Novel MRI coil technology for safe imaging of children with implants

Abstract Magnetic resonance imaging (MRI) has revolutionized our approach to understanding human biology and pathology. Despite continuous advances, however, MRI remains largely inaccessible to a sizeable and growing group of patients who have conductive implants. The problem is exacerbated in children, for whom MR-

conditional devices are not readily available, leaving this vulnerable population unable to receive the standard of care that they need the most, and excluding them from scientific inquiries when they are most advantageous. The major risk of MRI in patients with conductive implants is the RF heating of the tissue due to the antenna

effect. This happens when the electric field of MRI scanner couples with the implanted device and amplifies the specific absorption rate (SAR) of the radiofrequency energy in the tissue surrounding the implant. MR-conditional implants have been approved by the FDA for adults, allowing patients to receive MRI under restricted conditions

that assure safety. Regrettably, however, neither MRI vendors nor device manufacturers have established safe MRI methodologies for children with conductive implants. We propose to develop, validate, and deploy a novel multi-platform MRI coil technology that allows ultra-fast and high-resolution MRI to be safely performed in children with conductive implants regardless of the implant location

in their bodies. Our solution is based on the idea that through innovative engineering we can control local electric fields generated by MRI on a case-by-case basis, thus avoiding interactions with the individual's implanted device wherever it happens to be in the body. Our preliminary results show that this technique can achieve a 20-

fold reduction in RF heating of cardiac implantable electronic devices (CEIDs), as well as implants of central nervous system (CNS) such as EcoG electrodes and Vagus Nerve Stimulation (VNS) devices. Such reduction in RF heating is sufficient to support all clinical and research sequences of interest in brain and body imaging.

Here we propose to take this proof-of-concept to the next level and develop, implement, validate, and deploy the first reconfigurable patient-adjustable (RPA) MRI coil technology tailored for imaging infants and young children. Specifically, we propose to 1) Develop and validate a patient-adjustable rotating MRI transmit coil that eliminates

RF heating in children with cardiac and CNS implants, and 2) Develop age-optimized close-fitting head and body receive arrays that integrate with the rotating coil and determine the range of imaging parameters that allow safe deployment of the ensemble coil system in children with implants. We are a multidisciplinary team including experts in MRI biophysics, instrumentation, and safety assessment,

clinicians with expertise and resources in pediatric radiology and pediatric surgery, as well as MRI vendors and industry partners. If successful, our work brings state-of-the-art MRI accessible to children with implants. This will allow methodical analysis of device parameters in emerging applications, improve our understanding of

existing indications, and brings unrestricted standard-of-care to pediatric patients with devices.