Modern MRI scanners have improved dramatically in image quality and speed over the past few decades. Innovations in hardware design and development in technological capability are the major driving forces for these advancements. Hardware breakthroughs include advanced RF, gradient and upgraded magnet technologies. Although most MRI scanners are marketed by vendors (e.g., Siemens, GE, Philips), the original ideas often come from academic research laboratories, including the original MRI scanner design in the 1970s, actively shielded gradient coils in the 1990s, RF phased array coils in the 1980s-90s and RF parallel transmission technology in the 2000s. Academic labs have played a significant role in the development of MRI function.
Additionally, it is agreed that hardware is the basis for novel technological capability. In the early 1990s, for example, the groups that first captured functional MRI (fMRI) signals in the human brain were those capable of building specialized gradient coils and thus implementing fast imaging techniques (EPI). New truths become evident when new tools become available (Rosalyn Yalow). As such, the first-round proposals awarded by the BRAIN Initiative largely involved hardware innovations (e.g., R24 on next-generation human brain imaging).
Aligned with the above belief, our mission is to improve the diagnosis and prevention of disease by solving critical challenges in imaging through the expansion of innovational ideas in both hardware and software design. Our current novel MR head coil system under development will provide a new data acquisition platform for fMRI, which has the potential to meet the challenge at high fields for comprehensive whole-brain imaging, including the prefrontal cortex (PFC) and temporal lobes (TLs).
We are the first to propose a novel MRI scanner platform technology known as integrated Parallel Reception, Excitation and Shimming (iPRES). This new concept combines B0 shimming and radio frequency (RF) into a single coil array. iPRES technology has the potential to be the revolutionary design for next-generation RF coils/phased arrays, one of three major hardware components of MRI scanner design. Since 2013, this new concept has been a hot topic in the world's largest MR community, the International Society for Magnetic Resonance in Medicine. The new concept has been highlighted in several plenary lectures, including those hosted by major vendors such as Siemens and GE Healthcare.
Current studies aim to fully develop the potential of this technology for improving the diagnosis and prevention of diseases by solving challenges in imaging — for example, the unmet challenge in high-fidelity whole brain functional MR imaging at ultra-high field, including the prefrontal cortex and temporal lobe. The platform technology also benefits diffusion tensor imaging (DTI), spectroscopic imaging (sMRI) and high-resolution structure imaging in these important brain regions.
The new iPRES technology combines radio frequency (RF) and direct current in one single coil array, rather than using separate arrays for parallel RF reception and B0 shimming. iPRES relies on a novel circuit design that allows a radio frequency current (for excitation/reception) and a direct current (for B0 shimming) to coexist independently in the same coil without undesired interference. The underlying principle — that currents or waves at different frequencies can coexist independently in the same conductor or media without undesired interference between them — is simple and widespread in electrophysics and communications applications.
Taking advantage of multichannel RF receivers (e.g., 32-channel) commonly available on modern scanners, the new concept integrates localized multicoil B0 shimming into a conventional RF phased array by innovated coil design. Therefore, conventional multiple-channel receive arrays can be replaced by the new integrated shim-RF array. Compared with a conventional RF coil, the integrated coil provides the add-on ability for multicoil local B0 shimming without compromising RF sensitivity. Relative to the standard B0 shimming coils on modern scanners, multicoil local shimming has proved to be a powerful strategy for achieving an unprecedented homogeneous field in the human and mouse brain. This integrated shim-RF array is a new hardware platform that can provide a variety of MRI practitioners with improved image spatial and temporal resolution in vivo for both anatomical and functional MR imaging, leading to better diagnostic information for a variety of clinical diseases.
The MRI hardware engineering program brings together a technical development team (physicists and engineers) and a clinical application team (radiologists, neurologists and psychologists). As a general imaging platform, we collaborate with a wide range of investigators from various hospitals, universities and industry.