A scalable superconducting dual-shielded fetal magnetocardiography system

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PROJECT SUMMARY There are 26,000 unexplained fetal deaths in the US and over 4 million worldwide annually. Fetal cardiac arrythmia is a significant cause of fetal demise and is diagnosed in 1-3% pregnancies. While most occurrences are benign, serious arrhythmia can lead to life-threatening complications if undiagnosed or untreated. Echocardiography and cardiotocography have been widely used to assess fetal cardiac function; however, their use has not reduced the incidence of fetal sudden death. Fetal magnetocardiography (fMCG) records the magnetic fields generated by the electrical activity of the heart, enabling direct assessment of fetal heart electrophysiology. However, the only FDA-approved fMCG system uses expensive SQUID sensors and requires a dedicated magnetically shielded room (MSR) to achieve the necessary sensitivity to detect the fetal magnetic signal above environmental magnetic interference. Thus, the prohibitive expense and impracticality limits the use of a potentially life-saving device and there remains significant need for a sensitive device that is affordable and accessible to improve outcomes for fetal cardiac arrhythmias. Applied Physics Systems’ (APS) solution is an integrated fMCG system that uses the more affordable, optically pumped magnetometer sensors (OPMs), which are now as sensitive as SQUID sensors, with an innovative superconducting dual-shield. A laboratory prototype of an OPM-based fMCG with a person-sized ferromagnetic shield has already been developed and a human subject study demonstrated feasibility of an OPM-based fMCG system as sensitive and accurate as SQUID-based fMCG, but at a fraction of the cost. However, the shield in the laboratory prototype allowed higher noise in the fMCG recordings compared to SQUID in an MSR. This shielding is the remaining technical hurdle to reach commercialization. Superconducting shields have superior shielding compared to ferromagnetic shields and APS has 40 years of success in commercializing superconducting dual-shielding in rock magnetometer systems. Our preliminary data demonstrates proof of concept of improved OPM sensitivity within such a shielding system. Therefore, APS will build upon these studies to create a superconducting dual-shield system to reduce environmental noise, thus improving signal sensitivity and usability of the system through 3 aims. In Aim 1, we will scale up our superconducting dual-shield system to be person-sized and design the OPM sensor array and its associated software. We will demonstrate the shielding performance of our system matches or exceed that of a standard MSR and thermal performance of the superconducting system. In Aim 2, we will fully assemble the fMCG system with a patient conveyance system and confirm it meets electrical safety standards. In Aim 3, we will conduct human subject studies, first in non- pregnant subjects to confirm safety, then in pregnant subjects to confirm sensitivity and accuracy of our fMCG system compared to the FDA-approved SQUID-based fMCG system.