Researchers from University College London (UCL) have developed a method to map the electrical conductivity of the heart to identify anomalies where it is misfiring. This technique could be used to diagnose atrial fibrillation and to target potential surgeries to the heart.

The team imaged solutions with a conductivity comparable to that of live tissues down to a sensitivity of 0.9 Siemens per metre and to a resolution of one cm using an unshielded atomic magnetometer with an AC magnetic field. These solutions were 5 ml in volume each to match the expected need of applications in AF diagnoses. 

The signal was detected using Rubidium-based quantum sensors, which the team developed specifically to image small volumes accurately and consistently over a several days, with areas of brightness indicating high conductivity.

Being able to detect conductivity at less than one Siemens per metre is an improvement of 50 times on previous imaging results and demonstrates that the technique is sensitive and stable enough to be used to image biological tissues in an unshielded environment.

“Electromagnetic induction imaging has been successfully used in a range of practical uses such as non-destructive evaluation, material characterization, and security screening, but this is the first time that it’s been shown to be useful for biomedical imaging,” says UCL professor Ferruccio Renzoni, PhD. “We think it will be safe to use as it would expose organs, such as the heart, to one-billionth the magnetic field commonly used in MRI scanners.”

Read more from University College London and find the study in Applied Physics Letters.