Publications by authors named "Fraser J L Robb"
Design of a volumetric cylindrical coil-tuned at 298 MHz for 7 T imaging.
Instrum Sci Technol
November 2023
The concept of a 2D cylindrical High Pass Ladder (2D c-HPL) is used in the development of this ultra high radio frequency (UHRF) volumetric head coil for 7T tuned at the Larmor frequency of 298 MHz. The architecture of the 2D c-HPL helps to overcome the challenges associated with non-uniform magnetic field distribution. The prototype consists of an individual resonating array of inductance-capacitance (LC) elements and each component is tuned to the precise frequency.
View Article and Find Full Text PDFLack of a body-sized, bore-mounted, radiofrequency (RF) body coil for ultrahigh field (UHF) magnetic resonance imaging (MRI) is one of the major drawbacks of UHF, hampering the clinical potential of the technology. Transmit field (B ) nonuniformity and low specific absorption rate (SAR) efficiencies in UHF MRI are two challenges to be overcome. To address these problems, and ultimately provide a pathway for the full clinical potential of the modality, we have designed and simulated two-dimensional cylindrical high-pass ladder (2D c-HPL) architectures for clinical bore-size dimensions, and demonstrated a simplified proof of concept with a head-sized prototype at 7 T.
View Article and Find Full Text PDFArticle Synopsis
- Magnetic resonance guided focused ultrasound (MRgFUS) is a non-invasive treatment method for neurodegenerative diseases that combines MRI imaging and ultrasound technology to target specific brain regions effectively.
- The development of a new 8-channel, flexible head coil called FUS-Flex enhances MRI signal quality by significantly increasing the signal-to-noise ratio (SNR) compared to standard body coils.
- Initial tests show that the FUS-Flex coil not only improves MRI image quality but also allows for more precise targeting and better monitoring of temperatures during MRgFUS procedures, potentially improving patient outcomes.
Article Synopsis
- HP C-MRI is a new imaging technique that helps differentiate aggressive prostate cancer from less serious types by analyzing lactate production after injecting hyperpolarised [1-C]pyruvate.
- The study found that HP C-MRI primarily measures metabolic activity in the cancer's epithelial cells rather than the surrounding stroma, correlating MRI results with the expression of key metabolic enzymes and transporters.
- This method was also validated through comparisons with existing data on tumours, showing consistent metabolic patterns that can help in identifying clinically significant disease based on cellular differences.
The purpose of this study is to investigate feasibility of estimating the specific absorption rate (SAR) in MRI in real time. To this goal, SAR maps are predicted from 3T- and 7T-simulated magnetic resonance (MR) images in 10 realistic human body models via a convolutional neural network. Two-dimensional (2-D) U-Net architectures with varying contraction layers and different convolutional filters were designed to estimate the SAR distribution in realistic body models.
View Article and Find Full Text PDFMagnetic resonance imaging systems rely on signal detection via radiofrequency coil arrays which, ideally, need to provide both bendability and form-fitting stretchability to conform to the imaging volume. However, most commercial coils are rigid and of fixed size with a substantial mean offset distance of the coil from the anatomy, which compromises the spatial resolution and diagnostic image quality as well as patient comfort. Here, we propose a soft and stretchable receive coil concept based on liquid metal and ultra-stretchable polymer that conforms closely to a desired anatomy.
View Article and Find Full Text PDFPurpose: To deploy clinically, a combined parallel imaging compressed sensing method with coil compression that achieves a rapid image reconstruction, and assess its clinical performance in contrast-enhanced abdominal pediatric MRI.
Materials And Methods: With Institutional Review Board approval and informed patient consent/assent, 29 consecutive pediatric patients were recruited. Dynamic contrast-enhanced MRI was acquired on a 3 Tesla scanner using a dedicated 32-channel pediatric coil and a three-dimensional SPGR sequence, with pseudo-random undersampling at a high acceleration (R = 7.