Eric William Fiveland

128-channel body MRI with a flexible high-density receiver-coil array.

To determine whether the promise of high‐density many‐coil MRI receiver arrays for enabling highly accelerated parallel imaging can be realized in practice.

Peripheral nerve stimulation characteristics of an asymmetric head-only gradient coil compatible with a high-channel-count receiver array

To characterize peripheral nerve stimulation (PNS) of an asymmetric head‐only gradient coil that is compatible with a commercial high–channel‐count receive‐only array.

Exploration of MR-guided head and neck hyperthermia by phantom testing of a modified prototype applicator for use with proton resonance frequency shift thermometry

Abstract Magnetic resonance thermometry (MRT) offers non-invasive temperature imaging and can greatly contribute to the effectiveness of head and neck hyperthermia. We therefore wish to redesign the HYPERcollar head and neck hyperthermia applicator for simultaneous radio frequency (RF) heating and magnetic resonance thermometry. In this work we tested the feasibility of this goal through an exploratory experiment, in which we used a minimally modified applicator prototype to heat a neck model phantom and used an MR scanner to measure its temperature distribution. We identified several distorting factors of our current applicator design and experimental methods to be addressed during development of a fully MR compatible applicator. To allow MR imaging of the electromagnetically shielded inside of the applicator, only the lower half of the HYPERcollar prototype was used. Two of its antennas radiated a microwave signal (150 W, 434 MHz) for 11 min into the phantom, creating a high gradient temperature profile (ΔTmax = 5.35 °C). Thermal distributions were measured sequentially, using drift corrected proton resonance frequency shift-based MRT. Measurement accuracy was assessed using optical probe thermometry and found to be about 0.4 °C (0.1–0.7 °C). Thermal distribution size and shape were verified by thermal simulations and found to have a good correlation (r2 = 0.76).

Validation of MR thermometry: Method for temperature probe sensor registration accuracy in head and neck phantoms

Abstract Purpose: Magnetic resonance thermometry (MRT) is an attractive means to non-invasively monitor in vivo temperature during head and neck hyperthermia treatments because it can provide multi-dimensional temperature information with high spatial resolution over large regions of interest. However, validation of MRT measurements in a head and neck clinical set-up is crucial to ensure the temperature maps are accurate. Here we demonstrate a unique approach for temperature probe sensor localisation in head and neck hyperthermia test phantoms. Methods: We characterise the proton resonance frequency shift temperature coefficient and validate MRT measurements in an oil–gel phantom by applying a combination of MR imaging and 3D spline fitting for accurate probe localisation. We also investigate how uncertainties in both the probe localisation and the proton resonance frequency shift (PRFS) thermal coefficient affect the registration of fibre-optic reference temperature probe and MRT readings. Results: The method provides a two-fold advantage of sensor localisation and PRFS thermal coefficient calibration. We provide experimental data for two distinct head and neck phantoms showing the significance of this method as it mitigates temperature probe localisation errors and thereby increases accuracy of MRT validation results. Conclusions: The techniques presented here may be used to simplify calibration experiments that use an interstitial heating device, or any heating method that provides rapid and spatially localised heat distributions. Overall, the experimental verification of the data registration and PRFS thermal coefficient calibration technique provides a useful benchmarking method to maximise MRT accuracy in any similar context.

Lightweight, compact, and high-performance 3T MR system for imaging the brain and extremities: FOO et al.

To build and evaluate a small‐footprint, lightweight, high‐performance 3T MRI scanner for advanced brain imaging with image quality that is equal to or better than conventional whole‐body clinical 3T MRI scanners, while achieving substantial reductions in installation costs.

Flexible, 31-Channel breast coil for enhanced parallel imaging performance at 3T

To design, build, and characterize the performance of a novel 3T, 31‐channel breast coil.

EKG‐based detection of deep brain stimulation in fMRI studies

To assess the impact of synchronization errors between the assumed functional MRI paradigm timing and the deep brain stimulation (DBS) on/off cycling using a custom electrocardiogram‐based triggering system

Tissue-Susceptibility Matched Carbon Nanotube Electrodes for Magnetic Resonance Imaging

Test disk electrodes were fabricated from carbon nanotubes (CNT) using the Carbon Nanotube Templated Microfabrication (CNT-M) technique. The CNT-M process uses patterned growth of carbon nanotube forests from surfaces to form complex patterns, enabling electrode sizing and shaping. The additional carbon infiltration process stabilizes these structures for further processing and handling. At a macroscopic scale, the electrochemical, electrical and magnetic properties, and magnetic resonance imaging (MRI) characteristics of the disk electrodes were investigated; their microstructure was also assessed. CNT disk electrodes showed electrical resistivity around 1 Ω·cm, charge storage capacity between 3.4 and 38.4 mC/cm2, low electrochemical impedance and magnetic susceptibility of -5.9 to -8.1 ppm, closely matched to that of tissue (∼-9 ppm). Phantom MR imaging experiments showed almost no distortion caused by these electrodes compared with Cu and Pt-Ir reference electrodes, indicating the potential for significant improvement in accurate tip visualization.

A magnetic resonance compatible E4D ultrasound probe for motion management of radiation therapy

There is recent interest in the use of ultrasound (US) and magnetic resonance (MR) imaging modalities for motion management during radiation therapy treatments. These imaging modalities aim to improve clinical outcomes by tracking tumor motion in order to increase the therapeutic ratio. The objective of this research is to develop an MR-compatible, real-time, three-dimensional ultrasound probe (E4D) for simultaneous MR and US imaging. The probe will be used in a system which leverages the real-time capabilities of ultrasound imaging and the soft-tissue image quality of MR for image guided radiation therapy (IgRT) of moving tumors.