, to investigate normal DTI parameters EOM, compare with other skeletal muscle. Materials Methods Seven multiple sclerosis patients five subjects (M:F = 5:7, mean age 31.6 ± 9.2) without EOM disorder were included. The orbital DTIs using 2D‐ss‐IMVI‐DWEPI scanned b 500 s/mm 2 12 directions. diffusivity (MD) fractional anisotrophy (FA) EOMs in both orbits,...

Initial catheter-based renal sympathetic denervation (RSD) studies demonstrated promising results in showing a significant reduction of blood pressure, while recent data were less successful. As an alternative approach, the objective this study was to evaluate feasibility using magnetic resonance-guided high-intensity focused ultrasound (MRgHIFU) perform RSD porcine model. An intravascular fiber optic temperature probe used confirm energy delivery during MRgHIFU. This technique evaluated...

Purpose To evaluate the effect of a focused ultrasound transducer position and ground plane configuration on magnetic resonance image quality. Methods The with respect to MRI B0 field radiofrequency receive coils was evaluated in breast‐specific MRgFUS system an integrated RF phased‐array coil. Image signal‐to‐noise ratio at different locations. using replica 12 configurations. All evaluations were performed 3 Tesla. Results Both found have considerable overall SNR. A 67% increase SNR...