Magnetic Resonance Imaging Technology Development

National Institute Of Neurological Disorders And Stroke

Investigators

Linked publications, trials & patents

Abstract

The overall goal of this project is to develop high field MRI technology to improve the study of human brain anatomy and function. This includes the development of MRI scanner hardware such as radio frequency (RF) transmitters and detectors, peripheral equipment, MRI signal acquisition pulse sequences and image reconstruction and analysis software. The Advanced MRI section at NINDS (AMRI) has been at the forefront of this development and has been applying newly developed methods to both control subjects as well as patients with neurological disorders. As part of its efforts to improve MRI methodology, the AMRI section at NINDS carries the main responsibility for the development of NIH’s 11.7T human MRI scanner, a uniquely powerful system that will allow in-vivo neuroimaging with unprecedented clarity. Since the (second) installation of the magnet for the scanner in 2019, the manufacturer has continually had difficulty with its energization. In Fiscal Year (FY) 2025, excessive magnetic field drift was observed on the way to full field strength, indicating that use of this magnet for MRI at 11.7T would not be practical. We are currently waiting for options from the manufacturer for resolution of this problem, which if not satisfactory to NIH, may end this exciting project. In the light of these uncertain further delays, we have followed a conservative approach with the development of RF technology for this system. In addition, we have established collaborations with the 11.7 T sites in France and Korea to allow testing of our technology on their magnets. Among other things, this will for example enable us to test if NIH RF transmitters and detectors for 11.7T MRI have advantages in compared to what these sites are using. During FY 2025, AMRI collaborated with the engineering team of the laboratory of functional and molecular imaging (LFMI) to evaluate safety of its birdcage-type design transmitter. This device is slated to be used for the first human experiments, for which we plan to obtain investigation device exemption from the FDA. Lacking a working 11.7T system, our approach was to perform MRI thermometry at 3T, while irradiating using an external 500 MHz RF amplifier. Alternating irradiation with thermometry, we were able to measure the coil’s heating profile, which accurately corresponded to simulations as well as thermal probe measurement. A report describing this project was published in IEEE Transactions on Medical Imaging (2025). In a second project, we further developed and evaluated our approach to perform high resolution MRI based sensitized to magnetic susceptibility contrast and robust in the presence of motion. This type of contrast is particularly strong at high field and AMRI has a long-standing record in optimizing this contrast at 7T, identifying its biophysical underpinnings, and evaluating early application if neurodegenerative diseases to detect subtle changes in tissue iron accumulation and myelin loss. In anticipation of use at 11.7T, we collaborated with Jiaen Liu (UT Southwestern) and Xiaoping Wu (University of Minnesota) to optimize our 3D SW MRI method for anatomical MRI on the 10.5T human MRI at the Center of Magnetic Resonance Research in Minneapolis. Using their 16 channel RF transmit and 80 channel RF receive coil, robust 0.4mm whole brain anatomical data were obtained in a scan time of 10 minutes. A report describing the results of this work is in revision for Magnetic Resonance in Medicine (2025). In a third project, we further developed our novel approach to accelerate spin echo-based MRI experiments. Previously, we had demonstrated close to 2-fold increases in scan speed for applications like diffusion-weighted MRI, and measurement of brain fluid flow and tissue motion. Since applying for a patent in 2024, we have further improved this method by combining it with the another (established) approach based on simultaneous multi-slice MRI. This resulted in an additional 2-fold increase in scan speed for an overall 4-fold improvement. The new method was demonstrated for diffusion-weighted MRI, and reported in Magnetic Resonance in Medicine (2025). We are further evaluating this and similar approaches for the study of cerebro-spinal fluid movement with the cardiac cycle.