MRDust: Wireless Implant Data Uplink & Localization via Magnetic Resonance Image Modulation

Area of Science:

• Biomedical Engineering
• Medical Imaging
• Sensor Technology

Background:

• Magnetic Resonance Imaging (MRI) offers rich contrast but is limited by Nuclear Magnetic Resonance (NMR) physics, impacting sensitivity and resolution.
• Miniaturized implantable sensors provide localized physiological data but face communication and localization challenges, especially with multiple implants.

Purpose of the Study:

• To introduce MRDust, an active "contrast agent" that integrates active sensor implants with MRI.
• To enable direct encoding of highly localized physiological data into MR images, augmenting anatomical information.
• To demonstrate simultaneous data communication, localization, and image registration with multiple implants.

Main Methods:

• MRDust utilizes a micrometer-scale on-chip coil to actively modulate the local magnetic field.
• This modulation enables MR signal amplitude and phase modulation for digital data transmission.
• A 900 × 990 µm² chip with a 630 µm diameter on-chip coil was designed and tested in a 3T MRI scanner using a Spin-Echo Echo-Planar-Imaging (SE-EPI) sequence.

Main Results:

• Successful voxel amplitude modulation was demonstrated, encoding digital data into MR images.
• Achieved a contrast-to-noise ratio (CNR) of 25.58.
• The device exhibited a low power consumption of 130 µW.

Conclusions:

• MRDust successfully integrates active sensor implants with MRI, enabling direct encoding of localized physiological data.
• The technology holds potential for simultaneous data communication, localization, and image registration with multiple implants.
• This approach overcomes limitations of traditional MRI and implantable sensors, paving the way for advanced medical diagnostics.