A microscopic sensor developed by biomedical engineers from the Institute for Biomedical Engineering (ETH) in Zurich, Switzerland, has the ability to detect tiny changes in magnetic fields.

When it comes to MRI, the magnetic field is aggressively strong, which makes it hard for sensors to pick up small details. The new research, led by Klaas Prüssmann, a professor of bioimaging at ETH Zurich, has led to a way to integrate a digital radio receiver that decreases background noise to a low level during measurements.

“In addition to boosting absolute sensitivity at high field, the reported approach also affords superior relative sensitivity,” wrote Prüssmann et al. “At the level of one part per trillion, it is competitive with the most sensitive low-field magnetometry techniques devised to-date.”

Researchers used a patient’s chest and positioned the sensor in front of it, while the participant was inside an MRI scanner. Data showed tiny, regular changes in the magnetic field, revealing it was the patient’s heartbeat. The measurement curve is much like an electrocardiogram (ECG), except that it measures the contraction of the heart rather than electrical conduction.

This measurement technique also develops better contrast agents, paving the way for future developments in nuclear magnetic resonance spectroscopy for applications in biological and chemical research.