MAG4Health 4He OPM-MEG System

The MAG⁴Health is a brand new fully integrated Optically pumped magnetometers (OPM)-MEG system based on proprietary quantum technology to enable a new generation of neuroimaging and MEG with a 48-sensor whole-head coverage system.

What is MEG?

Magnetoencephalography (MEG) is a noninvasive technology for imaging brain function in real-time. The approach is based on the measurement of magnetic fields generated (mainly) by synchronous dendritic current flow through neuronal assemblies outside the head. Mathematical modelling of these fields permits the development of three-dimensional images (termed source localisation) depicting the moment-to-moment variations in electrical activity as the brain responds to different experimental circumstances or cognitive demands.

What is OPM-MEG?

In recent years, a novel magnetic field sensing method has emerged in the MEG field. OPMs are magnetic-field sensors with equivalent sensitivity as SQUIDs that do not require cryogenic cooling. This has resulted in the development of novel MEG systems, and 'OPM-MEG' scanners are beginning to outperform the existing state of the art in terms of data quality, uniformity of coverage, motion robustness, and system complexity, while being a relatively new technology.

Many of these obstacles are starting to be removed by the next MEG technology generation. "OPM-MEG" has the potential to drastically surpass the existing state of the art by utilising quantum sensors that are known as optically pumped magnetometers (OPMs). This could result in improved data quality (higher sensitivity and spatial resolution), adaptation to any head size or shape (from babies to adults), motion resilience (participants can move freely during scanning), and a less sophisticated imaging platform (without reliance on cryogenics).

Optically Pumped Magnetometer (OPM) scanners have various advantages over traditional MEG scanners, including:

1. Increased signal sensitivity

2. Improved spatial resolution

3. Greater uniformity of coverage

4. Lifespan compliance

5. freedom of participant mobility during scanning

6. Lower operating costs and no need for supercooling

7. Reduce system complexity

What are the applications for OPM-MEG?

OPM-MEG can be used to measure a number of electrophysiological events that are often reported by MEG and EEG. Commonly, evoked responses to sensory stimuli of many modalities are evaluated, with OPMs giving high-fidelity measurements (Borna et al., Non-invasive functional-brain-imaging with an OPM-based magnetoencephalography system 2020).

Likewise, brain oscillations have been detected over many frequency bands with good SNR (Iivanainen et al., Potential of on‐scalp meg: Robust detection of Human Visual gamma‐band responses 2019). Using wearable OPM-MEG sensors, epileptiform activity has been characterised, suggesting the potential for future clinical application (Feys et al., On-scalp optically pumped magnetometers versus cryogenic magnetoencephalography for diagnostic evaluation of epilepsy in school-aged children 2022).

OPM-MEG has advantages over other functional neuroimaging techniques: fMRI, for instance, is limited to haemodynamic measurement, has poor temporal resolution, requires participants to be in a confined and loud area, and requires participants to remain still, making it difficult to quantify brain activity in naturalistic circumstances. While EEG and fNIRS provide realistic activity while scanning, they have either limited spatial (EEG) or temporal (fNIRS) resolution (fNIRS). For these reasons, within the landscape of functional imaging, OPM-MEG is beginning to stand out as an emergent tool that surpasses current technologies in a number of respects.

There are numerous sectors that stand to benefit from these advantages.

For instance:

• Greater spatial accuracy and sensitivity will be extremely beneficial for all functional mapping studies, including clinical applications (e.g., mapping epileptiform activity) and fundamental research. The scanning of neonates, infants, and children is easier with OPM-MEG than with SQUID MEG, which offers both clinical and fundamental research prospects (e.g., the study of neurodevelopmental problems) (e.g., examining how electrophysiological activity and connectivity change during the early years of life).
• The ability to scan while free movement makes MEG accessible to individuals who would find it difficult to endure a traditional scanner, such as those with mobility problems. Additionally, motion tolerance gives the opportunity for novel forms of exploration (e.g., immersive environments, or naturalistic scenarios).
• OPMs are not restricted to the study of the brain; they are also being used to evaluate the electrophysiology of the peripheral nervous system, muscles, heart, and even enteric nervous system.

References

Borna, A. et al. (2020) “Non-invasive functional-brain-imaging with an OPM-based magnetoencephalography system,” PLOS ONE, 15(1). Available at: https://doi.org/10.1371/journal.pone.0227684. 

Iivanainen, J., Zetter, R. and Parkkonen, L. (2019) “Potential of on‐scalp meg: Robust detection of Human Visual gamma‐band responses,” Human Brain Mapping, 41(1), pp. 150–161. Available at: https://doi.org/10.1002/hbm.24795. 

Feys, O. et al. (2022) “On-scalp optically pumped magnetometers versus cryogenic magnetoencephalography for diagnostic evaluation of epilepsy in school-aged children,” Radiology, 304(2), pp. 429–434. Available at: https://doi.org/10.1148/radiol.212453.